F`]] @@@ @@@@33 @fsU]] EN DB ] #*   ~x Dando19746]Harris-Warrick1996^ Kopell1993fW Marder1999XNonnotte1990W Selverston1979C:\DOCUME~1\FARZAN\LOCALS~1\Temp\PubMed (NLM).tmp- Selverston1979. Selverston19809 Selverston1980 Selverston1981 Selverston1982 Selverston1982: Selverston1982; Selverston1983< Selverston1983= Selverston1983 Selverston1984S Selverston1984T Selverston1984M Selverston1984/ Selverston1984 Selverston1985> Selverston19850 Selverston1986? Selverston1986 Selverston19871 Selverston19872 Selverston1987 Selverston19883 Selverston19884 Selverston19885 Selverston19886 Selverston19888 Selverston1989 Selverston1989 Selverston1990 Selverston1990 Selverston1991 Selverston1991 Selverston1992 Selverston1992 Selverston1992 Selverston1993 Selverston1993 Selverston1994 Selverston19949W Selverston1995 Selverston19957 Selverston1995 Selverston1996X Selverston1997 Selverston1997A Selverston1997Y Selverston1998& Selverston1998 Selverston1999$ Selverston1999% Selverston1999 Selverston2000+ Selverston20000B Selverston2000 Selverston2001 Selverston20026 Selverston2003k Selverston2003D Sen1996 Sen1998E Sharman2000F Sharp1992p Sharp1993G Sharp1993H Sharp1993o Sharp1994 Sharp1995I Sharp1996MSi-Liang1977 Siegel19939 Siegel1994J Siegel1994KSigvardt1982LSigvardt1982{Sigvardt1997Sillison1986N Simmers1987R Simmers1988S Simmers1988P Simmers1990 Simmers1991h Simmers1993 Simmers1994 Simmers1994f Simmers1995O Simmers1995Q Simmers1995g Simmers1997Z Simmers1998[ Simmers1998^ Simmers1998 Simmers1998 Simmers1998y Simmers1998\ Simmers1999d Simmers1999e Simmers19999 Simmers2000 Simmers2000z Simmers2000] Simmers2001 Simmers2001) Simmers2002{ Simmers2002 Simon2001 Simon2003 Simon2005 Sirchia1987y Siwicki1986 Skarbinski19988[ Skiebe1994L Skiebe19959 Skiebe19977 Skiebe19999T Skiebe1999W Skiebe1999Z Skiebe2000U Skiebe2001Y Skiebe2002\ Skiebe2002V Skiebe2003X Skiebe2003] Skilleter1986_ Skinner1993^ Skinner1994I Skinner1996 Sosa20040 Soto19979* Soto-Trevino1998w Soto-Trevino1999` Soto-Trevino2001a Spirito1975bSpruston1991 Stein2000Q Stein2004- Stewart2003c Storch1989l Storm1995 Strassburg2004d Suh1988eSullivan1978g Suthers1981f Suthers19848Sweedler200207Sweedler20030h Swensen2000i Swensen2000 Swensen2001j Swensen2001 Szelier1999 Szucs2000B Szucs2000 Szucs2001k Szucs2003. Szuts1999Takemoto1986l Tanner1995 Taveras1983r Tazaki1986t Tazaki1986m Tazaki1988s Tazaki1990o Tazaki1991u Tazaki1991J Tazaki1992 Tazaki1992n Tazaki1993p Tazaki1993q Tazaki1994v Tazaki1997v Tazaki1997w Tazaki2000w Tazaki2000y Terio1993# Thirumalai19998 Thirumalai2002 Thirumalai2002x Thirumalai20027 Thirumalai2003 Thirumalai2003 Thirumalai2003y Thoby-Brisson1998z Thoby-Brisson2000{ Thoby-Brisson2002|Thompson1982` Thoroughman2001 Thuma2000} Thuma2002~ Thuma2003 Thuma2003 Tierney1992 Tierney1997 Tierney1999 Torres2001 Torres2001" Tresch20000# Truman1996! Truman19989" Truman20010 Tsien1996 Tsung1992 Turrigiano1989 Turrigiano1990 Turrigiano1990 Turrigiano1991 Turrigiano1992_ Turrigiano1993 Turrigiano1993 Turrigiano1994 Turrigiano1994K Turrigiano1995 Turrigiano1995q Turrigiano1996 Turrigiano1996 Turrigiano1999Van Weel1970 Van Wormhoudt1994 Varona2000B Varona20000 Varona2001 Varona2001 Vedel1974 Vedel1977 Vedel1977 Vedel1979 Vincent1996 Volkovskii2000;Wadepuhl19838<Wadepuhl19838=Wadepuhl19838Wadepuhl1987 Wagner1986K Wales1976 Wales1976 Walton19755 Warshaw1976 Weaver2002 Weaver2003 Weaver2003 Weaver2003) Webb20000X Weckwerth2003Weigeldt1993 Weimann1989 Weimann1990 Weimann1991 Weimann1992 Weimann1992 Weimann1992 Weimann1992 Weimann1993 Weimann1993 Weimann1994z Weimann1997 Weimann1997Wilensky2003Williams1907 Willms1997 Willms1997i Withers1998\Wollenschlager2002 Wood2000 Wood20010 Wood2002 Wood2004 Wootton1995_ Wu19909 Xu20040 Yang1986 Yaple2001IYarotsky2003 Yonge1924 Zarrin1994 Zhang1992 Zhang1994 Zhang1995 Zhang1995 Zhang1997J Zhang2003 Zhang2003 Zhang2003 Zhang2004 Zilberstein2002 Zilberstein2002) Zipfel2000 Zirpel1993Simmers1999e Simmers19999 Simmers2000 Simmers2000] Simmers2001 Simmers2001) Simmers2002 Simon2001 Simon2003 Sirchia1987y Siwicki1986 Skarbinski19988[ Skiebe1994L Skiebe19959 Skiebe19999T Skiebe1999W Skiebe1999Z Skiebe2000U Skiebe2001Y Skiebe2002\ Skiebe2002V Skiebe2003X Skiebe2003] Skilleter1986_ Skinner1993^ Skinner1994I Skinner1996* Soto-Trevino1998w Soto-Trevino1999` Soto-Trevino2001a Spirito1975bSpruston1991Q Stein2004- Stewart2003c Storch1989d Suh1988eSullivan1978f Suthers19848Sweedler200207Sweedler20030 Swensen2001 Szelier1999 Szucs2000B Szucs2000 Szucs2001. Szuts1999Takemoto1986 Taveras1983J Tazaki1992 Tazaki1992y Terio1993# Thirumalai19998 Thirumalai2002̈ Thirumalai20027 Thirumalai2003 Thirumalai2003 Thirumalai2003` Thoroughman2001 Thuma2000" Tresch20000# Truman1996! Truman19989" Truman20010 Tsien1996_ Turrigiano1993K Turrigiano1995q Turrigiano1996 Varona2000B Varona20000 Vedel1974 Vedel1977 Vedel1979 Vincent1996 Volkovskii2000;Wadepuhl19838<Wadepuhl19838=Wadepuhl19838Wadepuhl1987 Wagner1986K Wales1976 Walton19755 Weaver2002) Webb20000X Weckwerth2003Weigeldt1993̉ Weimann1992 Weimann1992 Weimann1992 Weimann1992 Weimann1993z Weimann1997 Willms1997̺ Willms1997i\Wollenschlager2002 Wood20010_ Wu19909 Yaple2001IYarotsky2003 Zarrin1994 Zhang1992 Zhang1997J Zhang2003 Zilberstein2002) Zipfel200002  T!"& )'.-1$%34(+5/82<0@9BC>FH=E?KMGNQRPJSXZ[\V]`abcO_ghijdmspqtuwz{}kr|xy AuthorspJournals tKeywords o                                D  Abarbanel, H.Abarbanel, H. D. Abbott, L. F. Abbott, L.F. Abel, B. Abele, L.G. Adams, S.R. Adelman, G. Agricola, H. Akoev, G. N. Albert, J. Allen, J.A. Alspector, J. Altman, J. An, W. F.Anderson, D.T.Anderson, W. W.Anderson, W.W. Ando, F. Arbib, M.A.Archavsky, Y.I. Armstrong, D.Arshavsky, Y. I. Ascher, P. Atwood, H. L. Atwood, H.L. Auerbach, A. Ayali, A. Ayers, J. Ayers, J. L. Ayers, J.L. Baar, E. Bal, T Bal, T. Baldwin, D.Baldwin, D. H. Baldwin, D.H. Balkema, A.A. Barazangi, N. Barker, D. L. Barker, D.L. Barker, P.L. Baro, D. J. Baro, D.J. Baro, D.L. Barth, G. Bartos, M. Bedrov, Y. A.Beenhakker, M. P.Belanger, J. H. Beltz, B. Beltz, B. S. Bem, T. Benson, J.A. Bianchi, A.L. Bidaut, M.Billimoria, C. P.Birmingham, J. T.Bittner, G. D. Blanck, J. Blitz, D. M. Bohm, H. Booth, J.D. Booth, V. Borner, J. Bose, A. Bucher, D. Buchholtz, F. Buchman, E. Buchner, K.Budelli, R. W. Buisson, A. Bullock, T.H. Bush, B.M.H.Cabirol-Pol, M. J. Cain, S. D. Caine, E.A. Calabrese, R.Calabrese, R. L.Caldwell, R.L.Callaway, J. C. Calvin, W. H. Calvin, W.H. Camhi, J. Cardi, P. Carew, T. Carew, T.C. Carlton, C.E.Casasnovas, B. Casey, M.Castelfranco, A. M. Cattaert, D.Cazalets, J. R.Cazaletz, J.R.Cervates-Peres, F. Chabaud, F. Chang, E. S. Chanussot, B. Cherny, E. Chiba, C. Christie, A.Christie, A. E.Claiborne, B. J.Claiborne, B.J. Clarac, F. Clark, M. C. Clason, T. A.Cleland, T. A. Cleland, T.A. Clemens, S. Cohen, A.H. Cohen, L. Cohen, N. Cole, C.L.Coleman, M. J. Combes, D.Coniglio, L. M.Coniglio, L.M. Cooke, I. M. Cooke, I.M. Coombs, E.G. Corey, S.Cottrell, G.W. Cournil, I. Cowan, J.D. Cowan, N. G.Creutzfeldt, O. Dall, W. Dando, M. R. Dando, M.R. Davis, K. R. de Vente, J. Degos, L. Deitmer, J.W.DeKlotz, T. R.Devanit-Saubie, M. Dever, J. J. Dever, T. E.DiCaprio, R. A. Dick, O. E.Dickinson, P. S.Dickinson, P.S. Dietel, C. Dindle, H. Dircksen, H. Doshi, M. Dreger, M. Duce, I.R. Durbin Dybek, E.Edwards, D. H., Jr.Edwards, J. M. Eeckman, F.H.Eeckmann, F.H. Eigg, M. H. Eisen, J. S. Eitner, E. El Manira, A. Elsner, N. Elson, R. Elson, R. C.Epstein, I. R. Epstein, I.R. Epstein, S. Erber, J Erber, J. Evans, B. Evers, J. F. Ewald, D.A. Ewer, J. Factor, J.R.Fairfield, W. P. Falcke, M. Farnham, J. Faumont, S. Felder, D.L.Felgenhauer, B.E. Fenelon, V.Fenelon, V. S.Fentress, J.C. Ferrell, W.R. Fickbohm, D. Flamm, R. Flamm, R. E. Flamm, R.E.Fleischer, A.G. Florkin, M. Fraser, M. French, L. French, L. B. Friedi, M. Friend, B. J. Friesen, J.A. Frost, W. N. Ganeshina, O. Garzino, V. Gassie, D. V.Gassie, D. V., Jr. Gassie, D.V. Geffard, M. Gibson, R. Gielen, S. Giles, C.L.Gisselmann, G. Glaser, D.A. Glasser, S. Glowik, R. M.Goaillard, J. M.Godleski, M. S. Gola, M. Goldberg, D.Goldman, M. S. Golomb, D. Golowasch, J.Golowasch, J.P.Gossard, J.-P. Govind, C. K. Govind, C.K. Goy, M. F. Graubard, K.  !""&& &'')').1.-.-111111$%%$$$$111%%333+(4++5555555/////82222<<<<<00@9@9@B@B@@@BBCC>C>FFH=====??E?H=====?===KKMMMMGMGMMKMMGGGNNNNGNNQQQQQQQPJJJQRRPPRJSSSSSXlLobsters/*physiology94202013D>Elson, R. C. Panchin, Y. V. Arshavsky, Y. I. Selverston, A. I.haMultiple effects of an identified proprioceptor upon gastric pattern generation in spiny lobstersPIAnimal Electrophysiology Ganglia, Invertebrate/physiology In Vitro Lobsters/*physiology Mastication/physiology Mechanoreceptors/*physiology Motor Neurons/physiology Peripheral Nerves/physiology Proprioception/*physiology Stomach/anatomy & histology/innervation/*physiology Support, U.S. Gov't, P.H.S. Tooth/innervation/physiologyr1. Using deafferented preparations of the stomatogastric nervous system of spiny lobsters (Panulirus interruptus), we stimulated the central soma of the Anterior Gastric Receptor neuron (AGR) and analyzed sensorimotor integration in the gastric central pattern generator during rhythm production. 2. Driving AGR to spike tonically at lower frequencies (10-20/s) accelerated the gastric rhythm, while higher frequencies (> or = 30/s) suppressed it. 3. Shorter spike trains in AGR evoked phase-dependent resetting of the gastric rhythm. Repetitive trains could entrain rhythms to both longer and shorter cycle periods. Some pattern-generating effects are consistent with effects upon the lateral gastric neuron, an influential member of the gastric mill network. 4. AGR affected the burst intensity of many of the gastric neurons in specific, complex ways. Some power-stroke motor neurons were excited because AGR activated excitatory, premotor interneurons (E cells). However, AGR also activated parallel, seemingly inhibitory inputs, whose mechanism remains unclear. Still other effects on motor neurons may be mediated partly by synaptic interactions within the network. J Comp Physiol [A] 1994 174i3a 317-29  0tActa Zootaxonomica Sin Adv PhysiolAJNR Am J Neuroradiol$Am Report R J Comm Inland Fish Am ZoolAmer ScientistAnn N Y Acad SciAnn Sci Nat ZoolAnnu Rev Neurosci Annu Rev Pharmacol ToxicolAnnu Rev PhysiolArch Int Physiol BiochimAust J Mar Freshw ResBehav Brain Sci Bioessays Biol Bull Biol CybernBiologie in inserer Zeit. Biophys JBr J PharmacolBrain Behav Evol Brain ResBrain Res BullBrit J Exp BiolC R Acad Sci ParisC R Acad Sci Paris D Can J Zool$Cell Mol Biol (Noisy-le-grand)Cell Tissue ResComp Biochem PhysiolComp Biochem Physiol C Curr BiolCurr Opin NeurobiolCurr Opin NeuronbiolDev Genes EvolEur J NeurosciForma et FunctioGene IEEE Trans Circuits SystemsIEEE Transactions, SMCInvert NeurosciJ Anat Physiol J Comp NeurolJ Comp PhysiolJ Comp Physiol A85J Comp Physiol A Neuroethol Sens Neural Behav PhysiolJ Comp Physiol [A]J Comput Neurosci J Crust Biol J Exp BiolJ Exp Mar Biol Ecol J Exp Zool J Gen PhysiolJ Histochem Cytochem J Morph J MorpholJ Neural Networks J Neurobiol J Neurochem J NeurocytolJ Neurophysiol J NeurosciJ Neurosci Methods J PhysiolJ Physiol (Lond)J Physiol (Paris)J Physiol Paris Life SciMar Behav Physiol Mar Biol Mem Fac Fish (Kagoshima Univ)Microsc Res Tech Mol Neurobiol Mol Pharmacol Nat Neurosci NatureNaturwissenschaften Network Neural Comp Neural Comput Neural NetwNeurocomputing Neuron Neurosci Lett Neuroscience Neurosignals New Scientist Peptides Pflugers ArchPhil Trans Roy Soc B("Philos Trans R Soc Lond B Biol Sci@ pyloric constrictor (PY) synapse and increasing PY input resistance. As previously reported, graded inhibition was enhanced at these two LP output synapses. We conclude that DA can differentially modulate the spike- evoked and graded components of synapses between members of a central pattern generator network. At the synapses we studied, actions on the presynaptic cell predominate in the modulation of graded transmission, whereas effects on postsynaptic cells predominate in the regulation of spike-evoked IPSPs.J Neurophysiol 1998794 2063-9&Ayali, A. Harris-Warrick, R. M.db\Monoamine control of the pacemaker kernel and cycle frequency in the lobster pyloric network@9Animal Biogenic Monoamines/*physiology Dopamine/pharmacology/physiology Efferent Pathways/physiology Female Ganglia, Invertebrate/*physiology Lobsters/*physiology Male Nerve Net/*physiology Neurons/drug effects/physiology Octopamine/physiology Pylorus/*innervation Serotonin/physiology Support, U.S. Gov't, P.H.S.The monoamines dopamine (DA), serotonin (5HT), and octopamine (Oct) can each sculpt a unique motor pattern from the pyloric network in the stomatogastric ganglion (STG) of the spiny lobster Panulirus interruptus. In this paper we investigate the contribution of individual network components in determining the specific amine-induced cycle frequency. We used photoinactivation of identified neurons and pharmacological blockade of synapses to isolate the anterior burster (AB) and pyloric dilator (PD) neurons. Bath application of DA, 5HT, or Oct enhanced cycle frequency in an isolated AB neuron, with DA generating the most rapid oscillations and Oct the slowest. When an AB- PD or AB-2xPD subnetworks were tested, DA often reduced the ongoing cycle frequency, whereas 5HT and Oct both evoked similar accelerations in cycle frequency. However, in the intact pyloric network, both DA and Oct either reduced or did not alter the cycle frequency, whereas 5HT continued to enhance the cycle frequency as before. Our results show that the major target of 5HT in altering the pyloric cycle frequency is the AB neuron, whereas DA's effects on the AB-2xPD subnetwork are critical in understanding its modulation of the cycle frequency. Octopamine's effects on cycle frequency require an understanding of its modulation of the feedback inhibition to the AB-PD group from the lateral pyloric neuron, which constrains the pacemaker group to oscillate more slowly than it would alone. We have thus demonstrated that the relative importance of the different network components in determining the final cycle frequency is not fixed but can vary under different modulatory conditions.'\VSection of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA.10415000http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10415000 http://www.jneurosci.org/cgi/content/full/19/15/6712 http://www.jneurosci.org/cgi/content/abstract/19/15/6712 J Neurosci 199919156712-22.12177147 205/ Pt 18 2002 SepgrlThe locust frontal ganglion: a central pattern generator network controlling foregut rhythmic motor patterns2825-32The frontal ganglion (FG) is part of the insect stomatogastric nervous system and is found in most insect orders. Previous work has shown that in the desert locust, Schistocerca gregaria, the FG constitutes a major source of innervation to the foregut. In an in vitro preparation, isolated from all descending and sensory inputs, the FG spontaneously generated rhythmic multi-unit bursts of action potentials that could be recorded from all its efferent nerves. The consistent endogenous FG rhythmic pattern indicates the presence of a central pattern generator network. We found the appearance of in vitro rhythmic activity to be strongly correlated with the physiological state of the donor locust. A robust pattern emerged only after a period of saline superfusion, if the locust had a very full foregut and crop, or if the animal was close to ecdysis. Accordingly, haemolymph collected at these stages inhibited an ongoing rhythmic pattern when applied onto the ganglion. We present this novel central pattern generating system as a basis for future work on the neural network characterisation and its role in generating and controlling behaviour.'d]Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.*#Ayali, A. Zilberstein, Y. Cohen, N.("22166698 0022-0949 Journal Article J Exp Biollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12177147y (nv78048123$Ayers, J. L. Selverston, A. I.:3Synaptic control of an endogenous pacemaker network2+Action Potentials Animal Ganglia/physiology Lobsters/*physiology *Membrane Potentials Motor Neurons/*physiology Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Neural Inhibition *Periodicity Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiologyay1. The present study consists of an analysis of the coordinating effects of monosynaptic EPSPs and IPSPs on the discharge of the endogenous pacemaker neurons which drive the pyloric motor system of the spiny lobster. The experiments were performed on isolated nervous systems. 2. An analysis of the characteristic phase response curves to both classes of input (fig. 1) shows that the pyloric oscillator possesses the necessary characteristic for entrainment: i.e. a periodically varying sensitivity to synaptic drive. 3. By repetitive stimulation of either input at frequencies near the endogenous frequency of the PD slow wave, it was possible to entrain the discharge of the pacemaker system to the cyclic stimulus (figs. 2b and 3b). The pyloric discharge tends to occur at different characteristic phase relations in response to the two inputs (figs. 2c and 3c), which reflect features of the corresponding phase response curves (fig. 1). 4. It is argued that the periodic sensitivity of these neurons to synaptic input reflects interactions between the synaptically induced currents and the endogenous currents which underlie the slow wave.a 1977 J Physiolc734e 453-61 Using Smart Source Parsing$Ayers, J.L. Selverston, A.I. 1979voMonosynaptic entrainment of an endogenous pacemaker network: A cellular mechanism for von Holst's magnet effectJ Comp Physiol 129 5-1784113825"Ayers, J. Selverston, A. I.XQSynaptic perturbation and entrainment of gastric mill rhythm of the spiny lobsterleAnimal Electric Stimulation Evoked Potentials *Gastrointestinal Motility Lobsters/*physiology Motor Neurons/physiology Nervous System/physiology Nervous System Physiology Neural Inhibition Pylorus/innervation Stomach/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiology *Synaptic Transmission->8The gastric mill rhythm of the lobster stomatogastric ganglion was perturbed with short trains of synaptic input from the inferior ventricular nerve (IVN) through fibers. The stimulus was delivered randomly for phase-response curve analysis or repetitively to examine entrainment. The responses depend on the phase of the stimulus in the endogenous rhythm. The stimulus may alter the internal coordination of the motor pattern. Stimuli that occur during a lateral gastric nerve- anterior lateral nerve-E-neuron (LG-GM-E) burst perturb the burst internally and produce a prolonged LG-GM-E burst, while those that occur during the silent interval between LG-GM-E bursts may evoke a triggered LG-GM-E burst. Spontaneous, prolonged, and triggered LG-GM-E bursts differ in their internal structure as well as the order of burst onsets and offsets. The intercalated triggered LG-GM-E burst delays the occurrence of the subsequent spontaneous LG-GM-E burst, thus strongly resetting the rhythm. These resetting effects have been formalized by phase-response curve analysis. Over limited constraints, cyclic IVN stimuli can entrain the rhythm. Repetitively delivered IVN stimuli have parametric effects on the rhythm that mask the predictive value of phase-response curve analysis for the determination of the phase relations during entrainment.J Neurophysiol 1984511h 113-25"Bal, T. Nagy, F. Moulins, M. 1988d]The pyloric central pattern generator in crustacea: A set of conditional neuronal oscillatorsJ Comp Physiol 163715-727"Bal, T. Nagy, F. Moulins, M. 1990leControle des proprietes neuronales: son importance dans la flexibilite d'un reseau chez les crustacesArch Int Physiol Biochim Bal, T 1991Mecanismes cellulaire impliques dans la reconfiguration fonctionnelle des reseaux neuronaux stomatogastriques des crustaces: Analyse electrophysiologique et pharmacologique par photodissection in situ Bordeaux, France L'Universite de Bordeaux I Ph.D.D94238365"Bal, T. Nagy, F. Moulins, M.\UMuscarinic modulation of a pattern-generating network: control of neuronal propertiesuAnimal Dose-Response Relationship, Drug Ganglia, Invertebrate/cytology/physiology Lobsters Male Membrane Potentials Motor Activity/*physiology Muscarine/*metabolism Nerve Net/drug effects/*physiology Neurons/drug effects/*physiology Oscillometry Oxotremorine/pharmacology Parasympathomimetics/pharmacology *Periodicity Pylorus/*innervation/physiology Support, Non-U.S. Gov't Synapses/physiology p jThe aim of this article is to investigate the cellular mechanisms underlying cholinergic modulation of the pyloric network in the stomatogastric ganglion (STG) of the Cape lobster Jasus Ialandii. Bath application of the muscarinic agonists muscarine, oxotremorine, and pilocarpine on the STG activates a rhythmic pattern from a quiescent pyloric network. The mechanisms of this modulation were investigated on individual pyloric neurons isolated both from synaptic interactions within the network (by photoinactivation of most of the presynaptic neurons and pharmacological blockade of the remaining synapses) and from central inputs (by a sucrose block of the input nerve). All three muscarinic agonists activated bursting and plateau properties of all the neurons comprising the pyloric network. The activation was dose dependent, and was blocked by the muscarinic antagonists atropine, pirenzepine, and scopolamine. The oscillatory behavior triggered by the muscarinic stimulation was specific to each type of pyloric neuron. The isolated neuron AB had the shortest oscillation period and depolarizing phase. The constrictor neurons (LP, PY, IC) were the slowest oscillators, and only oscillated upon hyperpolarizing current injection. Under muscarinic modulation, the individual bursting activities of the isolated pyloric neurons were of the same type as their activities when isolated from the network but modulated by central inputs (Bal et al., 1988). The VD neuron is an exception since it was a rapid oscillator in the latter situation and became a slow oscillator when modulated by a single muscarinic agonist. To determine the relative importance of the muscarinic-dependent bursting properties of the individual pyloric neurons in the operation of the intact network, a progressive reconstruction of the synaptic circuitry was attempted. We found that under certain conditions of muscarinic modulation a new composite pacemaker could be created, composed of the electrically coupled VD, AB, and PD neurons. This can result in the generation of new pyloric patterns that were very sensitive to the membrane potential of individual network neurons. The data also confirmed that, in a rhythmic "pattern-generating network," the pacemaker role may not be definitely attributed to a given neuron but instead could be assigned to other neurons by modulation of their respective oscillatory capabilities. J Neurosci 199414 5 Pt 23019-35"Baldwin, D.H. Graubard, K. 1995wDistribution of fine neurites of stomatogastric neurons of the crab Cancer borealis: Evidence for a structured neuropiliDS J Comp Neurolu 356355-367- !  T"@:73031920@:Barker, D. L. Herbert, E. Hildebrand, J. G. Kravitz, E. A.0*Acetylcholine and lobster sensory neuronesAcetylcholine/biosynthesis/*physiology Acetylcholinesterase/metabolism Acetyltransferases/analysis Aminobutyric Acids/biosynthesis Animal Atropine/pharmacology Axons/enzymology Carbon Isotopes Choline/metabolism Curare/pharmacology Evoked Potentials Ganglia/enzymology Glutamates/metabolism Iontophoresis Lobsters/*physiology Membrane Potentials Neurons/enzymology Neurons, Afferent/physiology Receptors, Cholinergic Synapses/drug effects *Synaptic Transmission J Physiol (Lond) 1972 226e1' 205-29Barker, P.L. Gibson, R. 1977Observations on the feeding mechanism, structure of the gut and digestive physiology of the European lobster, Homarus gammarus (L.) (Decapoda: Nephropidae)nJ Exp Mar Biol Ecolo26297-324.'Barker, D.L. Kushner, P.D. Hooper, N.K., 1979ZTSynthesis of dopamine and octopamine in the crustacean stomatogastric nervous system Brain Res 161 99-113HBBaro, D.J. Cole, C.L. Zarrin, A.R. Hughes, S. Harris-Warrick, R.M. 1994nhShab gene expression in identified neurons of the pyloric network in the lobster stomatogastric ganglionReceptors and Channels2s193-2050*Baro, D.J. Cole, C.L. Harris-Warrick, R.M. 1996haRT-PCR analysis of shaker, shab, shaw, and shal gene expression in single neurons and glial cellsReceptors and Channels4149-1594f`Baro, D.J. Coniglio, L.M. Cole, C.L. Rodriguez, H.E. Lubell, J.K. Kim, M.T. Harris-Warrick, R.M. 1996aLobster shal: Comparison with Drosophila shal and native potassium currents in identified neuronse( J Neurosci16 1689-17010*Baro, D.L. Cole, C.L. Harris-Warrick, R.M. 1996RLThe lobster shaw gene: cloning, sequence analysis and comparison to fly shaw Gene 170267-270haBaro, D.J. Levini, M.T. Kim, M.T. Willms, A.R. Lanning, C.C. Rodriguez, H.E. Harris-Warrick, R.M.a 1997Quantitative single-cell-reverse transcription-PCR demonstrates that A-current magnitude varies as a linear function of shal gene expression in identified stomatogastric neurons J Neurosci17 6597-6610/rlBaro, D. J. Ayali, A. French, L. Scholz, N. L. Labenia, J. Lanning, C. C. Graubard, K. Harris-Warrick, R. M.zMolecular underpinnings of motor pattern generation: differential targeting of shal and shaker in the pyloric motor systemjdAmino Acid Sequence Animal Axons/physiology/ultrastructure Cell Membrane/physiology/ultrastructure Ganglia, Invertebrate/*physiology Lobsters Molecular Sequence Data Neurites/physiology/ultrastructure Neurons/*physiology/ultrastructure Potassium Channels/analysis/genetics/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/physiologyf`The patterned activity generated by the pyloric circuit in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus, results not only from the synaptic connectivity between the 14 component neurons but also from differences in the intrinsic properties of the neurons. Presumably, differences in the complement and distribution of expressed ion channels endow these neurons with many of their distinct attributes. Each pyloric cell type possesses a unique, modulatable transient potassium current, or A-current (I(A)), that is instrumental in determining the output of the network. Two genes encode A-channels in this system, shaker and shal. We examined the hypothesis that cell-specific differences in shaker and shal channel distribution contribute to diversity among pyloric neurons. We found a stereotypic distribution of channels in the cells, such that each channel type could contribute to different aspects of the firing properties of a cell. Shal is predominantly found in the somatodendritic compartment in which it influences oscillatory behavior and spike frequency. Shaker channels are exclusively localized to the membranes of the distal axonal compartments and most likely affect distal spike propagation. Neither channel is detectably inserted into the preaxonal or proximal portions of the axonal membrane. Both channel types are targeted to synaptic contacts at the neuromuscular junction. We conclude that the differential targeting of shaker and shal to different compartments is conserved among all the pyloric neurons and that the channels most likely subserve different functions in the neuron.'Institute of Neurobiology and Department of Biochemistry, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico 00901, USA. djbaro@neurobio.upr.clu.edu10964967http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10964967 http://www.jneurosci.org/cgi/content/full/20/17/6619 http://www.jneurosci.org/cgi/content/abstract/20/17/6619 J Neurosci 200020176619-30.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11566511iLFBaro, D. J. Quinones, L. Lanning, C. C. Harris-Warrick, R. M. Ruiz, M.tmAlternate splicing of the shal gene and the origin of I(A) diversity among neurons in a dynamic motor networkhjcAlternative Splicing/*genetics Animal DNA, Complementary/analysis Female Ganglia, Invertebrate/cytology/*metabolism Lobsters/cytology/genetics/metabolism Membrane Potentials/genetics Molecular Sequence Data Movement/*physiology Nerve Net/cytology/*metabolism Neurons/cytology/*metabolism Oocytes/cytology/metabolism Open Reading Frames/genetics Potassium Channels/*genetics/metabolism Protein Isoforms/genetics/metabolism Pylorus/cytology/innervation/physiology RNA, Messenger/isolation & purification Sequence Homology, Amino Acid Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Xenopus/genetics/metabolismtThe pyloric motor system, in the crustacean stomatogastric ganglion, produces a continuously adaptive behavior. Each cell type in the neural circuit possesses a distinct yet dynamic electrical phenotype that is essential for normal network function. We previously demonstrated that the transient potassium current (I(A)) in the different component neurons is unique and modulatable, despite the fact that the shal gene encodes the alpha-subunits that mediate I(A) in every cell. We now examine the hypothesis that alternate splicing of shal is responsible for pyloric I(A) diversity. We found that alternate splicing generates at least 14 isoforms. Nine of the isoforms were expressed in Xenopus oocytes and each produced a transient potassium current with highly variable properties. While the voltage dependence and inactivation kinetics of I(A) vary significantly between pyloric cell types, there are few significant differences between different shal isoforms expressed in oocytes. Pyloric I(A) diversity cannot be reproduced in oocytes by any combination of shal splice variants.While the function of alternate splicing of shal is not yet understood, our studies show that it does not by itself explain the biophysical diversity of I(A) seen in pyloric neurons.'Institute of Neurobiology, Department of Biochemistry-Medical Sciences Campus, University of Puerto Rico, 201 Boulevard del Valle, San Juan, PR 00901, USA. djbaro@neurobio.upr.clu.edu11566511 2001 Neuroscience 1062 419-32 Using Smart Source Parsing |e(%Nervous System/immunology/*metabolismNervous System/metabolismNervous System/physiologyNeural Conduction Neural Conduction/*physiology$Neural Conduction/drug effects0*Neural Conduction/drug effects/*physiology,)Neural Conduction/drug effects/physiology Neural Conduction/physiologyNeural Inhibition Neural Inhibition/*physiology$Neural Inhibition/drug effects0*Neural Inhibition/drug effects/*physiology,)Neural Inhibition/drug effects/physiology Neural Inhibition/physiology Neural Networks (Computer)Neural Pathways Neural Pathways/*physiologyNeural Pathways/chemistry4.Neural Pathways/cytology/immunology/metabolism(#Neural Pathways/cytology/physiology Neural Pathways/drug effects Neural Pathways/embryology Neural Pathways/physiologyNeurites/drug effectsNeurites/metabolismNeurites/physiology("Neurites/physiology/ultrastructureNeuroglia/ultrastructure($Neuromuscular Junction/*drug effects("Neuromuscular Junction/*physiology0*Neuromuscular Junction/cytology/physiology(#Neuromuscular Junction/drug effects4/Neuromuscular Junction/drug effects/*metabolism4/Neuromuscular Junction/drug effects/*physiology4.Neuromuscular Junction/drug effects/metabolism4.Neuromuscular Junction/drug effects/physiology$!Neuromuscular Junction/embryology$!Neuromuscular Junction/physiology41Neuromuscular Junction/physiology/*ultrastructureNeuronal Plasticity$Neuronal Plasticity/*physiology$Neuronal Plasticity/physiology Neurons, Afferent/*chemistry Neurons, Afferent/*physiology0,Neurons, Afferent/*physiology/ultrastructure0*Neurons, Afferent/drug effects/*physiology Neurons, Afferent/physiology0,Neurons, Afferent/physiology/*ultrastructureNeurons/*chemistry$!Neurons/*chemistry/ultrastructure Neurons/*cytology/physiologyNeurons/*drug effects$ Neurons/*drug effects/physiologyNeurons/*metabolism$Neurons/*metabolism/physiology0-Neurons/*metabolism/physiology/ultrastructure("Neurons/*metabolism/ultrastructureNeurons/*pathologyNeurons/*physiology("Neurons/*physiology/ultrastructureNeurons/*ultrastructureNeurons/chemistry Neurons/chemistry/*physiology,&Neurons/chemistry/cytology/*metabolism("Neurons/classification/*physiology<7Neurons/classification/cytology/drug effects/metabolism4/Neurons/classification/drug effects/*metabolism Neurons/cytology/*metabolism Neurons/cytology/*physiology,)Neurons/cytology/drug effects/*metabolism,(Neurons/cytology/drug effects/metabolism Neurons/cytology/physiology$ Neurons/drug effects/*physiology$Neurons/drug effects/physiology41Neurons/drug effects/physiology/radiation effectsNeurons/enzymology0,Neurons/immunology/metabolism/ultrastructure$Neurons/metabolism/*physiology Neurons/metabolism/physiologyNeurons/physiology("Neurons/physiology/*ultrastructureNeurons/ultrastructureNeuropeptides/*analysis@;Neuropeptides/*analysis/isolation & purification/metabolism@;Neuropeptides/*genetics/immunology/isolation & purificationNeuropeptides/*metabolism,&Neuropeptides/*metabolism/pharmacology Neuropeptides/*pharmacology,&Neuropeptides/*pharmacology/physiologyNeuropeptides/*physiologyNeuropeptides/analysis40Neuropeptides/chemistry/*metabolism/pharmacology(%Neuropeptides/chemistry/*pharmacology("Neuropeptides/genetics/*metabolism4/Neuropeptides/genetics/*metabolism/pharmacology4.Neuropeptides/immunology/metabolism/physiology,&Neuropeptides/pharmacology/*physiologyNeuropil/metabolismNeurosciences/historyNeurosecretion  e41Motor Neurons/drug effects/metabolism/*physiology(%Motor Neurons/drug effects/physiology($Motor Neurons/metabolism/*physiologyMotor Neurons/physiologyMouth/*innervationMouth/innervationMouth/physiology Movement0*Movement Disorders/physiopathology/therapyMovement/*physiologyMovement/physiologymulti-phasic rhythms(#Muscarine/*antagonists & inhibitorsMuscarine/*metabolismMuscimol/metabolismMuscimol/pharmacologyMuscle Contraction$Muscle Contraction/*physiology$Muscle Contraction/drug effects0*Muscle Contraction/drug effects/physiology Muscle Contraction/physiology(%Muscle Fibers, Slow-Twitch/physiologyMuscle Fibers/physiology,)Muscle Relaxation/drug effects/physiologyMuscle Tonus/physiology Muscle, Skeletal/innervation Muscle, Smooth/*innervation Muscle, Smooth/innervation,)Muscle, Smooth/physiology/*ultrastructureMuscles/*drug effectsMuscles/*innervation$ Muscles/*innervation/*physiologyMuscles/*physiologyMuscles/drug effects$!Muscles/drug effects/*innervation$Muscles/drug effects/physiologyMuscles/enzymologyMuscles/innervation$Muscles/innervation/*physiology$Muscles/innervation/physiologyMuscles/physiology Mutagenesis, Site-Directed NephropidaeNephropidae/*metabolismNephropidae/*physiology0,Nephropidae/embryology/*growth & development(#Neprilysin/antagonists & inhibitors Nerve BlockNerve Endings/physiologyNerve Fibers/*physiology,&Nerve Fibers/metabolism/ultrastructureNerve Fibers/physiology Nerve Net(#Nerve Net/*drug effects/*physiologyNerve Net/*embryology$ Nerve Net/*embryology/physiology$Nerve Net/*growth & developmentNerve Net/*metabolismNerve Net/*physiology84Nerve Net/anatomy & histology/metabolism/*physiology0*Nerve Net/cytology/*embryology/*physiology$Nerve Net/cytology/*metabolism$Nerve Net/cytology/*physiology0*Nerve Net/cytology/drug effects/metabolism,)Nerve Net/cytology/embryology/*metabolism Nerve Net/cytology/physiologyNerve Net/drug effects("Nerve Net/drug effects/*metabolism("Nerve Net/drug effects/*physiology$!Nerve Net/drug effects/physiology$Nerve Net/metabolism/physiologyNerve Net/physiologyNerve Regeneration0*Nerve Tissue Proteins/*analysis/immunology$!Nerve Tissue Proteins/*metabolism$Nerve Tissue Proteins/analysis,)Nerve Tissue Proteins/genetics/metabolism$ Nerve Tissue Proteins/physiologyNervous System Physiology(#Nervous System/*anatomy & histologyNervous System/*chemistry Nervous System/*embryology Nervous System/*enzymology84Nervous System/*immunology/metabolism/ultrastructure Nervous System/*metabolism Nervous System/*physiologyNervous System/analysis4.Nervous System/anatomy & histology/*physiology0,Nervous System/chemistry/cytology/embryology(#Nervous System/chemistry/embryologyNervous System/cytology(#Nervous System/cytology/*physiology4/Nervous System/cytology/drug effects/physiology<7Nervous System/cytology/growth & development/metabolism,'Nervous System/drug effects/*physiology82Nervous System/drug effects/immunology/*physiologyNervous System/embryology@;Nervous System/embryology/*growth & development/*metabolism(%Nervous System/enzymology/*metabolism(#Nervous System/growth & development4.Nervous System/growth & development/metabolismZY&Cleland, T.A. Selverston, A.I. 1998XQInhibitory glutamate receptor channels in cultured lobster stomatogastric neuronsJ Neurophysiol766 3189-3196981658754.Clemens, S. Combes, D. Meyrand, P. Simmers, J.Long-term expression of two interacting motor pattern-generating networks in the stomatogastric system of freely behaving lobstero Animal Circadian Rhythm Comparative Study Digestive System/*innervation Electromyography Immobilization Lobsters Membrane Potentials Models, Neurological Motor Neurons/*physiology Muscle, Smooth/innervation Nerve Net/*physiology Reaction Time Support, Non-U.S. Gov'tRhythmic movements of the gastric mill and pyloric regions of the crustacean foregut are controlled by two stomatogastric neuronal networks that have been intensively studied in vitro. By using electromyographic recordings from the European lobster, Homarus gammarus, we have monitored simultaneously the motor activity of pyloric and gastric mill muscles for 300% of their mean duration. However, the duration of activity in the lateral pyloric constrictor muscle, innervated by the unique lateral pyloric (LP) motor neuron, remains unaffected by this perturbation. During this period after gastric perturbation, LP neuron and PY neurons thus express opposite burst-to-period relationships in that LP neuron burst duration is independent of the ongoing cycle period, whereas PY neuron burst duration changes with period length. In vitro the same type of gastro- pyloric interaction is observed, indicating that it is not dependent on sensory inputs. Moreover, this interaction is intrinsic to the stomatogastric ganglion itself because the relationship between the two networks persists after suppression of descending inputs to the ganglion. Intracellular recordings reveal that this gastro-pyloric interaction originates from the gastric MG and LG neurons of the gastric network, which inhibit the pyloric pacemaker ensemble. As a consequence, the pyloric PY neurons, which are inhibited by the pyloric dilator (PD) neurons of the pyloric pacemaker group, extend their activity during the time that PD neuron is held silent. Moreover, there is evidence for a pyloro-gastric interaction, apparently rectifying, from the pyloric pacemakers back to the gastric MG/LG neuron group.J Neurophysiol 1998793r1396-408fn Potentials/*physiology92083593Mulloney, B. Hall, W. M.Neurons with histaminelike immunoreactivity in the segmental and stomatogastric nervous systems of the crayfish Pacifastacus leniusculus and the lobster Homarus americanus>8Animal Brain Chemistry Comparative Study Crayfish/*anatomy & histology Esophagus/innervation Ganglia/*chemistry Histamine/*analysis Immunohistochemistry Interneurons/*chemistry Lobsters/*anatomy & histology Neurotransmitters/analysis Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Thorax/innervationWe used a polyclonal antiserum against histamine to map histaminelike immunoreactivity (HLI) in whole mounts of the segmental ganglia and stomatogastric ganglion of crayfish and lobster. Carbodiimide fixation permitted both HRP-conjugated and FITC-conjugated secondary antibodies to be used effectively to visualize HLI in these whole mounts. Two interneurons that send axons through the inferior ventricular nerve (ivn) and the stomatogastric nerve to the stomatogastric ganglion had strong HLI, both in crayfish and in lobster. These ivn interneurons were known from other evidence to be histaminergic. The neuropil of the stomatogastric ganglion in both crayfish and lobster contained brightly labeled terminals of axons that entered the ganglion from the stomatogastric nerve. No neuronal cell bodies in this ganglion had HLI. Each segmental ganglion contained at least one pair of neurons with HLI. Some neurons in the subesophageal ganglion and in each thoracic ganglion labeled very brightly. Axons of projection interneurons with strong HLI occurred in the dorsal lateral tracts of each segmental ganglion, and sent branches to the lateral neurophils and tract neurophils of each ganglion. All the labeled neurons were interneurons; no HLI was observed in peripheral nerves.Cell Tissue Res  1991 266a1i197-207a&%# <$Bartos, M. Nusbaum, M.P. 1997PJIntercircuit control of motor pattern modulation by presynaptic inhibition J Neurosci17 2247-2256>8Bartos, M. Manor, Y. Nadim, F. Marder, E. Nusbaum, M. P.>8Coordination of fast and slow rhythmic neuronal circuitsRLAnimal Crabs Digestive System/*innervation Gastrointestinal Motility/physiology Interneurons/physiology Neural Pathways/physiology Neurons/*physiology *Periodicity Pylorus/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology Synaptic Transmission/physiology Time FactorsInteractions among rhythmically active neuronal circuits that oscillate at different frequencies are important for generating complex behaviors, yet little is known about the underlying cellular mechanisms. We addressed this issue in the crab stomatogastric ganglion (STG), which contains two distinct but interacting circuits. These circuits generate the gastric mill rhythm (cycle period, approximately 10 sec) and the pyloric rhythm (cycle period, approximately 1 sec). When the identified modulatory projection neuron named modulatory commissural neuron 1 (MCN1) is activated, the gastric mill motor pattern is generated by interactions among MCN1 and two STG neurons [the lateral gastric (LG) neuron and interneuron 1]. We show that, during MCN1 stimulation, an identified synapse from the pyloric circuit onto the gastric mill circuit is pivotal for determining the gastric mill cycle period and the gastric-pyloric rhythm coordination. To examine the role of this intercircuit synapse, we replaced it with a computational equivalent via the dynamic-clamp technique. This enabled us to manipulate better the timing and strength of this synapse. We found this synapse to be necessary for production of the normal gastric mill cycle period. The synapse acts, during each LG neuron interburst, to boost rhythmically the influence of the modulatory input from MCN1 to LG and thereby to hasten LG neuron burst onset. The two rhythms become coordinated because LG burst onset occurs with a constant latency after the onset of the triggering pyloric input. These results indicate that intercircuit synapses can enable an oscillatory circuit to control the speed of a slower oscillatory circuit, as well as provide a mechanism for intercircuit coordination.'|vDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA.10414994http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10414994 http://www.jneurosci.org/cgi/content/full/19/15/6650 http://www.jneurosci.org/cgi/content/abstract/19/15/6650 J Neurosci 199919156650-60.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10879433 >8Bedrov, Y. A. Dick, O. E. Nozdrachev, A. D. Akoev, G. N.b\Method for constructing the boundary of the bursting oscillations region in the neuron modelZSCalcium/physiology Cell Membrane/physiology *Models, Biological Neurons/*physiologyeWe examine the problem of constructing the boundary of bursting oscillations on a parameter plane for the system of equations describing the electrical behaviour of the membrane neuron arising from the interaction of fast oscillations of the cytoplasma membrane potential and slow oscillations of the intracellular calcium concentration. As the boundary point on the parameter plane we consider the values at which the limit cycle of the slow subsystem is tangent to the Hopf bifurcation curve of the fast subsystem. The method suggested for determining the boundary is based on the dissection of the system variables into slow and fast. The strong point of the method is that it requires the integration of the slow subsystem only. An example of the application of the method for the stomatogastric neuron model [Guckenheimer J, Gueron S, Harris-Warrick RM (1993) Philos Trans R Soc Lond B 341: 345-359] is given.'`ZDepartment of Applied Mathematics, Pavlov Institute of Physiology, St. Petersburg, Russia.10879433 Biol Cybern 2000826 493-7.14523066911 2004 JanELong-lasting activation of rhythmic neuronal activity by a novel mechanosensory system in the crustacean stomatogastric nervous system 78-91W~Sensory neurons enable neural circuits to generate behaviors appropriate for the current environmental situation. Here, we characterize the actions of a population (about 60) of bilaterally symmetric bipolar neurons identified within the inner wall of the cardiac gutter, a foregut structure in the crab Cancer borealis. These neurons, called the ventral cardiac neurons (VCNs), project their axons through the crab stomatogastric nervous system to influence neural circuits associated with feeding. Brief pressure application to the cardiac gutter transiently modulated the filtering motor pattern (pyloric rhythm) generated by the pyloric circuit within the stomatogastric ganglion (STG). This modulation included an increased speed of the pyloric rhythm and a concomitant decrease in the activity of the lateral pyloric neuron. Furthermore, 2 min of rhythmic pressure application to the cardiac gutter elicited a chewing motor pattern (gastric mill rhythm) generated by the gastric mill circuit in the STG that persisted for < or =30 min. These sensory actions on the pyloric and gastric mill circuits were mimicked by either ventral cardiac nerve or dorsal posterior esophageal nerve stimulation. VCN actions on the STG circuits required the activation of projection neurons in the commissural ganglia. A subset of the VCN actions on these projection neurons appeared to be direct and cholinergic. We propose that the VCN neurons are mechanoreceptors that are activated when food stored in the foregut applies an outward force, leading to the long-lasting activation of projection neurons required to initiate chewing and modify the filtering of chewed food.'xqDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.4-Beenhakker, M. P. Blitz, D. M. Nusbaum, M. P. 0022-3077 Journal ArticleJ Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14523066*) '(( 83137873"Beltz, B. S. Kravitz, E. A.aNHMapping of serotonin-like immunoreactivity in the lobster nervous systemZSAge Factors Animal Central Nervous System/immunology/physiology Fluorescent Antibody Technique Lobsters/*physiology Nervous System/drug effects/immunology/*physiology *Nervous System Physiology Neurons/physiology Peripheral Nerves/physiology Serotonin/immunology/*physiology Support, U.S. Gov't, P.H.S. 5,7-Dihydroxytryptamine/pharmacologynSerotonin exerts a wide range of physiological actions on many different lobster tissues. To begin the examination of the role of serotonin in lobsters at a cellular level, we have used immunohistochemical methods to search for presumptive serotonergic neurons, their central and peripheral projections, and their terminal fields of arborization. Whole mount preparations of the ventral nerve cord and various peripheral nerve structures have been used for these studies. With these tissues, more than 100 cell bodies have been found that show serotonin-like immunoreactivity. Although a few of the cell bodies are located peripherally (near the pericardial organs, a well known crustacean neurohemal organ), the vast majority are located in central ganglia. Every ganglion in the ventral nerve cord contains at least one immunoreactive cell body. The projections of many of the neurons have been traced, and we have constructed a map of the system of serotonin-immunoreactive cell bodies, fibers, and nerve endings. In addition, a dense plexus of nerve endings showing serotonin-like immunoreactivity surrounds each of the thoracic second roots in the vicinity of groups of peripheral neurosecretory neurons. These peripheral nerve plexuses originate from central neurons of the ventral nerve cord. In some cases we have been able to trace processes from particular central cell bodies directly to the peripheral nerve root plexuses; in other cases we have traced ganglionic neuropil regions to these peripheral endings.i J Neurosci 19833p3f585-602s84241568VOBeltz, B. Eisen, J. S. Flamm, R. Harris-Warrick, R. M. Hooper, S. L. Marder, E.(Serotonergic innervation and modulation of the stomatogastric ganglion of three decapod crustaceans (Panulirus interruptus, Homarus americanus and Cancer irroratus) Animal Chromatography, High Pressure Liquid Crabs/*physiology Electrophysiology Female Gastrointestinal System/*innervation Histocytochemistry Immunologic Techniques Lobsters/*physiology Male Motor Activity Serotonin/*analysis/physiology Support, U.S. Gov't, P.H.S.hThe serotonergic innervation of the stomatogastric ganglion (STG) of three decapod crustacean species, Panulirus interruptus, Homarus americanus and Cancer irroratus, was studied. Immunohistochemical techniques were used to study the distribution of serotonin-like staining in regions of the stomatogastric system in the three species. In C. irroratus and H. americanus, but not in P. interruptus, serotonin- like staining was found in fibres in the stomatogastric nerve and in neuropil regions of the STG. High performance liquid chromatography confirmed the presence of serotonin in STG of C. irroratus and H. americanus, but serotonin was not found in STG of P. interruptus. Electrophysiological experiments showed that the pyloric motor output of the STG of all three species was influenced by bath applications of serotonin. The STG of P. interruptus responded to serotonin concentrations as low as 10-9M; however the STG of the other two species did not respond until serotonin concentrations in excess of 10- 6M were applied. We conclude that serotonin may play a hormonal role in the control of the STG of P. interruptus, but is likely to be a neurotransmitter released by inputs to the STG of H. americanus and C. irroratus.o J Exp Biol 1984 109e 35-54s4-Bem, T. Le Feuvre, Y. Simmers, J. Meyrand, P.,hbElectrical coupling can prevent expression of adult-like properties in an embryonic neural circuittnAction Potentials/physiology Animal Biological Clocks/physiology Computer Simulation Electric Conductivity In Vitro Lobsters Membrane Potentials/physiology Models, Neurological Nerve Net/cytology/*embryology/*physiology Neural Inhibition/*physiology Neural Networks (Computer) Neurons/*physiology Periodicity Support, Non-U.S. Gov't Synaptic Transmission/*physiology Electrical coupling is widespread in developing nervous systems and plays a major role in circuit formation and patterning of activity. In most reported cases, such coupling between rhythmogenic neurons tends to synchronize and enhance their oscillatory behavior, thereby producing monophasic rhythmic output. However, in many adult networks, such as those responsible for rhythmic motor behavior, oscillatory neurons are linked by synaptic inhibition to produce rhythmic output with multiple phases. The question then arises whether such networks are still able to generate multiphasic output in the early stage of development when electrical coupling is abundant. A suitable model for addressing this issue is the lobster stomatogastric nervous system (STNS). In the adult animal, the STNS consists of three discrete neural networks that are comprised of oscillatory neurons interconnected by reciprocal inhibition. These networks generate three distinct rhythmic motor patterns with large amplitude neuronal oscillations. By contrast, in the embryo the same neuronal population expresses a single multiphasic rhythm with small-amplitude oscillations. Recent findings have revealed that adult-like network properties are already present early in the embryonic system but are masked by an as yet unknown mechanism. Here we use computer simulation to test whether extensive electrical coupling may be involved in masking adult-like properties in the embryonic STNS. Our basic model consists of three different adult- like STNS networks that are built of relaxation oscillators interconnected by reciprocal synaptic inhibition. Individual model cells generate slow membrane potential oscillations without action potentials. The introduction of widespread electrical coupling between members of these networks dampens oscillation amplitudes and, at moderate coupling strengths, may coordinate neuronal activity into a single rhythm with different phases, which is strongly reminiscent of embryonic STNS output. With a further increase in coupling strength, the system reaches one of two final states depending on the relative contribution of inhibition and inherent oscillatory properties within the networks: either fully synchronized and dampened oscillations, or a complete collapse of activity. Our simulations indicate that, beginning from either of these two states, the emergence of distinct adult networks during maturation may arise from a developmental decrease in electrical coupling that unmasks preexisting adult-like network properties.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and Centre National de la Recherche Scientifique, Unite Mixte de Recherche 5816, 33405 Talence, France.11784769J Neurophysiol 2002871538-47.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11784769 http://jn.physiology.org/cgi/content/full/87/1/538 http://jn.physiology.org/cgi/content/abstract/87/1/538Benson, J.A. Cooke, I.M. 1984XQDriver potentials and the organization of rhythmic bursting in crustacean ganglia TINS7 85-91P n Potentials/drug effects97461991D=Christie, A. E. Lundquist, C. T. Nassel, D. R. Nusbaum, M. P.`YTwo novel tachykinin-related peptides from the nervous system of the crab Cancer borealisAmino Acid Sequence Animal Crabs/genetics/*metabolism Ganglia, Invertebrate/metabolism Male Molecular Sequence Data Muscle Contraction/drug effects Neuropeptides/genetics/*metabolism/pharmacology Receptors, Tachykinin/antagonists & inhibitors Sequence Homology, Amino Acid Substance P/analogs & derivatives/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tachykinins/metabolismztImmunocytochemical and biochemical studies have indicated the presence of many neuroactive substances in the stomatogastric nervous system (STNS) of the crab Cancer borealis. In electrophysiological studies, many of these substances modulate the motor output of neural networks contained within this system. Previous work in the STNS suggested the presence of neuropeptides related to the invertebrate tachykinin- related peptide (TRP) family. Here we isolate and characterize two novel peptides from the C. borealis nervous system that show strong amino acid sequence identity to the invertebrate TRPs. The central nervous systems of 160 crabs were extracted in an acidified solvent, after which four reversed-phase HPLC column systems were used to obtain pure peptides. A cockroach hindgut muscle contraction bioassay and a radioimmunoassay (RIA) employing an antiserum to locustatachykinin I (Lom TK I) were used to monitor all collected fractions. The amino acid sequences of the isolated peptides were determined by Edman degradation. Mass spectrometry and chemical synthesis confirmed the sequences to be APSGFLGMR-NH2 and SGFLGMR-NH2. APSGFLGMR-NH2 is approximately 20-fold more abundant in the crab central nervous system than is SGFLGMR-NH2. We have named these peptides Cancer borealis tachykinin-related peptide Ia and Ib (CabTRP Ia and Ib), respectively. Both peptides are myoactive in the cockroach hindgut muscle contraction bioassay, with CabTRP Ia being approximately 500 times more potent than CabTRP Ib. RIA performed on HPLC-separated C. borealis stomatogastric ganglion (STG) extract revealed that CabTRP Ia is the only detectable TRP-like moiety in this ganglion. Incubation of synthetic CabTRP Ia with the isolated STG excited the pyloric motor pattern. These effects were suppressed by the broad-spectrum tachykinin receptor antagonist Spantide I. Spantide I had no effect on the actions of the unrelated endogenous peptide proctolin in the STG. There was no consistent influence of CabTRP Ib on the pyloric rhythm. Given its amino acid sequence and minimal biological activity in the crab, CabTRP Ib may be a breakdown product of CabTRP Ia. J Exp Biol 1997 200 Pt 172279-94VXVXZ[[\V]`]aaOOb_ccOOOOO_______gghhhhiiijjjjjddjdddddmmmmmsppqsssqqqqqqqttttuwwwwzz{{kkrrrrrkrkk}{zzzrrr|||||||||||||||xy-,x. + 81095905 Bidaut, M.lePharmacological dissection of pyloric network of the lobster stomatogastric ganglion using picrotoxin0*Acetylcholine/physiology Animal Ganglia/anatomy & histology/*drug effects/physiology Glutamates/physiology GABA/physiology In Vitro Lobsters/*physiology Picrotoxin/*pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/drug effects/physiology Synaptic Transmission/*drug effects 1. Picrotoxin (PTX) (10(-7)-10(-6) M) completely blocked most inhibitory synapses in the pyloric pattern generator of the lobster (Panulirus interruptus) stomatogastric ganglion. The sensitivity of synapses from most classes of identified neurons was examined. Blockade was at least partly reversible with prolonged washing. 2. The synapses from pyloric dilator (PD) neurons were the only inhibitory synapses that picrotoxin failed to block completely. 3. A correlation is derived that brief, fast-rise inhibitory postsynaptic potentials (IPSPs) are picrotoxin sensitive, whereas a slow rounded component of IPSPs from PD neurons is not picrotoxin sensitive. 4. Picrotoxin caused specific changes in the pattern of the motor rhythm produced by the 16-cell pyloric network. This sheds some light on the functional role of particular synapses in the pyloric generator. 5. The endogenously bursting neurons (PD and anterior burster (AB)), which drive the pyloric rhythm, kept a similar burst rate. 6. Under picrotoxin, the pyloric "follower" neurons all moved to later phase relative to the "driver" group. Some normally antagonistic cells, related by reciprocal inhibitor connections, became in-phase. These and other pattern changes could be related to blockade of particular synapses. 7. The pyloric rhythm was still quite recognizable under picrotoxin despite the drastically altered circuitry of the synaptic network. This supports the idea that periodic inhibition from the PD driver neurons plays a primary role in creating the pyloric pattern.J Neurophysiol 1980446 1089-1101w>7Birmingham, J. T. Szuts, Z. B. Abbott, L. F. Marder, E. zsEncoding of muscle movement on two time scales by a sensory neuron that switches between spiking and bursting modescAction Potentials Animal Crabs Digestive System/*innervation In Vitro Movement Muscle, Smooth/*innervation Neurons, Afferent/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Time Factors$The gastropyloric receptor (GPR) neurons of the stomatogastric nervous system of the crab Cancer borealis are muscle stretch receptors that can fire in either a spiking or a bursting mode of operation. Our goal is to understand what features of muscle stretch are encoded by these two modes of activity. To this end, we characterized the responses of the GPR neurons in both states to sustained and rapidly varying imposed stretches. The firing rates of spiking GPR neurons in response to rapidly varying stretches were directly related to stretch amplitude. For persistent stretches, spiking-mode firing rates showed marked adaptation indicating a more complex relationship. Interspike intervals of action potentials fired by GPR neurons in the spiking mode were used to construct an accurate estimate of the time-dependent amplitude of stretches in the frequency range of the gastric mill rhythm (0.05-0.2 Hz). Spike trains arising from faster stretches (similar to those of the pyloric rhythm) were decoded using a linear filter to construct an estimate of stretch amplitude. GPR neurons firing in the bursting mode were relatively unaffected by rapidly varying stretches. However, the burst rate was related to the amplitude of long, sustained stretches, and very slowly varying stretches could be reconstructed from burst intervals. In conclusion, the existence of spiking and bursting modes allows a single neuron to encode both rapidly and slowly varying stimuli and thus to report cycle-by-cycle muscle movements as well as average levels of muscle tension.'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.10561445http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10561445 http://www.jn.org/cgi/content/full/82/5/2786 http://www.jn.org/cgi/content/abstract/82/5/2786J Neurophysiol 19998252786-97.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11341585rBirmingham, J. T. <5Increasing sensor flexibility through neuromodulationEBoth biological and man-made motor control networks require input from sensors to allow for modification of the motor program. Real sensory neurons are more flexible than typical robotic sensors because they are dynamic rather than static. The membrane properties of neurons and hence their excitability can be modified by the presence of neuromodulatory substances. In the case of a sensory neuron, this can change, in a functionally significant way, the code used to describe a stimulus. For instance, extension of the neuron's dynamic range or modification of its filtering characteristics can result. This flexibility has an apparent cost. The code used may be situation- dependent and hence difficult to interpret. To address this issue and to understand how neuromodulation is used effectively in a motor control network, I am studying the GPR2 stretch receptor in the crustacean stomatogastric nervous system. Several different neuromodulatory substances can modify its encoding properties. Comparisons of physiological and anatomical evidence suggest that neuromodulation can be effected both by GPR2 itself and by other neurons in the network. These results suggest that the analog of neuromodulation might be useful for improving sensor performance in an artificial motor control system.'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.a11341585 Biol BullG 2001 200t2 206-10. 12944539 2003 Aug 27}Differential and history-dependent modulation of a stretch receptor in the stomatogastric system of the crab, Cancer borealisNeuromodulators can modify the magnitude and kinetics of the response of a sensory neuron to a stimulus. Six neuroactive substances modified the activity of the gastropyloric receptor 2 (GPR2) neuron of the stomatogastric nervous system (STNS) of the crab Cancer borealis during muscle stretch. Stretches were applied to the gastric mill 9 (gm9) and the cardio-pyloric valve 3a (cpv3a) muscles. SDRNFLRFamide and dopamine had excitatory effects on GPR2. Serotonin, GABA, and the peptide allatostatin-3 (AST) decreased GPR2 firing during stretch. Moreover, SDRNFLRFamide and TNRNFLRFamide increased the unstimulated spontaneous firing rate, while GABA and AST decreased it. The actions of GABA and AST were amplitude and history-dependent. In fully recovered preparations, AST and GABA decreased the response to small amplitude stretches proportionally more than to those evoked by large amplitude stretches. For large amplitude stretches, the effects of AST and GABA were more pronounced as the number of recent stretches increased. The modulators that affected the stretch-induced GPR2 firing rate were also tested when the neuron was operating in a bursting mode of activity. Application of SDRNFLRFamide increased the bursting frequency transiently, while high concentrations of serotonin, AST, and GABA abolished bursting altogether. Together these data demonstrate that the effects of neuromodulators depend upon the previous activity and current state of the sensory neuron.'JDDepartment of Physics, Santa Clara University, Santa Clara, CA, USA.RLBirmingham, J. T. Billimoria, C. P. DeKlotz, T. R. Stewart, R. A. Marder, E."0 0022-3077 Journal articlecJ Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12944539a/ 10 J95301752<6Blitz, D. M. Christie, A. E. Marder, E. Nusbaum, M. P.|vDistribution and effects of tachykinin-like peptides in the stomatogastric nervous system of the crab, Cancer borealisAmino Acid Sequence Animal Crabs/*physiology Electrophysiology Ganglia, Invertebrate/drug effects/*metabolism/physiology Immunohistochemistry Insect Hormones/metabolism/pharmacology Molecular Sequence Data Periodicity Pylorus/drug effects/physiology Stomach/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Tachykinins/*metabolism/pharmacology/*physiology Tissue DistributionnThe rhythmically active pyloric and gastric mill motor patterns in the stomatogastric ganglion of the crab, Cancer borealis, are influenced by modulatory projection neurons whose somata are located primarily in the other ganglia of the stomatogastric nervous system. One of these projection neurons exhibits substance P-like immunolabeling. However, bath application of substance P does not influence these motor patterns. To determine whether a different peptide is responsible for the substance P-like immunolabeling, we studied the presence and physiological effects of the locustatachykinins and the leucokinins, two families of tachykinin-like peptides originally identified in insect nervous systems. Locustatachykinin-like immunolabeling has the same distribution in the stomatogastric nervous system as substance P- like immunolabeling and colocalizes with it in the majority of immunopositive structures. Preincubation of locustatachykinin antibody with substance P, and preincubation of substance P antibody with locustatachykinin, blocks subsequent immunolabeling in the stomatogastric nervous system. In contrast, we found no leucokinin-like immunolabeling in this system. Bath application to the stomatogastric ganglion of individual locustatachykinins or leucokinins excited the pyloric rhythm in a state-dependent manner. Each peptide family had distinct effects on the pyloric rhythm. Thus, both of these tachykinin- like peptide families are likely related to native neuropeptides that influence the pyloric rhythm. Furthermore, a member of the locustatachykinin family is likely to be the source of the previously identified substance P-like immunoreactivity in the stomatogastric nervous system. J Comp Neurol 1995 3542 282-94nghttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/17/13/496597331009"Blitz, D. M. Nusbaum, M. P.B;Motor pattern selection via inhibition of parallel pathwaysf|vAnimal Crabs Esophagus/innervation Ganglia, Invertebrate/*physiology Motor Activity/*physiology Nerve Net/physiology *Neural Inhibition Neural Pathways/physiology Neurons/physiology Neurotransmitters/physiology Oligopeptides/physiology *Periodicity Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synaptic TransmissionMotor pattern selection from a multifunctional neural network often results from direct synaptic and modulatory actions of different projection neurons onto neural network components. Less well documented is the presence and function of interactions among distinct projection neurons innervating the same network. In the stomatogastric nervous system of the crab Cancer borealis, several distinct projection neurons that influence the pyloric and gastric mill rhythms have been studied. These rhythms are generated by overlapping subsets of identified neurons in the stomatogastric ganglion (STG). One of these identified projection neurons is the modulatory proctolin neuron (MPN). We showed previously that MPN stimulation excites the pyloric rhythm by its excitatory actions on STG neurons. In contrast to its excitatory actions on the pyloric rhythm, we have now found that MPN inhibits the gastric mill rhythm. This inhibition does not occur within the STG, but instead results from MPN-mediated inhibition of two previously identified projection neurons within the commissural ganglia. These projection neurons innervate the STG and, via their actions on STG neurons, they elicit the gastric mill rhythm as well as modify the pyloric rhythm in a manner distinct from MPN. By inhibiting these projection neurons, MPN removes excitatory drive to gastric mill neurons and elicits an MPN-specific pyloric rhythm. Motor pattern selection by MPN therefore results from both a direct modulation of STG network activity and an inhibition of competing pathways. J Neurosci 199717134965-75ZSBlitz, D. M. Christie, A. E. Coleman, M. J. Norris, B. J. Marder, E. Nusbaum, M. P.hbDifferent proctolin neurons elicit distinct motor patterns from a multifunctional neuronal networkAnimal Crabs Electrophysiology Ganglia, Invertebrate/anatomy & histology/*cytology/physiology Immunohistochemistry In Vitro Motor Activity Motor Neurons/metabolism/*physiology Nerve Net/anatomy & histology/metabolism/*physiology Neural Pathways Neurotransmitters/metabolism/physiology Oligopeptides/metabolism/*physiology Periodicity Stomach/innervation/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/chemistry/physiology *Synaptic TransmissionDistinct motor patterns are selected from a multifunctional neuronal network by activation of different modulatory projection neurons. Subsets of these projection neurons can contain the same neuromodulator(s), yet little is known about the relative influence of such neurons on network activity. We have addressed this issue in the stomatogastric nervous system of the crab Cancer borealis. Within this system, there is a neuronal network in the stomatogastric ganglion (STG) that produces many versions of the pyloric and gastric mill rhythms. These different rhythms result from activation of different projection neurons that innervate the STG from neighboring ganglia and modulate STG network activity. Three pairs of these projection neurons contain the neuropeptide proctolin. These include the previously identified modulatory proctolin neuron and modulatory commissural neuron 1 (MCN1) and the newly identified modulatory commissural neuron 7 (MCN7). We document here that each of these neurons contains a unique complement of cotransmitters and that each of these neurons elicits a distinct version of the pyloric motor pattern. Moreover, only one of them (MCN1) also elicits a gastric mill rhythm. The MCN7-elicited pyloric rhythm includes a pivotal switch by one STG network neuron from playing a minor to a major role in motor pattern generation. Therefore, modulatory neurons that share a peptide transmitter can elicit distinct motor patterns from a common target network.'|vDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA.10377354http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10377354 http://www.jneurosci.org/cgi/content/full/19/13/5449 http://www.jneurosci.org/cgi/content/abstract/19/13/5449 J Neurosci 199919135449-63.152822772430 2004 Jul 28\VMechanosensory activation of a motor circuit by coactivation of two projection neurons6741-50nIndividual neuronal circuits can generate multiple activity patterns because of the influence of different projection neurons. However, in most systems it has been difficult to identify and assess the relative contribution of all upstream neurons responsible for the activation of any single activity pattern by a behaviorally relevant stimulus. To elucidate this issue, we used the stomatogastric nervous system (STNS) of the crab. The STNS includes the gastric mill (chewing) motor circuit in the stomatogastric ganglion (STG) and no more than 20 projection neurons that innervate the STG. We previously identified at least some (four) of the projection neurons that are activated directly by the ventral cardiac neuron (VCN) system, a population of mechanosensory neurons that activates the gastric mill circuit. Here we show that two of these projection neurons, the previously identified modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2 (CPN2), are necessary and likely sufficient for the initiation/maintenance of the VCN-elicited gastric mill rhythm. Selective inactivation of either MCN1 or CPN2 still enabled a VCN-elicited gastric mill rhythm. However, because MCN1 and CPN2 have different actions on gastric mill neurons, these manipulations resulted in rhythms distinct from each other and from that occurring in the intact system. After removal of both MCN1 and CPN2, VCN stimulation failed to activate the gastric mill rhythm. Selective conjoint stimulation of MCN1 and CPN2, approximating their VCN-elicited activity patterns and firing frequencies, elicited a VCN-like gastric mill rhythm. Thus the VCN mechanosensory system elicits the gastric mill rhythm via its activation of a subset of the relevant projection neurons.M'|vDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA.& Beenhakker, M. P. Nusbaum, M. P. 1529-2401 Journal Article J Neuroscilehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15282277ajb` 95017000B 10(-6) M) were used, and neither Proct. nor Proct. (10(-4) M) influenced the pyloric rhythm. Our results indicate that proctolin is enzymatically degraded and thereby biologically inactivated in the crab nervous system, primarily by extracellularly located aminopeptidase activity. J Neurosci 199414106205-16t95054373$Coleman, M. J. Nusbaum, M. P.HAFunctional consequences of compartmentalization of synaptic inputnAnimal Crabs Dendrites/ultrastructure Electrophysiology Ganglia, Invertebrate/physiology/ultrastructure Male Neural Inhibition Presynaptic Terminals/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/*physiology`ZIntra-axonal recordings of stomatogastric nerve axon 1 (SNAX1) indicate that there are synaptic inputs onto the SNAX1 terminals in the stomatogastric ganglion (STG) of the crab Cancer borealis (Nusbaum et al., 1992b). To determine whether this synaptic input only influenced SNAX1 activity within the STG, we identified the SNAX1 soma in the commissural ganglion (CoG). We found that this neuron has a neuropilar arborization in the CoG and also receives synaptic inputs in this ganglion. Based on its soma location, we have renamed this neuron modulatory commissural neuron 1 (MCN1). While intracellular stimulation of MCN1soma and MCN1SNAX has the same excitatory effects on the STG motor patterns, MCN1 receives distinct synaptic inputs in the STG and CoG. Moreover, the synaptic input that MCN1 receives within the STG compartmentalizes its activity. Specifically, the lateral gastric (LG) neuron synaptically inhibits MCN1SNAX-initiated activity within the STG (Nusbaum et al., 1992b), and while LG did not inhibit MCN1soma- initiated activity in the CoG, it did inhibit these MCN1 impulses when they arrived in the STG. As a result, during MCN1soma-elicited gastric mill rhythms, MCN1soma is continually active in the CoG but its effects are rhythmically inhibited in the STG by LG neuron impulse bursts. One functional consequence of this local control of MCN1 within the STG is that the LG neuron thereby controls the timing of the impulse bursts in other gastric mill neurons. Thus, local synaptic input can functionally compartmentalize the activity of a neuron with arbors in distinct regions of the nervous system. J Neurosci 19941411 Pt 1p6544-52s960850310)Coleman, M. J. Meyrand, P. Nusbaum, M. P.6\VA switch between two modes of synaptic transmission mediated by presynaptic inhibition<5Acetic Acids/pharmacology Action Potentials Animal Crabs Ganglia, Invertebrate/physiology Male Nerve Net/physiology Neural Inhibition/*physiology Presynaptic Terminals/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synaptic Transmission/drug effects/*physiologya\UPresynaptic inhibition reduces chemical synaptic transmission in the central nervous system between pairs of neurons, but its role(s) in shaping the multisynaptic interactions underlying neural network activity are not well studied. We therefore used the crustacean stomatogastric nervous system to study how presynaptic inhibition of the identified projection neuron, modulatory commissural neuron 1 (MCN1), influences the MCN1 synaptic effects on the gastric mill neural network. Tonic MCN1 discharge excites gastric mill network neurons and activates the gastric mill rhythm. One network neuron, the lateral gastric (LG) neuron, presynaptically inhibits MCN1 and is electrically coupled to its terminals. We show here that this presynaptic inhibition selectively reduces or eliminates transmitter-mediated excitation from MCN1 without reducing its electrically mediated excitatory effects, thereby switching the network neurons excited by MCN1. By switching the type of synaptic output from MCN1 and, hence, the activated network neurons, this presynaptic inhibition is pivotal to motor pattern generation.  Nature 1995 378  6556 502-5r>=<j;:9892235704<5Buchholtz, F. Golowasch, J. Epstein, I. R. Marder, E.iHBMathematical model of an identified stomatogastric ganglion neuronAction Potentials/drug effects Animal Crabs/*physiology Electrophysiology Ganglia/cytology/*physiology Ion Channels/drug effects/physiology Models, Biological Neurons/drug effects/*physiology Neurotransmitters/pharmacology Oligopeptides/pharmacology Pylorus/*innervation Sodium Channels/drug effects/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Tetrodotoxin/pharmacologyZS1. The ionic currents in the lateral pyloric (LP) cell of the stomatogastric ganglion (STG) described in the preceding paper of the rock crab Cancer borealis were fit with a set of differential equations that describe their voltage, time, and Ca2+ dependence. The voltage- dependent currents modeled are a delayed rectifier-like current, id; a Ca(2+)-activated outward current, io(Ca); a transient A-like current, iA; a Ca2+ current, iCa; an inwardly rectifying current, ih; and a fast tetrodotoxin (TTX)-sensitive Na+ current, iNa. 2. A single-compartment, isopotential model of the LP cell was constructed from the six voltage- dependent currents, a voltage-independent leak current il, a Ca2+ buffering system, and the membrane capacitance. 3. The behavior of the model LP neuron was compared with that of the biological neuron by simulating physiological experiments carried out in both voltage-clamp and current-clamp modes. The model and biological neurons show similar action-potential shapes, durations, steady-state current-voltage (I-V) curves, and respond to injected current in a comparable way.cJ Neurophysiol 1992672L 332-40ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10788671)<6Cabirol-Pol, M. J. Mizrahi, A. Simmers, J. Meyrand, P.Combining laser scanning confocal microscopy and electron microscopy to determine sites of synaptic contact between two identified neurons,%Animal Female Fluorescent Dyes Ganglia, Invertebrate/cytology Horseradish Peroxidase Immunohistochemistry Isoquinolines Lobsters Male Microscopy, Confocal/*methods Microscopy, Immunoelectron/*methods Microtomy Neurons/*ultrastructure Rhodamines Support, Non-U.S. Gov't Synapses/*ultrastructureHere we report a double labelling method for correlative confocal and electron microscopy (EM) which allows selective characterisation of structural relationships between two single identified neurons in the same preparation. Using the lobster stomatogastric nervous system, we labelled pairs of identified, synaptically-connected neurons by intracellular injection of Lucifer Yellow (LY) in one neuron and a mixture of Rhodamine (Rdh) and Horseradish Peroxidase (HRP) in its partner. First, whole-mounts of LY- and Rdh-stained neurons were visualized using laser scanning confocal microscopy (LSCM) in order to isolate neuropilar regions of possible synaptic contact. Second, after conventional treatment for electron microscopy (LY was revealed with immunogold and HRP with DAB), areas of close appositions were viewed in EM. This technique allowed us to determine all the regions of close contact between two cells, and then to use electron microscopy to determine the presence or absence of synaptic contact within each of these restricted areas. These techniques enabled us to show that there were few areas of apposition and that only an extremely small proportion of these areas was in fact regions of synaptic contact between the two labelled neurons.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and CNRS UMR 5816, Avenue des Facultes, 33405, Talence, France.10788671J Neurosci Methods 2000972175-81. Caine, E.A. 1975^WFeeding and masticatory structures of six species of the crayfish (Decapoda, Astacidae)Forma et Functio8 49-66Calabrese, R. L. 1991The center cannot hold Curr BiolE1t3w185-187m'xqDepartment of Biology Emory University 1510 Clifton Road, Atlanta, Georgia 30322, USA. rcalabre@biology.emory.edue991424418062 1998 DecZTCellular, synaptic, network, and modulatory mechanisms involved in rhythm generation 710-7iThe membrane properties and the synaptic interactions of individual neurons, as well as the interactions between neuronal networks, all contribute to the formation of the complex patterns of activity that underlie rhythmic motor patterns and slow-wave sleep rhythms. These properties and interactions are potential points of modulation for further refining network output. Recent work illustrates the range of these properties and interactions and suggests how they may be modulated.r'zsDepartment of Biology, Emory University, 1510 Clifton Road, Atlanta, Georgia 30322, USA. rcalabre@biology.emory.edueCalabrese, R. L.@:99116055 0959-4388 Journal Article Review Review, TutorialCurr Opin NeurobioltAnimal Nerve Net/*physiology Neurons/*physiology Neurotransmitters/*physiology *Periodicity Support, U.S. Gov't, P.H.S. Synapses/*physiologyjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9914244Calabrese, R. L."Taking the lead from a modelAnimal Crabs/*physiology Ganglia, Invertebrate/*physiology Gastrointestinal Motility/*physiology Gastrointestinal System/*innervation *Models, Neurological Motor Neurons/*physiology Muscle Contraction Muscle, Smooth/innervation :4It is rare these days that theory leads experiment in the biological sciences, but it still happens. A recent study has experimentally confirmed the predictions of a model aimed at explaining how neural networks interact to produce the coordinated patterns of motor activity necessary for effective behavior.'xqDepartment of Biology Emory University 1510 Clifton Road, Atlanta, Georgia 30322, USA. rcalabre@biology.emory.edu10508603 Curr Biol 1999918R680-3.{http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10508603 http://www.biomednet.com/article/bb9r10871864592+Callaway, J. C. Masinovsky, B. Graubard, K.f`Co-localization of SCPB-like and FMRFamide-like immunoreactivities in crustacean nervous systemsAntibodies, Monoclonal/diagnostic use Crabs/*analysis Nervous System/analysis Neuropeptides/*analysis Species Specificity Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.sLFA monoclonal antibody to the molluscan small cardioactive peptide SCPB and a polyclonal antibody to FMRFamide were used to localize antigens in the stomatogastric nervous system and brain of two species of Cancer. Both antibodies labeled cell bodies, axons, and neuropilar processes in the brain and in the stomatogastric nervous system. All of the SCPB immunoreactive neurons were co-labeled with antibody to FMRFamide. However, antibody to FMRFamide labeled additional neurons of the commissural ganglion and the brain that were not immunoreactive to the monoclonal SCPB antibody. Brain Resr 1987 405o2"295-304 DCA@B?477096046$Calvin, W. H. Hartline, D. K.arkRetrograde invasion of lobster stretch receptor somata in control of firing rate and extra spike patterningAnimal Electric Stimulation Electrophysiology Lobsters/*physiology Mechanoreceptors/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.e1. Extra spikes may be interleaved in the otherwise rhythmic discharge pattern of the lobster stretch receptor neuron, about 2 ms after an expected spike. A constant input to the neuron is maintained by injecting current intrasomatically. The axon recovers its excitability while the retrograde invasion of the soma and dendrites is still in progress, which provide electrotonic currents to reexcite the axon. 2. While extra spikes in the axon often arise from a prolonged somatic (dendritic?) depolarization, they may also arise from a delayed retrograde invasion of the soma. 3. Failure of retrograde invasion may cause a sudden jump in the rate of rhythmic discharge, demonstrating the role of the soma-dendritic afterhyperpolarization in the regulation of rhythmic firing rate. 4. The history of repetitive firing is often important. Because extra spikes often first appear during a decline in firing rate, turning on and then off, an additional current may sometimes activate the extra spike mode, thus doubling the resting firing rate in a metastable manner. Another mestastable state is associated with failure of retrograde invasion. 5. Extra spikes augment the high end of the frequency-current curve in some receptor neurons; in other cases, the extra spikes are seen only at low rhythmic firing rates, dropping out as current reaches intermediate values to create a paradoxical negative-sensitivity region (decline in total spikes per second with increasing current). 6. The results suggest that both the extent and the speed of active retrograde invasion of the soma and dendrites are likely candidates for pathophysiological mechanisms, since they may control whether extra spikes are generated.J Neurophysiol 1977401u 106-184-Cardi, P. Nagy, F. Cazaletz, J.R. Moulins, M. 1990Multimodal distribution and discontinuous variation in period of interacting oscillators in the crustacean stomatogastric nervous systemJ Comp Physiol 167 23-41A Cardi, P. 1991Controle modulateur rhythmique d'un reseau du systeme nerveux stomatogastrique des crustaces: Etude anatomique, electrophysiologique et pharmacologique Bordeaux, France University of Bordeaux Ph.D.A95016938Cardi, P. Nagy, F.A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. III. Rhythmic control of the pyloric CPGd]Animal Electric Stimulation Female Ganglia, Invertebrate/*physiology Gastric Emptying/physiology Laterality/physiology Lobsters/*physiology Male Membrane Potentials/physiology Mouth/*innervation Nerve Net/*physiology Neural Inhibition/*physiology Neurons/physiology Pyloric Antrum/*physiology Support, Non-U.S. Gov't Synaptic Transmission/physiologyo1. Two modulatory neurons, P and commissural pyloric (CP), known to be involved in the long-term maintenance of pyloric central pattern generator operation in the rock lobster Homarus gammarus, are members of the commissural pyloric oscillator (CPO), a higher-order oscillator influencing the pyloric network. 2. The CP neuron was endogenously oscillating in approximately 30% of the preparations in which its cell body was impaled. Rhythmic inhibitory feedback from the pyloric pacemaker anterior burster (AB) neuron stabilized the CP neuron's endogenous rhythm. 3. The organization of the CPO is described. Follower commissural neurons, the F cells, and the CP neuron receive a common excitatory postsynaptic potential from another commissural neuron, the large exciter (LE). When in oscillatory state, CP in turn excites the LE neuron. This positive feedback may maintain long episodes of CP oscillations. 4. The pyloric pacemaker neurons follow the CPO rhythm with variable coordination modes (i.e., 1:1, 1:2) and switch among these modes when their membrane potential is modified. The CPO inputs strongly constrain the pyloric period, which as a result may adopt only a few discrete values. This effect is based on mechanisms of entrainment between the CPO and the pyloric oscillator. 5. Pyloric constrictor neurons show differential sensitivity from the pyloric pacemaker neurons with respect to the CPO inputs. Consequently, their bursting period can be a shorter harmonic of the bursting period of the pyloric pacemakers neurons. 6. The CPO neurons seem to be the first example of modulatory gating neurons that also give timing cues to a rhythmic pattern generating network.J Neurophysiol 19947162503-16"Carlton, C.E. Schmitz, E.H.a 1989PAnatomy of the extrinsic gut musculature of Gammarus minus (Crustacea Amphipoda),: J Morphol 200r 87-92d95370934 Casasnovas, B. Meyrand, P.ZSFunctional differentiation of adult neural circuits from a single embryonic networkAnimal Digestive System/embryology/innervation *Fetal Development Lobsters/*embryology Motor Activity/physiology Nerve Net/*embryology Nervous System/*embryology Neural Pathways/embryology Neuromuscular Junction/embryology Periodicity Support, Non-U.S. Gov'tThe stomatogastric nervous system (STNS) of adult lobsters and crabs generates a number of different rhythmic motor patterns which control different regional movements of the foregut. Since these output patterns are generated by discrete neural networks that, in the adult, are well characterized in terms of synaptic and cellular properties, this system constitutes an ideal model for exploring the mechanisms underlying the ontogeny of neural network organization. The foregut and its rhythmic motor patterns were studied in in vitro STNS nerve-muscle preparations of the embryo and different larval stages of the lobster Homarus gammarus. The development of Homarus comprises a long embryonic stage in ovo followed by three pelagic larval stages prior to the onset of benthic life. During these stages the foregut itself develops slowly from a simple ectodermal invagination that occurs in the embryo. During successive larval stages it progressively acquires all the specialized structures and shape of the adult foregut. In contrast, the STNS is morphologically recognizable at early embryonic stages. In all recorded stages the STNS spontaneously expresses rhythmic motor activity. During development, this activity is progressively restructured, beginning with a single rhythmic motor pattern in the embryo where all the stomodeal muscles are strongly coordinated. In subsequent stages, however, this single pattern is progressively subdivided to give rise eventually to the three discrete rhythmic motor patterns characteristic of the adult STNS. Our data suggest that rather than a dismantling of redundant embryonic and larval neural networks, the different adult networks emerge as a progressive partitioning of discrete circuits from a single embryonic network. J Neurosci 19951585703-18IH .G4FE87310635:3Cazalets, J. R. Cournil, I. Geffard, M. Moulins, M.nhbSuppression of oscillatory activity in crustacean pyloric neurons: implication of GABAergic inputsAnimal Electric Stimulation Electrophysiology GABA/analysis Histocytochemistry Lobsters Muscimol/metabolism Neurons/*physiology Pyloric Antrum/*innervation Support, Non-U.S. Gov't Tetrodotoxin/pharmacology Generation of rhythmic pyloric motor output in the crustacean stomatogastric ganglion results from synaptic connections and cellular properties of a 14-cell network of pyloric neurons. These cellular properties are under the influences of modulatory inputs, which act, for the most part, in an activating mode, i.e., they enhance the bursting properties of the pyloric neurons and/or their ability to express their regenerative properties. Here we attempt to demonstrate that the pyloric motor output is also under the control of suppressive afferent inputs that are able to stop the pyloric rhythm in a long- lasting manner. Immunohistochemistry, using GABA antibodies, indicates that GABAergic-like fibers are present in both the stomatogastric ganglion and its afferent nerve. Bath-applied GABA suppresses spontaneous pyloric rhythmic activity. This is due to an inability of the pyloric pacemakers to express their bursting properties. The suppressive effect of GABA is blocked by picrotoxin and mimicked by muscimol. Isolating the pyloric neurons from all descending spiking influences with tetrodotoxin demonstrates that exogenously applied GABA acts directly on the pyloric neurons. To confirm the existence of a physiological suppressive system for the pyloric motor pattern, we show that the stimulation of an afferent nerve, known to contain GABA-like fibers, also causes the cessation of rhythmic activity and the inability of the pyloric neurons to express their bursting properties.m J Neurosci 19877u9o2884-93i88123180*$Cazalets, J. R. Nagy, F. Moulins, M.rkSuppressive control of a rhythmic central pattern generator by an identified modulatory neuron in crustaceafAction Potentials Animal *Biological Clocks Ganglia/cytology/physiology In Vitro Lobsters/*physiology Motor Neurons/*physiology Pylorus/innervation/physiology Support, Non-U.S. Gov't The activity of the 14 neuron network which organizes the pyloric motor rhythm in the stomatogastric ganglion of the lobster, Homarus gammarus, is controlled by neuromodulatory inputs which have been described as having mainly 'permissive' effects. By contrast, here we identify a neuron, the pyloric suppressor (PS) neuron which exerts a 'suppressive' effect on the pyloric activity. We show that PS neuron discharge can terminate in a long-lasting manner, spontaneous pyloric rhythmic activity. Its effect results from a direct suppression of the endogenous ability of the pyloric pacemaker neurons to produce rhythmic bursts of action potentials. Thus the output of the pyloric neuronal network appears to be finely tuned by neuromodulatory influences having opposite effects.n Neurosci Lettc 1987813r 267-7290155415*$Cazalets, J. R. Nagy, F. Moulins, M.Suppressive control of the crustacean pyloric network by a pair of identified interneurons. II. Modulation of neuronal propertieswAnimal Brain/cytology/*physiology Digestive System/*innervation Electrophysiology Interneurons/*physiology Lobsters/*physiology Nerve Net/cytology/*physiology Nervous System/*physiology *Nervous System Physiology Pylorus Support, Non-U.S. Gov't Time Factorsu4.In the lobster Homarus, the 2 identified PS neurons have a strong suppressive modulatory effect on the activity of the pyloric network in the STG (Cazalets et al., 1990). In the present paper, we consider the effects of PS on individual pyloric neurons isolated from their partners in the network by cell photoinactivation and synaptic blockade. Three types of PS action are described: (1) a transient, EPSP- mediated depolarization of the PD, VD, and AB neurons; (2) a long- lasting hyperpolarization concomitant with a loss of oscillatory properties in the PD and LP neurons; (3) a long-lasting depolarization without modification of oscillatory properties in the PY and IC neurons. The various effects of PS on isolated pyloric cells were consistent with the overall effects of PS on the intact pyloric network. J Neurosci 1990102 458-6890155414*$Cazalets, J. R. Nagy, F. Moulins, M.~Suppressive control of the crustacean pyloric network by a pair of identified interneurons. I. Modulation of the motor pattern,&Animal Brain/cytology/*physiology Digestive System/*innervation Electrophysiology Ganglia/physiology Interneurons/*physiology Lobsters/*physiology Motor Activity/*physiology Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Pylorus Support, Non-U.S. Gov't Time FactorsA pair of identified neuromodulatory neurons, the pyloric suppressor (PS) neurons, can individually and strongly modify the activity of the pyloric network in the stomatogastric nervous system of the lobster Homarus gammarus. The PS neurons are identified by the location of their somata in the inferior ventricular nerve, their axonal projections, and their effects on pyloric network activity in vitro. Discharge of a PS neuron evokes large EPSPs in the pyloric dilator (PD) neurons and a long-lasting cessation of rhythmic activity in the neurons that control movements of the pyloric filter: PD, lateral pyloric (LP), and pyloric (PY). This cessation of rhythmic activity can outlast by several 10s of seconds a brief discharge of PS lasting only a few seconds. The different neurons of the pyloric filter do not exhibit the same sensitivity to the suppressive effects of PS, with the LP neuron being the most sensitive. Tonic discharge in PS induces graded alterations in the pyloric pattern, depending on its firing frequency. At low (less than 5 Hz) discharge frequencies, PS provokes changes in phase relationships and duration of bursting in pyloric neurons. A slight increase in PS frequency suppresses the rhythmic activity of some pyloric neurons, resulting in a switch from a triphasic to a biphasic pattern. At higher (greater than 10 Hz) PS firing frequencies, rhythmic activity in all the pyloric neurons, including the pacemakers (PD, anterior burster), is abolished, except in cells (ventricular dilator, inferior cardiac) controlling the pyloric valve. We conclude that a central pattern generator is not only subject to activating modulatory control, but may also be the target of suppressive inputs that are themselves able to provoke functional reconfigurations of the network.  J Neurosci 1990102t 448-57*#Chabaud, F. Friedi, M. Reichert, H. 1991JDNeuronal development of the crustacean stomatogastric nervous system Penzlin, H. Elsner, N.(!Synapse, Transmission, Modulatione Thieme Verlag 495g6532 "Blitz, D. M. Nusbaum, M. P. NGDistinct functions for cotransmitters mediating motor pattern selectionHAAnimal Crabs/*physiology GABA/pharmacology Ganglia, Invertebrate/drug effects/physiology Motor Neurons/drug effects/physiology Nerve Net/drug effects/physiology Neurotransmitters/physiology Oligopeptides/physiology Pyloric Antrum/innervation Stomach/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Motor patterns are selected from multifunctional networks by selective activation of different projection neurons, many of which contain multiple transmitters. Little is known about how any individual projection neuron uses its cotransmitters to select a motor pattern. We address this issue by using the stomatogastric ganglion (STG) of the crab Cancer borealis, which contains a neuronal network that generates multiple versions of the pyloric and gastric mill motor patterns. The functional flexibility of this network results mainly from modulatory inputs it receives from projection neurons that originate in neighboring ganglia. We demonstrated previously that the STG motor pattern selected by activation of the modulatory proctolin neuron (MPN) results from direct MPN modulation of the pyloric rhythm and indirect MPN inhibition of the gastric mill rhythm. The latter action results from MPN inhibition of projection neurons that excite the gastric mill rhythm. These projection neurons are modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2 (CPN2). MPN excitation of the pyloric rhythm is mimicked by bath application of proctolin, its peptide transmitter. Here, we show that MPN uses only its small molecule transmitter, GABA, to inhibit MCN1 and CPN2 within their ganglion of origin. We also demonstrate that MPN has no proctolin- mediated influence on MCN1 or CPN2, although exogenously applied proctolin directly excites these neurons. Thus, motor pattern selection occurs during MPN activation via proctolin actions on the STG network and GABA-mediated actions on projection neurons in the commissural ganglia, demonstrating a spatial and functional segregation of cotransmitter actions.'|vDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA.10436035http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10436035 http://www.jneurosci.org/cgi/content/full/19/16/6774 http://www.jneurosci.org/cgi/content/abstract/19/16/6774 J Neurosci 199919166774-83.156019442450 2004 Dec 15\UDifferent sensory systems share projection neurons but elicit distinct motor patterns11381-90Considerable research has focused on issues pertaining to sensorimotor integration, but in most systems precise information remains unavailable regarding the specific pathways by which different sensory systems regulate any single central pattern-generating circuit. We address this issue by determining how two muscle stretch-sensitive neurons, the gastropyloric receptor neurons (GPRs), influence identified projection neurons that regulate the gastric mill circuit in the stomatogastric nervous system of the crab and then comparing these actions with those of the ventral cardiac neuron (VCN) mechanosensory system. Here, we show that the GPR neurons activate the gastric mill rhythm in the stomatogastric ganglion (STG) via their excitation of two identified projection neurons, modulatory commissural neuron 1 (MCN1) and commissural projection neuron 2 (CPN2), in the commissural ganglion. Support for this conclusion comes from the ability of the modulatory proctolin neuron (MPN), a projection neuron that suppresses the gastric mill rhythm via its inhibitory actions on MCN1 and CPN2, to inhibit the GPR-elicited gastric mill rhythm. Selective elimination of MCN1 and CPN2 access to the STG also prevents GPR activation of this rhythm. The VCN neurons also elicit the gastric mill rhythm by coactivating MCN1 and CPN2, but the GPR-elicited gastric mill rhythm is distinct. These distinct rhythms are likely to result partly from different MCN1 activity levels under these two conditions and partly from the presence of additional GPR actions in the STG. These results support the hypothesis that different sensory systems differentially regulate neuronal circuit activity despite their convergent actions on a single subpopulation of projection neurons.'|vDepartment of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6074, USA.4-Blitz, D. M. Beenhakker, M. P. Nusbaum, M. P. 1529-2401 Journal Article J Neuroscilehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15601944Bohm, H. 1995VActivity of the stomatogastric system in free-moving crayfish, Orconectes limosus Raf.?QZoologyl99247-257-4-Bohm, H. Eitner, E. Messai, E. Heinzel, H. G. 1997,%Das nervensystem des flusskrebsmagens  Biologie in inserer Zeit. 27 56-64("Bohm, H. Messai, E. Heinzel, H. G. 1997LActivity of command fibres in free-ranging crayfish, Orconectes limosus Raf.5GNaturwissenschaften\84408-410lsZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10212401>8Withers, M. D. Kennedy, M. B. Marder, E. Griffith, L. C.Characterization of calcium/calmodulin-dependent protein kinase II activity in the nervous system of the lobster, Panulirus interruptushpjAmino Acid Sequence Animal Ca(2+)-Calmodulin Dependent Protein Kinase/*analysis/genetics Gene Expression Regulation, Enzymologic/physiology Lobsters/*enzymology Molecular Sequence Data Nervous System/*enzymology Phosphorylation Polymerase Chain Reaction Precipitin Tests Species Specificity Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.d]Nervous system tissue from Panulirus interruptus has an enzyme activity that behaves like calcium/calmodulin-dependent protein kinase II (CaM KII) This activity phosphorylates known targets of CaM KII, such as synapsin I and autocamtide 3. It is inhibited by a CaM KII-specific autoinhibitory domain peptide. In addition, this lobster brain activity displays calcium-independent activity after autophosphorylation, another characteristic of CaM KII. A cDNA from the lobster nervous system was amplified using polymerase chain reaction. The fragment was cloned and found to be structurally similar to CaM KII. Serum from rabbits immunized with a fusion protein containing part of this sequence immunoprecipitated a CaM KII enzyme activity and a family of phosphoproteins of the appropriate size for CaM KII subunits. Lobster CaM KII activity is found in the brain and stomatogastric nervous system including the commissural ganglia, commissures, stomatogastric ganglion and stomatogastric nerve. Immunoblot analysis of these same regions also identifies bands at an apparent molecular weight characteristic of CaM KII.'\VVolen Center, Brandeis University, Waltham, MA 02254, USA. mwithers@volen.brandeis.edu10212401Invert Neurosci 199834335-45.MLK.OJ93058830Chiba, C. Tazaki, K.d^Glutamatergic motoneurons in the stomatogastric ganglion of the mantis shrimp Squilla oratoria"Acetylcholine/physiology Animal Electrophysiology Ganglia/*physiology/ultrastructure Glutamates/*physiology Iontophoresis Membrane Potentials/physiology Motor Neurons/*physiology Neuromuscular Junction/physiology Neurotransmitters/physiology Shrimp/*physiology Support, Non-U.S. Gov't1. Transmitters of motoneurons in the stomatogastric ganglion (STG) of Squilla were identified by analyzing the excitatory neuromuscular properties of muscles in the posterior cardiac plate (pcp) and pyloric regions. 2. Bath and iontophoretic applications of glutamate produce depolarizations in these muscles. The pharmacological experiments and desensitization of the junctional receptors elucidate the glutamatergic nature of the excitatory junctional potentials (EJPs) evoked in the constrictor and dilator muscles. The reversal potentials for the excitatory junctional current (EJC) and for the glutamate-induced current are almost the same. 3. Some types of dilator muscle show sensitivity to both glutamate and acetylcholine (ACh) exogenously applied. The pharmacological evidence and desensitization of the junctional receptors indicate the glutamatergic nature of neuromuscular junctions in these dually sensitive muscles. The reversal potentials for the EJC and for the ACh-induced current are not identical. 4. Glutamate is a candidate as an excitatory neuro-transmitter at the neuromuscular junctions which the STG motoneurons named PCP, PY, PD, LA and VC make with the identified muscles. Kainic and quisqualic acids which act on glutamate receptors are potent excitants of these muscles. Extrajunctional receptors to ACh are present in two types of the muscle innervated by LA and VC. 5. Neurotransmitters used by the STG motoneurons of stomatopods are compared to those of decapods..J Comp Physiol [A] 1992 170x6y 773-869505364160Christie, A. E. Hall, C. Oshinsky, M. Marder, E.leBuccalin-like and myomodulin-like peptides in the stomatogastric ganglion of the crab Cancer borealislAmino Acid Sequence Animal Crabs/chemistry/*genetics Digestive System/innervation Ganglia, Invertebrate/physiology Immunohistochemistry Molecular Sequence Data Neuropeptides/*genetics/immunology/isolation & purification Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.d J Exp Biol 1994 193l 337-43f`http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.cob.org.uk/JEB/198/01/jeb9613.html0oF?Christie, A. Baldwin, D. Turrigiano, G. Graubard, K. Marder, E.eImmunocytochemical localization of multiple cholecystokinin-like peptides in the stomastogastric nervous system of the crab Cancer borealissThree anti-cholecystokinin antibodies were used to label the stomatogastric nervous system of the crab Cancer borealis. Labeled tissues were examined as whole mounts using laser scanning confocal microscopy. Although each of the anti-cholecystokinin antibodies labeled a variety of structures within the stomatogastric nervous system (including somata, fibers and neuropil), the pattern of labeling produced by each antibody was distinct. These results indicate that there is a family of cholecystokinin-like molecules that are differentially distributed among a subpopulation of the neurons in the stomatogastric nervous system of Cancer borealis. 1995 J Exp Biol 198 1m 263-71 Using Smart Source Parsingf`http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.cob.org.uk/JEB/198/12/jeb9908.html0r("Christie, A. Skiebe, P. Marder, E.XRMatrix ofneuromodulators in neurosecretory structures of the crab, Cancer borealisb\The crustacean stomatogastric ganglion, which is situated in the ophthalmic artery, can be modulated by both intrinsically released molecules and hormones. In the crab Cancer borealis, over a dozen neuroactive compounds have been identified in the input axons that project into the stomatogastric neuropil. However, little is known about the modulator content of the two major neurohemal organs, the sinus glands and the pericardial organs, in this crab. We now report the results of a series of immunocytochemical experiments designed to identify putative neurohormones in these tissues. We find that the majority of modulators present in the input axons of the stomatogastric ganglion are also present in at least one of the neurohemal organs. Specifically, allatostatin-like, buccalin-like, cholecystokinin-like, FLRFamide-like, GABA-like, locustatachykinin-like, myomodulin-like, proctolin-like, red pigment concentrating hormone-like and serotonin- like immunoreactivities are all present in both the stomatogastric neuropil and at least one of the neurohemal organs. Thus, these substances are likely to serve a dual role as both local and hormonal modulators of the stomatogastric network. Two other substances, - pigment dispersing hormone and crustacean cardioactive peptide, are not present in the stomatogastric neuropil, but -pigment dispersing hormone immunoreactivity is present in the sinus glands and crustacean cardioactive peptide immunoreactivity is present in the pericardial organs. It is likely that crustacean cardioactive peptide exerts its influence on the stomatogastric neural circuit via hormonal pathways. Double-labeling experiments show that the patterns of modulator co- localization present in the stomatogastric neuropil are different from those in the neurosecretory organs, suggesting that few rules of co- localization hold across these tissues. 1995 J Exp Biol 19812 2431-9 Using Smart Source Parsing97195750<6Christie, A. E. Baldwin, D. H. Marder, E. Graubard, K.|vOrganization of the stomatogastric neuropil of the crab, Cancer borealis, as revealed by modulator immunocytochemistry>7Animal Cholecystokinin/analysis Crabs/*metabolism Fluorescent Antibody Technique, Indirect Ganglia, Invertebrate/cytology/*metabolism Neurotransmitters/*analysis Oligopeptides/analysis Peptide Fragments/analysis Rabbits Serotonin/analysis Substance P/analysis Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.eWe used antibodies to a number of neuromodulatory substances, including serotonin, FLRF amide, red pigment-concentrating hormone, substance P, proctolin and cholecystokinin, to investigate the distribution of molecules similar to these substances in the stomatogastric ganglion of the crab, Cancer borealis. No immunoreactivity was seen in the region of the cell bodies that surrounds the neuropil and little was found in the core of the neuropil (where the primary neurites of the intrinsic neurons occupy most of the space). Instead, modulator immunolabel was densely packed in the more peripheral portion of the neuropil that surrounded the core. Within this peripheral neuropil, profiles appeared quite uniformly distributed. Double-labeling showed that there were limited differences in distribution between the labels examined in our study. The only immunolabeled structures that showed a distinct differential distribution within the stomatogastric neuropil were a population of >/=10 microm varicosities that arose from a pair of input fibers that we termed the large varicosity fibers. These varicosities were immunolabelled by antisera for three different peptides. Taken collectively, these data shows that there is a stereotyped distribution of modulator immunoreactivity within the crab stomatogastric neuropil. However, this segregation is more rudimentary than that reported for the intrinsic stomatogastric neurons.nCell Tissue Reso 1997 288r1s 135-48XZV<W 96033755& Cleland, T. A. Selverston, A. I.voGlutamate-gated inhibitory currents of central pattern generator neurons in the lobster stomatogastric ganglionAnimal Calcium/metabolism Cells, Cultured Central Nervous System/cytology/*physiology Electrophysiology Excitatory Amino Acid Agonists/pharmacology Excitatory Amino Acid Antagonists/pharmacology Extracellular Space/metabolism Ganglia, Invertebrate/cytology/*physiology Glutamic Acid/*physiology Lobsters/*physiology Neural Inhibition/*physiology Neurons/physiology Periodicity Receptors, Glutamate/physiology Stomach/*innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Inhibitory glutamatergic neurotransmission is an elemental "building block" of the oscillatory networks within the crustacean stomatogastric ganglion (STG). This study constitutes the initial characterization of glutamatergic currents in isolated STG neurons in primary culture. Superfusion of 1 mM L-glutamate evoked a current response in 45 of 65 neurons examined. The evoked current incorporated two kinetically distinct components in variable proportion: a fast desensitizing component and a slower component. The current was mediated by an outwardly rectifying conductance increase and reversed at -48.8 +/- 5.3 mV. Reducing the external chloride concentration by 50% deflected the glutamate equilibrium potential (Eglu) by +14 mV, while increasing external potassium threefold shifted Eglu by up to +6 mV. Ibotenic acid fully activated both components of the glutamate response. Saturating concentrations of glutamate completely occluded neuronal responses to ibotenic acid, indicating that ibotenic acid was activating the same receptor(s) as glutamate. Millimolar concentrations of quisqualic acid, kainate, AMPA, and NMDA each failed to evoke any response. Picrotoxin (10(-4)M) completely blocked the glutamate response. Niflumic acid (100 microM) blocked > 80% of the desensitizing component and congruent to 50% of the sustained component. Reduction or elimination of extracellular calcium did not abolish the response. This study extends the ionic and pharmacological analysis of glutamatergic conductances in STG neurons. The currents described are consistent with glutamatergic inhibitory synaptic and agonist-evoked responses previously described in situ. We discuss their pharmacology, ionic mechanisms, and functional significance. J Neurosci 19951510 6631-98938647132 1996 Oct,&Inhibitory glutamate receptor channels 97-136 8 2Inhibitory glutamate receptors (IGluRs) are a family of ion channel proteins closely related to ionotropic glycine and gamma-aminobutyric acid (GABA) receptors; They are gated directly by glutamate; the open channel is permeable to chloride and sometimes potassium. Physiologically and pharmacologically, IGluRs most closely resemble GABA receptors; they are picrotoxin-sensitive and sometimes crossdesensitized by GABA. However, the amino acid sequences of cloned IGluRs are most similar to those of glycine receptors. Ibotenic acid, a conformationally restricted glutamate analog closely related to muscimol, activates all IGluRs. Quisqualate is not an IGluR agonist except among pulmonate molluscs and for a unique multiagonist receptor in the crayfish Austropotamobius torrentium. Other excitatory amino acid agonists are generally ineffective. Avermectins have several effects on IGluRs, depending on concentration: potentiation, direct gating, and blockade, both reversible and irreversible. Since IGluRs have only been clearly described in protostomes and pseudocoelomates, these effects may mediate the powerful antihelminthic and insecticidal action of avermectins, while explaining their low toxicity to mammals. IGluRs mediate synaptic inhibition in neurons and are expressed extrajunctionally in striated muscles. The presence of IGluRs in a neuron or muscle is independent of the presence or absence of excitatory glutamate receptors or GABA receptors in the cell. Generally, extrajunctional IGluRs in muscle have a higher sensitivity to glutamate than do neuronal synaptic receptors. Some extrajunctional receptors are sensitive in the range of circulating plasma glutamate levels, suggesting a role for IGluRs in regulating muscle excitability The divergence of the IGlu/GABA/Gly/ACh receptor superfamily in protostomes could become a powerful model system for adaptive molecular evolution. Physiologically and pharmacologically, protostome receptors are considerably more diverse than their vertebrate counterparts. Antagonist profiles are only loosely correlated with agonist profiles (e.g., curare-sensitive GABA receptors, bicuculline-sensitive AChRs), and pharmacologically identical receptors may be either excitatory or inhibitory, and permeable to different ions. The assumption that agonist sensitivity reliably connotes discrete, homologous receptor families is contraindicated. Protostome ionotropic receptors are highly diverse and straightforward to assay; they provide an excellent system in which to study and integrate fundamental questions in molecular evolution and adaptation.'>8Biology Department 0357, UCSD, La Jolla 92093-0357, USA.Cleland, T. A.@:97093085 0893-7648 Journal Article Review Review, Academic Mol NeurobiolAmino Acid Sequence Animal Chloride Channels/drug effects/*physiology Chlorides/metabolism Evolution, Molecular Excitatory Amino Acid Agonists/pharmacology Excitatory Amino Acid Antagonists/pharmacology Gene Expression Glutamic Acid/*physiology Human Invertebrates/physiology Ion Channel Gating/physiology Molecular Sequence Data Nerve Tissue Proteins/physiology Neurons/physiology Neurotoxins/pharmacology Phylogeny Potassium/metabolism Potassium Channels/drug effects/*physiology Receptors, Glutamate/classification/drug effects/*physiology Sequence Alignment Sequence Homology, Amino Acid Support, U.S. Gov't, P.H.S. Vertebrates/physiologyjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=893864798070674& Cleland, T. A. Selverston, A. I.f`Dopaminergic modulation of inhibitory glutamate receptors in the lobster stomatogastric ganglionAnimal Dopamine/physiology Ganglia, Invertebrate/cytology/physiology Lobsters/*physiology Neural Inhibition/physiology Neurons/physiology Patch-Clamp Techniques Receptors, Glutamate/physiology Stomach/innervation Support, U.S. Gov't, P.H.S.The intrinsic rhythmicity of the spiny lobster stomatogastric ganglion (STG) is strongly influenced by the strengths of the graded synapses between identified cells within the neural network. These synaptic strengths can be powerfully influenced by chemical neuromodulators such as dopamine and serotonin. Most of the intraganglionic chemical synapses in the STG are mediated by postsynaptic inhibitory glutamate receptors (IGluRs). To determine whether or not direct effects on these IGluRs contribute to the modulation of synaptic strength, unidentified STG neurons were extracted into primary culture and the effects of these aminergic neuromodulators on the glutamate-evoked membrane current were assessed. Dopamine (100 microM) reliably and significantly reduced the whole cell slope conductance of all IGluRs tested. Serotonin (20 microM) never affected the IGlu response, although it clearly altered other cellular membrane properties. Although all identified STG neurons may not conform to these observations, the data reveal a specific dopamine-activated modulatory pathway within cultured neurons that reduces IGluR slope conductance. The relationship between IGluR modulation and net synaptic modulation in situ contributes to an emerging model in which synaptic strengths can be multiply modulated at different functional sites, yielding a complex, distributed, and state- dependent regulatory structure.J Neurophysiol 1997786e 3450-2\.^[ lfhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/18/7/278898171581F?Clemens, S. Massabuau, J. C. Legeay, A. Meyrand, P. Simmers, J.hIn vivo modulation of interacting central pattern generators in lobster stomatogastric ganglion: influence of feeding and partial pressure of oxygen Animal Anoxia/physiopathology Behavior, Animal/physiology Electrophysiology Feeding Behavior/drug effects/*physiology Ganglia, Invertebrate/drug effects/physiology Lobsters/*physiology Oxygen/*pharmacology Periodicity Stomach/innervation Support, Non-U.S. Gov'tif_The stomatogastric ganglion (STG) of the European lobster Homarus gammarus contains two rhythm-generating networks (the gastric and pyloric circuits) that in resting, unfed animals produce two distinct, yet strongly interacting, motor patterns. By using simultaneous EMG recordings from the gastric and pyloric muscles in vivo, we found that after feeding, the gastropyloric interaction disappears as the two networks express accelerated motor rhythms. The return to control levels of network activity occurs progressively over the following 1-2 d and is associated with a gradual reappearance of the gastropyloric interaction. In parallel with this change in network activity is an alteration of oxygen levels in the blood. In resting, unfed animals, arterial partial pressure of oxygen (PO2) is most often between 1 and 2 kPa and then doubles within 1 hr after feeding, before returning to control values some 24 hr later. In vivo, experimental prevention of the arterial PO2 increase after feeding leads to a slowing of pyloric rhythmicity toward control values and a reappearance of the gastropyloric interaction, without apparent effect on gastric network operation. Using in vitro preparations of the stomatogastric nervous system and by changing oxygen levels uniquely at the level of the STG within the range observed in the intact animal, we were able to mimic most of the effects observed in vivo. Our data indicate that the gastropyloric interaction appears only during a "free run" mode of foregut activity and that the coordinated operation of multiple neural networks may be modulated by local changes in oxygenation. J Neurosci 19981872788-99XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9779921*#Clemens, S. Meyrand, P. Simmers, J.,lfFeeding-induced changes in temporal patterning of muscle activity in the lobster stomatogastric systemAnimal Electromyography Feeding Behavior/*physiology Ganglia, Invertebrate/cytology/physiology Lobsters/*physiology Mastication/*physiology Muscles/*physiology Nerve Net/physiology Neurons/physiology Periodicity Support, Non-U.S. Gov't Time FactorsTMIn the lobster Homarus gammarus, rhythmic masticatory movements of the foregut gastric mill are generated by a small neural network in the stomatogastric ganglion. We have used EMG recordings from intact animals to analyse gastric network output in relation to cycle period before and after feeding. In pre-prandial conditions, muscles controlling lateral teeth closure and medial tooth protraction (driven by MG and GM motor neurons, respectively) express relatively constant, return stroke-like burst durations, but change to a variable-duration power stroke-like phenotype after feeding. In contrast, the LPG neuron- innervated lateral teeth opener muscle switches from power stroke to return stroke-like behavior. Thus alternate phases within a single motor program may invert their temporal properties according to the behavioral situation.'leLaboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and CNRS, UMR 5816, Arcachon, France.9779921 Neurosci Lett 1998 2542 65-8.:4Clemens, S. Massabuau, J. C. Meyrand, P. Simmers, J.vpChanges in motor network expression related to moulting behaviour in lobster: role of moult-induced deep hypoxiaThe well known rhythmically active pyloric neural network in intact and freely behaving lobsters Homarus gammarus was monitored prior to and following ecdysis. Despite long-lasting hormonal and metabolic alterations associated with this process, spontaneous pyloric network activity remained largely unaltered until the last 12-48 h before exuviation. At this time, the most notable change was a progressive lengthening of pyloric cycle period, which eventually attained 500-600 % of control values. It was only in the very last minutes before ecdysis that burst patterning became irregular and the otherwise strictly alternating motor sequence broke down. After the moult, coordinated rhythmicity was re-established within 10 min. Concomitant with these final changes in motor network expression at ecdysis was a drastic reduction in blood oxygen levels which led to a temporary near- anoxia. By imposing similarly deep hypoxic conditions both on intermoult animals and on the pyloric network in vitro, we mimicked to a large extent the moult-induced changes in pyloric network performance. Our data suggest that, despite major surrounding physiological perturbations, the pyloric network in vivo retains stable pattern-generating properties throughout much of the moulting process. Moreover, some of the most significant modifications in motor expression just prior to ecdysis can be related to a substantial reduction in oxygen levels in the blood.o'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and CNRS, UMR 5816, Avenue des Facultes, France and Laboratoire d'Ecophysiologie et Ecotoxicologie des Systemes Aquatiques, Universite Bordeaux I and CNRS, UMR 5805, Pla. 0010069971 J Exp Biol 1999 202e Pt 7817-27.shttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=0010069971 http://www.biologists.com/JEB/202/07/jeb1703.htmlec_N]ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=117187606:4Clemens, S. Massabuau, J. C. Meyrand, P. Simmers, J.b[A modulatory role for oxygen in shaping rhythmic motor output patterns of neuronal networksaAnimal Anoxia/physiopathology Feeding Behavior/physiology Ganglia, Invertebrate/cytology/physiology Lobsters Molting/physiology Motor Neurons/*physiology Neural Pathways/*physiology Oxygen/*pharmacokinetics Periodicity Support, Non-U.S. Gov't82It is becoming increasingly evident that O(2)-uptake in animal tissue is not only devoted to energy production. Here we review recent findings on a novel role of tissue oxygenation, notably in controlling the operation of neuronal networks in the central nervous system. Electrophysiological recordings in vivo and in vitro from rhythmically- active motor pattern generating networks in the lobster stomatogastric ganglion (STG) have revealed that oxygen is able to act in a manner equivalent to a classical neuromodulator. Local P(O(2)) variations within the low, but physiological range of 1-6 kPa are able to shape ongoing activity of these networks and therefore the motor behaviours in which they are involved. Oxygen's contribution to two of these, feeding and moulting, have been investigated. Importantly, the P(O(2)) effects are not related to hypoxic depression but are highly specific in terms of the network, neuron and even the synapse targeted. Our results are discussed in terms of functional significance and new research directions for mammalian physiology.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux 1 & CNRS, Unite Mixte de Recherche 5816, Avenue des Facultes, 33405, Talence, France.o11718760Respir Physiol 2001 128o3c299-315.XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=2366869Cohen, L. Wu, J. Y.eOne neuron, many units?dxrAnimal Cerebellum/cytology Guinea Pigs In Vitro Neurons/*physiology Purkinje Cells/*physiology Synapses/physiology2366869M Nature 1990 346  6280 108-9.93107364@:Coleman, M. J. Nusbaum, M. P. Cournil, I. Claiborne, B. J.d]Distribution of modulatory inputs to the stomatogastric ganglion of the crab, Cancer borealisNRLAnimal Crabs/*physiology Fluorescent Antibody Technique Ganglia/*cytology/physiology Histocytochemistry Lysine/analogs & derivatives Microscopy, Electron Neuropeptides/immunology/metabolism/physiology Neurotransmitters/immunology/metabolism Oligopeptides/immunology/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.The pyloric and gastric mill neural networks in the crustacean stomatogastric ganglion receive modulatory inputs from more anteriorly located ganglia via the stomatogastric nerve. In this study we employed biocytin backfilling and immunostaining, as well as electron microscopy, to determine the origin of these inputs in the crab, Cancer borealis. Fiber counts from electron micrographs of sections through the stomatogastric nerve showed that this nerve contains 55-60 medium to large diameter fibers (1-13 microns). These fibers were individually wrapped by several layers of membrane, presumably glial in origin. There was also a single cluster of jointly wrapped, small diameter ( 1 micron) fibers that may originate from peripheral sensory somata. Biocytin backfills revealed that approximately two thirds of the individually wrapped fibers in this nerve originate from somata in the other three ganglia of the stomatogastric nervous system, including the paired commissural ganglia and the single oesophageal ganglion. There were approximately 20 biocytin-labeled somata in each commissural ganglion and 3 somata in the oesophageal ganglion. An additional ten somata were localized to the stomatogastric ganglion itself. This accounts for nearly all of the medium to large diameter fibers in the stomatogastric nerve. We used double-labeling with backfills and immunocytochemistry to determine that there are two proctolin- immunoreactive neurons and four FMRFamide-like immunoreactive neurons among the biocytin-labeled neurons in each commissural ganglion. Both peptides modulate neural network activity in the stomatogastric ganglion.(ABSTRACT TRUNCATED AT 250 WORDS)t J Comp Neurolt 1992 325(4  581-94l rnntials*#Cournil, I. Meyrand, P. Moulins, M. 1990("Lobster stomatogastric GABA system @:Wiese, K. Krenz, W.-D. Tautz, J. Reichert, H. Mulloney, B.*$Frontiers in Crustacean Neurobiology Basel Birkhauser Verlag448-4547914897 3443 1994 Jun 15Dopamine in the lobster Homarus gammarus. I. Comparative analysis of dopamine and tyrosine hydroxylase immunoreactivities in the nervous system of the juveniley 455-69As a catecholamine, dopamine belongs to a class of molecules that have multiple transmitter and hormonal functions in vertebrate and invertebrate nervous systems. However, in the lobster, where many central neurons have been identified and the peripheral innervation pattern is well known, the distribution of dopamine-containing neurons has not been examined in detail. Therefore, immunocytochemical methods were used to identify neurons likely to contain dopamine and tyrosine hydroxylase in the central nervous system of the juvenile lobster Homarus gammarus. Approximately 100 neuronal somata stain for the catecholamine and/or its synthetic enzyme in the brain and ventral nerve cord. The systems of neurons labeled with dopamine and tyrosine hydroxylase antibodies have the following characteristics: 1) the two systems are nearly identical; 2) every segmental ganglion contains at least one pair of labeled neurons; 3) the positions and numbers of cell bodies labeled with each antiserum are similar in the various segmental ganglia; 4) six labeled neurons are anatomically identified; two interneurons from the brain project within the ventral cord to reach the last abdominal ganglion, two neurons from the commissural ganglia are presumably neurosecretory neurons, and two anterior unpaired medial abdominal neurons project to the hindgut muscles; and 5) no cell bodies are labeled in the stomatogastric ganglion, but fibers and terminals in the neuropil are stained. The remarkably small numbers of labeled neurons and the presence of very large labeled somata with far-reaching projections are distinctive features consistent with other modulatory aminergic systems in both vertebrates and invertebrates.'pjLaboratoire de Neurobiologie et Physiologie Comparees, CNRS et Universite de Bordeaux I, Arcachon, France.,&Cournil, I. Helluy, S. M. Beltz, B. S.("94342534 0021-9967 Journal Article J Comp NeurolAnimal Antibody Specificity Comparative Study Dopamine/immunology/*metabolism Ganglia, Invertebrate/enzymology/immunology/metabolism Immunohistochemistry Muscles/innervation Nephropidae/*metabolism Nervous System/enzymology/*metabolism Neural Pathways/cytology/immunology/metabolism Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tyrosine 3-Monooxygenase/immunology/*metabolismjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7914897e <d g 697215282("Combes, D. Simmers, J. Moulins, M.LFConditional dendritic oscillators in a lobster mechanoreceptor neuronezAnimal Dendrites/*physiology Lobsters Mechanoreceptors/*physiology Membrane Potentials/*physiology Support, Non-U.S. Gov't 1. Intra- and extracellular recordings were made from in vitro preparations of the lobster (Homarus gammarus) stomatogastric nervous system to study the nature and origin of pacemaker-like activity in a primary mechanoreceptor neurone, the anterior gastric receptor (AGR), whose two bilateral stretch-sensitive dendrites ramify in the tendon of powerstroke muscle GM1 of the gastric mill system. 2. Although the AGR is known to be autoactive, we report here that in 20% of our preparations, rather than autogenic tonic discharge, the receptor fired spontaneously in discrete bursts comprising three to ten action potentials and repeating at cycle frequencies of 0.5-2.5 Hz in the absence of mechanical stimulation. Intrasomatic recordings revealed that such rhythmic bursting was driven by slow oscillations in membrane potential, the frequency of which was voltage sensitive and dependent upon the level of stretch applied to the receptor terminals of the AGR. 3. Autoactive bursting of the AGR originated from an endogenous oscillatory mechanism in the sensory dendrites themselves, since (i) during both steady, repetitive firing and bursting, somatic and axonal impulses were always preceded 1:1 by dendritic action potentials, (ii) hyperpolarizing the AGR cell body to block triggering of axonal impulses revealed attenuated somatic spikes that continued to originate from the two peripheral dendrites, (iii) the timing of burst firing could be phase reset by brief electrical stimulation of either dendrite, and (iv) spontaneous bursting continued to be expressed by an AGR dendrite after physical isolation from the GM1 muscle and the stomatogastric nervous system. 4. Although a given AGR in vitro could switch spontaneously from dendritic bursting to tonic firing and vice versa, exogenous application of micromolar (or less) concentrations of the neuropeptide F1 (TNRNFLRFamide) to the dendritic membrane could rapidly and reversibly switch the receptor firing pattern from repetitive firing to the bursting mode. Exposure of the somatic and axonal membrane of the AGR to F1 was without effect, as were applications of other neuroactive substances such as serotonin, octopamine and proctolin. 5. We conclude that, as for many oscillatory neurones of the central nervous system, the intrinsic activity pattern of this peripheral sensory neurone may be dynamically conferred by extrinsic modulatory influences, presumably according to computational demands. Moreover, the ability of the AGR to behave as an endogenous burster imparts considerable integrative complexity since, in this activity mode, sensory coding not only occurs through the frequency modulation of on-going dendritic bursts but also via changes in the duration of individual bursts and their inherent spike frequencies.J Physiol (Lond) 1997 499 Pt 1 161-77("Combes, D. Meyrand, P. Simmers, J.f_Dynamic restructuring of a rhythmic motor program by a single mechanoreceptor neuron in lobster*#Animal Digestive System/innervation Ganglia, Invertebrate/*physiology In Vitro Lobsters Mechanoreceptors/*physiology Models, Neurological Motor Activity/*physiology Motor Neurons/physiology Muscle, Skeletal/innervation Neurons/*physiology Neurons, Afferent/physiology Support, Non-U.S. Gov'tF?We have explored the synaptic and cellular mechanisms by which a single primary mechanosensory neuron, the anterior gastric receptor (AGR), reconfigures motor output of the gastric mill central pattern generator (CPG) in the stomatogastric nervous system (STNS) of the lobster Homarus gammarus. AGR is activated in vivo by contraction of the medial tooth protractor muscle gm1 and accesses the gastric CPG via excitation of two in-parallel interneurons, the excitatory commissural gastric (CG) and the inhibitory gastric inhibitor (GI). In the spontaneously active STNS in vitro, weak firing of AGR in time with gastric mill motoneurons (GM) reinforces an ongoing type I gastric mill rhythm in which all gastric teeth power-stroke motoneurons are synchronously active. With strong AGR firing, these phase relationships switch abruptly to a type II pattern in which lateral and medial teeth power- stroke motoneurons fire in antiphase. Our results suggest that these bimodal actions on the gastric mill rhythm depend on the balance of firing of the CG and GI interneurons and that selection of the pathway resides in their different postsynaptic sensitivities to AGR. Whereas high intrinsic firing rates of the CG neuron ensure that the excitatory pathway predominates during low levels of sensory input, strong synaptic facilitation in the GI neuron favors the inhibitory pathway during high levels of receptor activity. Feedback from a single mechanosensory neuron is thus able, in an activity-dependent manner, to specify different motor programs from a single central pattern- generating network.a'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and Centre National de la Recherche Scientifique, Unite Mixte de Recherche 5816, 33405 Talence, France.h10212320http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10212320 http://www.jneurosci.org/cgi/content/full/19/9/3620l J Neurosci 1999199a3620-8.a("Combes, D. Meyrand, P. Simmers, J.d^Motor pattern specification by dual descending pathways to a lobster rhythm-generating network<5Animal Efferent Pathways/physiology Electric Stimulation Electromyography Evoked Potentials Ganglia, Invertebrate/*physiology In Vitro Interneurons/physiology Lobsters Mastication/*physiology Motor Activity/*physiology Motor Neurons/physiology Nerve Net/*physiology Neurons/*physiology Support, Non-U.S. Gov'tIn the European lobster Homarus gammarus, rhythmic masticatory movements of the three foregut gastric mill teeth are generated by antagonistic sets of striated muscles that are driven by a neural network in the stomatogastric ganglion. In vitro, this circuit can spontaneously generate a single (type I) motor program, unlike in vivo in which gastric mill patterns with different phase relationships are found. By using paired intrasomatic recordings, all elements of the gastric mill network, which consists mainly of motoneurons, have been identified and their synaptic relationships established. The gastric mill circuit of Homarus is similar to that of other decapod crustaceans, although some differences in neuron number and synaptic connectivity were found. Moreover, specific members of the lobster network receive input from two identified interneurons, one excitatory and one inhibitory, that project from each rostral commissural ganglion. Integration of input from these projection elements is mediated by synaptic interactions within the gastric mill network itself. In arrhythmic preparations, direct phasic stimulation of the previously identified commissural gastric (CG) interneuron evokes gastric mill output similar to the type I pattern spontaneously expressed in vitro and in vivo. The newly identified gastric inhibitor interneuron makes inhibitory synapses onto a different subset of gastric mill neurons and, when activated with the CG neuron, drives gastric mill output similar to the type II pattern that is only observed in the intact animal. Thus, two distinct phenotypes of gastric mill network activity can be specified by the concerted actions of parallel input pathways and synaptic connectivity within a target central pattern generator.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and Centre National de la Recherche Scientifique, Unite Mixte de Recherche 5816, 33405 Talence, France.10212319http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10212319 http://www.jneurosci.org/cgi/content/full/19/9/3610 J Neurosci 19991993610-9.8!JTuw>f "h 932536546/Combes, D. Simmers, J. Nonnotte, L. Moulins, M.rpjTetrodotoxin-sensitive dendritic spiking and control of axonal firing in a lobster mechanoreceptor neuroneAction Potentials/drug effects/physiology Animal Axons/*physiology Dendrites/*physiology Lobsters Mechanoreceptors/*physiology Support, Non-U.S. Gov't Tetrodotoxin/*pharmacology 1. A primary mechanosensory neurone, the anterior gastric receptor (AGR) associated with gastric mill muscle in the lobster foregut was examined in vitro with extra- and intra-cellular recording techniques to understand processes of dendritic integration and dendro-axonal communication. 2. AGR has a 'T'-shaped geometry; its two long (> 3 mm) primary dendrites project distally to spatially separate, stretch sensitive terminals and converge centrally onto a common apical neurite that leads to a bipolar soma and single axon. 3. The receptor's bilateral dendrites are independently capable of generating action potentials. These appear to be Na+ dependent since they are blocked by tetrodotoxin, but not by Co2+ or a lack of Ca2+ in the bath saline. 4. Both dendrites are autogenically active, although impulses in the dendrite with the higher intrinsic excitability may cross over and activate the trigger zone on the contralateral side. Moreover, spikes arising on either dendrite do not actively invade the soma, but are conveyed as decremented potentials to a third trigger zone on the initial axon segment. 5. Focal applications of TTX (tetrodotoxin) demonstrated the existence and allowed precise definition of a central membrane compartment of AGR that appears to lack in functional Na+ channels. This inexcitable region includes the soma, the apical neurite and the central branch point of the two dendrites. A failure to observe collision block of bilateral dendritic potentials as they traverse the neurite supported this conclusion. 6. Horseradish peroxidase injections and staining revealed two morphological features of the apical neurite that differed markedly from other regions of the cell. In addition to a relatively large diameter, the neurite's plasma membrane is heavily convoluted and coiled to form a lamellar transverse profile. This latter feature may itself contribute to membrane inexcitability while the former is consistent with an elevated space constant for electrotonic conduction. 7. It is concluded that the inhomogeneous distribution of membrane excitability in AGR enhances the integrative capability of the receptor's dendrites, permitting mechanical input at diverse loci to be encoded and processed prior to transformation into axonal discharge.J Physiol (Lond) 1993 460581-60296167628("Combes, D. Simmers, J. Moulins, M.\VStructural and functional characterization of a muscle tendon proprioceptor in lobster Animal Biomechanics Dendrites/ultrastructure Gastrointestinal Motility/*physiology Lobsters/*anatomy & histology/physiology Neurons, Afferent/physiology/*ultrastructure Proprioception/*physiology Support, Non-U.S. Gov't Tendons/*anatomy & histology/physiologyiHBA morphological and electrophysiological study was made on a unique primary mechanosensory neuron, the anterior gastric receptor (AGR), previously shown to arise from power-stroke muscle gm1 of the gastric mill system in the lobster foregut. Ultrastructural analysis of horseradish peroxidase injected AGR demonstrated that its peripheral dendrites do not ramify in muscle but are confined strictly to the connective tissue/epidermal interface in the tendon of gm1. These terminals are rich in mitochondria and at their very endings are free of glial cell wrapping, suggesting that they are the site at which mechano-transduction occurs. Extracellular axonal recordings from an in vitro neuromuscular preparation consisting of the gm1 muscle still attached to the stomatogastric nervous system, revealed that AGR is activated by passive stretch of gm1. The response to ramp stimuli displays dynamic and static components, both of which increase with the amplitude of applied stretch, while the dynamic component is also velocity sensitive. AGR is also activated by muscle contraction here elicited either by application of exogenous acetylcholine, the excitatory neurotransmitter for gm1, or by electrical stimulation of the motoneurons (GM) themselves. Consistent with a receptor lying in- series with its muscle, therefore, the effective stimulus of AGR in vivo is probably an increase in tension exerted on the tendon during active muscle contraction. In neuromuscular preparations including the bilateral commissural ganglia, stretching gm1 reflexly activates GM motoneurons at low stimulus strengths but leads to an inactivation of GM motoneurons at high stimulus strengths. This is consistent with earlier findings that both responses can be elicited by direct electrical stimulation of AGR. The functional implications of AGR's anatomical relationship with muscle gm1, the receptor's response properties, and its central effects on motor output to gm1 are discussed. Comparison is also drawn between this first reported example of a true tendon receptor in invertebrates and muscle receptors of vertebrates. J Comp Neurol 1995 3632 221-34 , $~,(Biogenic Amines/pharmacology/*physiology,'Biogenic Amines/pharmacology/physiology$Biogenic Monoamines/*physiologyBiological Clocks Biological Clocks/*physiology0*Biological Clocks/drug effects/*physiology Biological Clocks/physiologyBiological Transport Biomechanics Biotin/analogs & derivatives BistabilityBistable elementBlood Glucose/*physiologyBlood PhysiologyBlood Vessels/physiologyBlood/physiologyBlotting, Western Brachyura,)Brachyura/*anatomy & histology/physiologyBrain Chemistry Brain Chemistry/*physiologyBrain/*physiology Brain/cytology/*physiologyBrain/cytology/physiology Brain/embryology/*physiologyBrain/physiologyBromodeoxyuridine Bungarotoxins/pharmacology Bursting@=Ca(2+)-Calmodulin Dependent Protein Kinase/*analysis/geneticsCadmium/metabolismCaffeine/*pharmacologyCalcitonin/*analysis@;Calcitonin/administration & dosage/*pharmacology/physiology,&Calcium Channel Blockers/*pharmacology(%Calcium Channel Blockers/pharmacology0-Calcium Channels, L-Type/genetics/*metabolism0,Calcium Channels, P-Type/genetics/metabolism$Calcium Channels/*drug effects Calcium Channels/*physiology Calcium Channels/drug effects,)Calcium Channels/drug effects/*physiology,(Calcium Channels/drug effects/physiology Calcium Channels/metabolism Calcium Channels/physiology Calcium Signaling/physiology0-Calcium-Binding Proteins/genetics/*metabolismCalcium/*metabolism$ Calcium/*metabolism/pharmacologyCalcium/*physiologyCalcium/metabolism$Calcium/metabolism/*physiologyCalcium/pharmacologyCalcium/physiology(#Calmodulin/antagonists & inhibitors("Carbachol/antagonists & inhibitorsCarbon Isotopes$Cations, Divalent/pharmacologyCatsCell CommunicationCell Compartmentation Cell Count$Cell Differentiation/physiology Cell LineCell Membrane/*physiologyCell Membrane/enzymologyCell Membrane/metabolismCell Membrane/physiology,'Cell Membrane/physiology/ultrastructureCell Separation Cell Survival Cell Survival/drug effectsCells, Cultured("Central nervous system Congresses.("Central Nervous System/*physiology0+Central Nervous System/cytology/*physiologyHCCentral Nervous System/drug effects/enzymology/growth & development0,Central Nervous System/immunology/physiologyCerebellum/cytology$Cerebral Ventricles/physiologyCesium/pharmacology Chelating Agents/metabolism Chemistry0*Chloride Channels/drug effects/*physiologyChlorides/*metabolismChlorides/metabolismChlorides/pharmacologyChlorides/physiology Chlorisondamine/*pharmacology Chlorisondamine/*physiology,)Cholecystokinin/*isolation & purificationCholecystokinin/analysis@=Cholecystokinin/analysis/antagonists & inhibitors/isolation &DACholecystokinin/antagonists & inhibitors/pharmacology/*physiology,&Cholecystokinin/immunology/*metabolism,&Cholecystokinin/metabolism/*physiology CholineCholine/*metabolismCholine/metabolism0+Cholinergic Fibers/drug effects/*physiology,&Cholinesterase Inhibitors/pharmacology($Chromatography, High Pressure LiquidCircadian Rhythm Circadian Rhythm/*physiology Circadian Rhythm/drug effectsCitrulline/metabolismCloning, MolecularCockroaches/chemistryCockroaches/drug effectsComparative Study Computational Biology/methodsComputer SimulationComputer Systems Computers Conserved Sequence/physiologycrabCrabsCrabs/*analysis Crabs/*anatomy & histology(%Crabs/*anatomy & histology/physiology$Crabs/*drug effects/*physiologyCrabs/*metabolismCrabs/*physiologyCrabs/*ultrastructure(%Crabs/anatomy & histology/*physiology($Crabs/anatomy & histology/metabolismmki Meyrand, P.Coombs, E.G. Allen, J.A. 1978eThe functional morphology of the feeding appendages and gut of Hippolyte varians (Crustacea: Natania)A?PZool J Linn Soc Lond64261-282850242326/Cournil, I. Geffard, M. Moulins, M. Le Moal, M.nb[Coexistence of dopamine and serotonin in an identified neuron of the lobster nervous systemcAnimal Dopamine/*analysis/metabolism Ganglia/*analysis/metabolism Histocytochemistry Immunochemistry Lobsters/*metabolism Radioimmunoassay Serotonin/*analysis/metabolism Support, Non-U.S. Gov'tHThe combination of several analytical methods, i.e. chemical analysis (high performance liquid chromatography), biochemical analysis (radioimmunoassay) and immunohistochemistry, has shown that a single neuron can contain two 'classical' neurotransmitters.m Brain Rese 1984 310u2o397-400 91056330*#Cournil, I. Meyrand, P. Moulins, M.ijcIdentification of all GABA-immunoreactive neurons projecting to the lobster stomatogastric ganglionm Animal Digestive System/chemistry/innervation Evoked Potentials/physiology Fluorescent Dyes Ganglia/chemistry/cytology GABA/*analysis Immunoenzyme Techniques Isoquinolines Lobsters/*analysis/cytology Microelectrodes Neural Pathways/chemistry Neurons/chemistry NickelThe stomatogastric ganglion of lobsters (Homarus or Jasus) contains a large number of gamma-aminobutyric acid-immunoreactive processes originating from ten fibres in the single input nerve, the stomatogastric nerve. The cell bodies and axonal pathways of these ten fibres have been identified using gamma-aminobutyric acid immunohistochemistry in combination with Lucifer Yellow staining (double labelling) and nickel chloride backfilling (selective gamma- aminobutyric acid immunoinhibition). It is shown that eight gamma- aminobutyric acid-immunoreactive neurons project to the stomatogastric ganglion: gamma-aminobutyric acid neurons 1 and 2, found posterior to the oesophageal ganglion, entering the stomatogastric nerve via the oesophageal nerve as well as sending an axonal branch into each superior oesophageal nerve; gamma-aminobutyric acid neurons 3 and 4, found anterior to the oesophageal ganglion, each sending an axonal branch into each inferior oesophageal nerve to reach the stomatogastric nerve via the commissural ganglion and the superior oesophageal nerve; and gamma-aminobutyric acid neurons 5 and 6, found in each commissural ganglion, projecting into the stomatogastric nerve via the inferior oesophageal nerve, the oesophageal ganglion and the oesophageal nerve. These gamma-aminobutyric acid-immunoreactive neurons were also characterized by electrophysiological methods coupled with Lucifer Yellow labelling, and their picrotoxin-sensitive effects on several stomatogastric ganglion neurons were demonstrated. The present results provide a firm basis for further studies concerning the physiological significance of one class of neurochemically-defined input neurons to stomatogastric ganglion networks. J Neurocytol 1990194 478-93 dl95123456VOHarris-Warrick, R. M. Coniglio, L. M. Barazangi, N. Guckenheimer, J. Gueron, S.tmDopamine modulation of transient potassium current evokes phase shifts in a central pattern generator networkiAnimal Cesium/pharmacology Dopamine/*pharmacology Electric Conductivity Ganglia, Invertebrate/physiology Gastrointestinal Motility/physiology Lobsters Models, Neurological Neurons/drug effects/physiology *Periodicity Potassium/*physiology Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology 4-Aminopyridine/pharmacologydBath application of dopamine modifies the rhythmic motor pattern generated by the 14 neuron pyloric network in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. Among other effects, dopamine excites many of the pyloric constrictor (PY) neurons to fire at high frequency and phase-advances the timing of their activity in the motor pattern. These responses arise in part from direct actions of dopamine to modulate the intrinsic electrophysiological properties of the PY cells, and can be studied in synaptically isolated neurons. The rate of rebound following a hyperpolarizing prestep and the spike frequency during a subsequent depolarization are both accelerated by dopamine. Based on theoretical simulations, Hartline (1979) suggested that the rate of postinhibitory rebound in stomatogastric neurons could vary with the amount of voltage- sensitive transient potassium current (IA). Consistent with this prediction, we found that dopamine evokes a net conductance decrease in synaptically isolated PY neurons. In voltage clamp, dopamine reduces IA, specifically by reducing the amplitude of the slowly inactivating component of the current and shifting its voltage activation curve in the depolarized direction. 4-Aminopyridine, a selective blocker of IA in stomatogastric neurons, mimics and occludes the effects of dopamine on isolated PY neurons. A conductance-based mathematical model of the PY neuron shows appropriate changes in activity upon quantitative modification of the IA parameters affected by dopamine. These results demonstrate that dopamine excites and phase-advances the PY neurons in the rhythmic pyloric motor pattern at least in part by reducing the transient K+ current, IA. J Neurosci 199515 1 Pt 1 342-58uy{Jzx 89257515"Dickinson, P. S. Marder, E. Peptidergic modulation of a multioscillator system in the lobster. I. Activation of the cardiac sac motor pattern by the neuropeptides proctolin and red pigment-concentrating hormone.(Action Potentials Animal Female Heart/drug effects/*physiology Immunohistochemistry Lobsters/*physiology Male Motor Neurons/drug effects/physiology Neural Pathways Oligopeptides/*pharmacology Peptides/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.zs1. The cardiac sac motor pattern consists of slow and irregular impulse bursts in the motor neurons [cardiac sac dilator 1 and 2 (CD1 and CD2)] that innervate the dilator muscles of the cardiac sac region of the crustacean foregut. 2. The effects of the peptides, proctolin and red pigment-concentrating hormone (RPCH), on the cardiac sac motor patterns produced by in vitro preparations of the combined stomatogastric nervous system [the stomatogastric ganglion (STG), the paired commissural ganglia (CGs), and the oesophageal ganglion (OG)] were studied. 3. Bath applications of either RPCH or proctolin activated the cardiac sac motor pattern when this motor pattern was not already active and increased the frequency of the cardiac sac motor pattern in slowly active preparations. 4. The somata of CD1 and CD2 are located in the esophageal and stomatogastric ganglia, respectively. Both neurons project to all four of the ganglia of the stomatogastric nervous system. RPCH elicited cardiac sac motor patterns when applied to any region of the stomatogastric nervous system, suggesting a distributed pattern generating network with multiple sites of modulation. 5. The anterior median (AM) neuron innervates the constrictor muscles of the cardiac sac. The AM usually functions as a part of the gastric mill pattern generator. However, when the cardiac sac is activated by RPCH applied to the stomatogastric ganglion, the AM neuron becomes active in antiphase with the cardiac sac dilator bursts. This converts the cardiac sac motor pattern from a one-phase rhythm to a two-phase rhythm. 6. These data show that a neuropeptide can cause a neuronal element to switch from being solely a component of one neuronal circuit to functioning in a second one as well. This example shows that peptidergic "reconfiguration" of neuronal networks can produce substantial changes in the behavior of associated neurons.J Neurophysiol 1989614 833-4490174301,&Dickinson, P. S. Mecsas, C. Marder, E.B;Neuropeptide fusion of two motor-pattern generator circuits2,Animal Ganglia/*physiology Invertebrate Hormones/*physiology Lobsters Membrane Potentials Models, Neurological Motor Neurons/*physiology Nervous System/physiology Nervous System Physiology Neuropeptides/*physiology Oligopeptides/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Animals make many different movements as circumstances dictate. These movements often involve the coordination of several neural networks, the output of which can be changed by modulatory substances. Here we report that the neuropeptide red pigment concentrating hormone modulates the interactions between two rhythmic pattern-generating networks in the lobster stomatogastric nervous system. Red pigment concentrating hormone markedly enhances the amplitude of synaptic interactions between elements of two pattern-generating networks--the cardiac sac and the gastric mill. Consequently, two networks operating under some circumstances virtually independently can be fused into one functional unit operating differently from either of the two original networks. These results show how a neuropeptide can alter the functional configuration of a neural network so that widely disparate outputs can be produced by the same neurons. Nature 1990 344 6262 155-8"Dickinson, P.S. Moulins, M. 1992d^Interactions and combinations between different networks in the stomatogastric nervous system. BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MA  MIT Press139-1609328667981Dickinson, P. S. Mecsas, C. Hetling, J. Terio, K.rnhThe neuropeptide red pigment concentrating hormone affects rhythmic pattern generation at multiple sitesngAnimal Central Nervous System/*physiology Female Ganglia/*physiology Gastrointestinal Motility/*physiology Invertebrate Hormones/*physiology Lobsters/*physiology Male Membrane Potentials/physiology Nerve Fibers/physiology Nerve Net/*physiology Neurons/physiology Oligopeptides/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Tissue Culture 1. The cardiac sac network, which controls the rhythmic contractions of the cardiac sac in the foregut of crustaceans, is distributed throughout the stomatogastric nervous system, including the oesophageal ganglion (OG), the commissural ganglia (CGs), and the stomatogastric ganglion (STG). A red pigment-concentrating hormone (RPCH)-like peptide is likewise widely distributed. 2. The effects that bath application of the neuropeptide RPCH to the different ganglia has on the cardiac sac pattern were studied. 3. RPCH applied to the STG, the OG, or the CGs elicited bursting activity in all the known components of the cardiac sac pattern, including the two motor neurons, cardiac sac dilators 1 and 2 (CD1 and CD2), and the inferior ventricular nerve (ivn) fibers. 4. A cardiac sac pattern was also elicited when RPCH was applied to either the STG, the OG, or the CGs after synapses in that ganglion had been blocked by low Ca2+ saline containing 20 mM Co2+. 5. These data suggest that the ivn fibers are sensitive to RPCH and respond to it by generating bursting activity at or near their terminals in all four ganglia. 6. Application of RPCH to either the STG or the OG also caused an increase in the amplitude of the postsynaptic potential (PSP) from the ivn fibers to both CD1 and CD2. The increase was largest in the ganglion to which the RPCH was applied. 7. Repeated stimulation of the ivn, mimicking the bursts that occur during cardiac sac activity, also caused an increase in PSP amplitude, and so facilitation resulting from activation of ivn bursting could account for a portion of the increased amplitude seen in RPCH.(ABSTRACT TRUNCATED AT 250 WORDS)J Neurophysiol 1993695i1475-83i\Vhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://biomednet.com/article/nb561496403286Dickinson, P. S.6/Interactions among neural networks for behavior}Animal Behavior/*physiology Behavior, Animal/*physiology Human Nerve Net/cytology/*physiology Neurons/physiology *Periodicityt(!In recent years, as our understanding of the pattern-generating networks responsible for a variety of behaviors has increased, the interactions of multiple neural networks have been examined in a number of systems. These studies have shown that functionally related pattern generators can interact extensively, and that the extent to which two or more of these networks interact is not fixed, but can be altered by neuromodulators. Furthermore, a number of studies have begun to elucidate the mechanisms responsible for those interactions. In the crustacean stomatogastric system, for example, neurons can switch between different pattern generators, and whole networks can fuse into single patterns. In addition, several networks can be dismantled, and their components used to generate a new network. The mechanisms responsible for these changes are the same as those involved in other circuit re-configurations, namely alterations of both intrinsic membrane properties of component neurons and alterations in the strength of synapses within the networks.uCurr Opin Neurobiol  19955e6i 792-8r B93057722$Elson, R. C. Selverston, A. I.Mechanisms of gastric rhythm generation in the isolated stomatogastric ganglion of spiny lobsters: bursting pacemaker potentials, synaptic interactions, and muscarinic modulationAnimal Electrophysiology Ganglia/*physiology In Vitro Lobsters/*physiology Muscarine/*metabolism Nerve Net/physiology Neural Inhibition Neural Pathways/physiology Neurons/physiology *Periodicity Stomach/*innervation/physiology Support, U.S. Gov't, P.H.S. Synapses/*physiologya 1. The gastric central pattern generator (CPG), located in the stomatogastric ganglion (STG) of the spiny lobster (Panulirus interruptus), is nonrhythmic when deprived of neuromodulatory inputs from anterior ganglia. Leaving these inputs intact in vitro can sustain a gastric rhythm but also introduces numerous, uncontrolled and largely unknown modulatory and synaptic influences that greatly complicate analysis of this CPG. 2. Here we induced gastric rhythms in the isolated STG, by superfusing a specific modulator, the muscarinic agonist, pilocarpine. Muscarinic agents sustain vigorous gastric rhythms in the isolated STG. Our aim was to analyze the pattern- generating functions of the restricted gastric circuit, free of complicating influences from other ganglia, and under specific (muscarinic) modulation. 3. We used combinations of multiple cell hyperpolarizations, photodeletions, and synaptic blockade by picrotoxin to assess the pattern-generating role of individual gastric neurons and to study the activity of subcircuits. 4. Four identified gastric neurons [lateral gastric (LG), dorsal gastric (DG), 2 electrically coupled lateral posterior gastric (2LPGs)] acted as pattern-generating cells. They showed bursting pacemaker potentials (BPPs), i.e., plateau (or driver) potentials that underlay bursts of axonal spikes and slow, interburst depolarizing potentials that underlay repetitive burst activity. LG and DG, at least, became conditional bursters, able to burst repetitively because of intrinsic oscillations. The other gastric neurons behaved mainly as follower cells and derived their rhythmic bursting from synaptic coupling to the pattern-generator cells and from their own intrinsic (but nonoscillatory) properties. 5. The pattern- generating neurons form a novel "kernel" circuit that works by the cooperative interaction of cellular properties and synaptic connectivity. 6. This study constitutes the first complete and fully consistent analysis of pattern generation in the gastric network of the isolated STG. These mechanisms pertain to muscarinic rhythms in particular but also, we suggest, to gastric rhythm generation and CPG function in general. We suggest that 1) rhythmicity normally depends on the induction of bursty membrane properties in at least some component neurons; 2) different subcircuits can produce rhythmic patterns and may be activated by different modulators; and 3) the gastric network shares several important "building blocks" with CPGs that have been analyzed in other systems. 7. Muscarinic inputs are implicated as an important gastric regulator. We compare these responses with the reported modulatory actions of the anterior pyloric modulator (AMP), an identified, putatively cholinergic input interneuron that may act via muscarinic mechanisms.J Neurophysiol 1992683890-907 t~| }rpsqoj96154815<5Cournil, I. Casasnovas, B. Helluy, S. M. Beltz, B. S.zsDopamine in the lobster Homarus gammarus: II. Dopamine-immunoreactive neurons and development of the nervous systemiAnimal Antibody Specificity Dopamine/*analysis/immunology Embryo, Nonmammalian/chemistry Eye/innervation/ultrastructure Female Ganglia, Invertebrate/chemistry Immunohistochemistry Larva/chemistry Lobsters/*chemistry/*physiology Muscles/innervation Nervous System/physiology Nervous System Physiology Neuronal Plasticity/physiology Neurons/*chemistry Neurotransmitters/*analysis/immunologyDopamine-immunoreactive neurons were revealed in lobster embryos, larvae, and postlarvae, and staining patterns were compared to neuronal labeling in the juvenile lobster nervous system (Cournil et al. [1994] J. Comp. Neurol. 344:455-469). Dopamine immunoreactivity is first detected by midembryonic life in 35-40 neuronal somata located anteriorly in brain and subesophageal ganglion. When the lobsters assume a benthic life during the first postlarval stage, an average of 58 cell bodies are labeled. The acquisition of dopamine in lobster neurons is a protracted event spanning embryonic, larval, and postlarval life and finally reaching the full complement of roughly 100 neurons in juvenile stages. Some of the dopaminergic neurons previously identified in the mature nervous system, such as the paired Br cells, L cells, and mandibular cells, are labeled in embryos and persist throughout development. In contrast, other neurons stain transiently for dopamine during the developmental period, but, by the adult stage, these neurons are no longer immunoreactive. Such transiently labeled neurons project to the foregut, the thoracic dorsal muscles, the neurohormonal pericardial plexus, and the pericardial pouches. It is proposed that these neurons are alive and functioning in adult lobster but that dopamine levels have been abolished, providing that neurotransmitter status is a dynamic, changing process. J Comp Neurol  1995 362u1e 1-16 Dall, W. Moriarty, D.J.W. 19834-Functional aspects of nutrition and digestion  Mantel, L.H.NGThe Biology of Crustacea: Internal Anatomy and Physiological Regulation New York Academic Press5215-26169137086"Dando, M. R. Laverack, M. S.b\The anatomy and physiology of the posterior stomach nerve (p.s.n.) in some decapod crustaceaAction Potentials Animal *Autonomic Nervous System/anatomy & histology/physiology *Crustacea Electric Stimulation Gastrointestinal System/*innervation Receptors, Sensory Reflex Proc R Soc Lond B Biol Sci 1969 171n25 465-82"Dando, M.R. Selverston, A.I. 1972dCommand fibres from the supra-oesophageal ganglion to the stomatogastric ganglion in Panulirus argusTJ Comp Physiol78138-175("Dando, M.R. Chanussot, B. Nagy, F. 1974Activation of command fibres to the stomatogastric ganglion by input form a gastric mill proprioceptor in the crab, Cancer pagurustMar Behav Physiol2197-228"Dando, M. R. Maynard, D. M.  1974NThe sensory innervation of the foregut of Panulirus argus (Decapoda Crustacea)*9Mar Behav Physiol2283-305f81241613,%Dickinson, P. S. Nagy, F. Moulins, M.4TMInterganglionic communication by spiking and nonspiking fibers in same neuronfAnimal Esophagus/innervation Female Ganglia/*physiology Lobsters/physiology Male Motor Neurons/physiology Nerve Fibers/*physiology Neurons/ultrastructure Support, Non-U.S. Gov't *Synaptic TransmissionJ Neurophysiol 1981456u1125-38S84009538 Dickinson, P. S. Nagy, F.aControl of a central pattern generator by an identified modulatory interneurone in crustacea. II. Induction and modification of plateau properties in pyloric neuronesAnimal Digestive System/*innervation Electric Conductivity Esophagus/innervation Female Interneurons/*physiology Lobsters Male Membrane Potentials Support, Non-U.S. Gov'tIn the isolated stomatogastric nervous system of the lobster Fasus lalandii, the strong modifications of the pyloric motor pattern induced by firing of the single anterior pyloric modulator neurone (APM) are due primarily to modulation by APM activity of the regenerative membrane properties which are responsible for the 'burstiness' of all the pyloric neurones and particularly of the non-pacemaker neurones (constrictor motoneurones). This modulation has been studied under experimental conditions where the main extrinsic influences usually received by the pyloric constrictor neurones (intra-network synaptic interactions, activity of pacemaker neurones, and phasic central inputs from two premotor centres) are minimal. Under these conditions a brief discharge of neurone APM induces long plateaus of firing in all of the pyloric neurones. The non-pacemaker neurones of the pyloric network are not simply passive follower neurones, but can produce regenerative depolarizations (plateau potentials) during which the neurones fire spikes. The ability of the pyloric constrictor neurones to produce plateau potentials (plateau properties) contributes greatly to the generation of the rhythmical pyloric motor pattern. When these neurones spontaneously express their plateau properties, firing of neurone APM amplifies these properties. When most of the central inputs usually received by the pyloric constrictor neurones are experimentally suppressed, these neurones can no longer produce plateau potentials. In such conditions, firing of the single modulatory neurone APM can reinduce plateau properties of the pyloric constrictor neurones. In addition, firing in APM neurone slows down the active repolarization phase which terminates the plateau potentials of pyloric constrictor neurones. This effect is long-lasting and voltage-dependent. Modulation by APM of the plateau properties of the pyloric neurones also changes the sensitivity of these neurones to synaptic inputs. This effect can explain the strong modifications that an APM discharge exerts on a current pyloric motor pattern. Moreover, it might render the motoneurones of the pyloric pattern generator more sensitive to inputs from a command oscillator, and contribute to switching on the pyloric motor pattern. J Exp Biol 1983 105 59-82*$Dickinson, P.S. Nagy, F. Moulins, M. 1988Control of central pattern generators by an identified neurone in crustacea: Activation of the gastric mill motor pattern by a neurone known to modulate the pyloric network J Exp Biol 136 53-87Dickinson, P.S. 1989rkMotor program selection in the arthropod stomatogastric nervous system: Motor output in a modulated network .(Erber, J Menzel, R. Pfluger, H. Todt, D.$Neural Mechanisms of Behavior  Stuttgart Georg Thieme Verlage184-1858 8wLv97218396D=Dickinson, P. S. Fairfield, W. P. Hetling, J. R. Hauptman, J.nNeurotransmitter interactions in the stomatogastric system of the spiny lobster: one peptide alters the response of a central pattern generator to a second peptide(Animal Dose-Response Relationship, Drug Female Gastrointestinal System/*drug effects/physiology Lobsters Male Neurotransmitters/*pharmacology Oligopeptides/*pharmacology Patch-Clamp Techniques Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.Two of the peptides found in the stomatogastric nervous system of the spiny lobster, Panulirus interruptus, interacted to modulate the activity of the cardiac sac motor pattern. In the isolated stomatogastric ganglion, red-pigment-concentrating hormone (RPCH), but not proctolin, activated the bursting activity in the inferior ventricular (IV) neurons that drives the cardiac sac pattern. The cardiac sac pattern normally ceased within 15 min after the end of RPCH superfusion. However, when proctolin was applied within a few minutes of that time, it was likewise able to induce cardiac sac activity. Similarly, proctolin applied together with subthreshold RPCH induced cardiac sac bursting. The amplitude of the excitatory postsynaptic potentials from the IV neurons to the cardiac sac dilator neuron CD2 (1 of the 2 major motor neurons in the cardiac sac system) was potentiated in the presence of both proctolin and RPCH. The potentiation in RPCH was much greater than in proctolin alone. However, the potentiation in proctolin after RPCH was equivalent to that recorded in RPCH alone. Although we do not yet understand the mechanisms for these interactions of the two modulators, this study provides an example of one factor that can determine the "state" of the system that is critical in determining the effect of a modulator that is "state dependent," and it provides evidence for yet another level of flexibility in the motor output of this system.J Neurophysiol 1997772e599-610p>7Dickinson, P. S. Hauptman, J. Hetling, J. Mahadevan, A.ihbRCPH modulation of a multi-oscillator network: effects on the pyloric network of the spiny lobsterrlAnimal Electrophysiology Female Heart/physiology Invertebrate Hormones/*pharmacology Lobsters/*physiology Male Nerve Net/*drug effects/*physiology Neural Inhibition/physiology Neurons/physiology Oligopeptides/*pharmacology Oscillometry Pylorus/*innervation Reference Values Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Synaptic Transmission/drug effectsThe neuropeptide red pigment concentrating hormone (RPCH), which we have previously shown to activate the cardiac sac motor pattern and lead to a conjoint gastric mill-cardiac sac pattern in the spiny lobster Panulirus, also activates and modulates the pyloric pattern. Like the activity of gastric mill neurons in RPCH, the pattern of activity in the pyloric neurons is considerably more complex than that seen in control saline. This reflects the influence of the cardiac sac motor pattern, and particularly the upstream inferior ventricular (IV) neurons, on many of the pyloric neurons. RPCH intensifies this interaction by increasing the strength of the synaptic connections between the IV neurons and their targets in the stomatogastric ganglion. At the same time, RPCH enhances postinhibitory rebound in the lateral pyloric (LP) neuron. Taken together, these factors largely explain the complex pyloric pattern recorded in RPCH in Panulirus.c'`YDepartment of Biology, Bowdoin College, Brunswick, Maine 04011, USA. pdickins@bowdoin.edun11287466J Neurophysiol 2001854 1424-35.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11287466 http://www.jn.physiology.org/cgi/content/full/85/4/1424 http://www.jn.physiology.org/cgi/content/abstract/85/4/1424m Dindle, H. Caldwell, R.L. 1978b\Ecology and morphology of feeding and agonistic behavior in mudflat stomatopods (Squillidae) Biol Bull 155134-149ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10477125 ZTDircksen, H. Skiebe, P. Abel, B. Agricola, H. Buchner, K. Muren, J. E. Nassel, D. R.Structure, distribution, and biological activity of novel members of the allatostatin family in the crayfish Orconectes limosushAmino Acid Sequence Animal Chromatography, High Pressure Liquid Cockroaches/drug effects Crayfish/*chemistry Immunoenzyme Techniques Immunohistochemistry Muscles/drug effects/physiology Neuropeptides/chemistry/*metabolism/pharmacology Support, Non-U.S. Gov't<6In the central and peripheral nervous system of the crayfish, Orconectes limosus, neuropeptides immunoreactive to an antiserum against allatostatin I (= Dipstatin 7) of the cockroach Diploptera punctata have been detected by immunocytochemistry and a sensitive enzyme immunoassay. Abundant immunoreactivity occurs throughout the central nervous system in distinct interneurons and neurosecretory cells. The latter have terminals in well-known neurohemal organs, such as the sinus gland, the pericardial organs, and the perineural sheath of the ventral nerve cord. Nervous tissue extracts were separated by reverse-phase high-performance liquid chromatography and fractions were monitored in the enzyme immunoassay. Three of several immunopositive fractions have been purified and identified by mass spectroscopy and microsequencing as AGPYAFGL-NH2, SAGPYAFGL-NH2, and PRVYGFGL-NH2. The first peptide is identical to carcinustatin 8 previously identified in the crab Carcinus maenas. The others are novel and are designated orcostatin I and orcostatin II, respectively. All three peptides exert dramatic inhibitory effects on contractions of the crayfish hindgut. Carcinustatin 8 also inhibits induced contractions of the cockroach hindgut. Furthermore, this peptide reduces the cycle frequency of the pyloric rhythms generated by the stomatogastric nervous system of two decapod species in vitro. These crayfish allatostatin-like peptides are the first native crustacean peptides with demonstrated inhibitory actions on hindgut muscles and the pyloric rhythm of the stomatogastric ganglion.'TNInstitute of Zoophysiology, University of Bonn, Germany. Dircksen@uni- bonn.de10477125 1999Peptides206695-712 Using Smart Source Parsing .*#Faumont, S. Simmers, J. Meyrand, P.MnhActivation of a lobster motor rhythm-generating network by disinhibition of permissive modulatory inputsAction Potentials/physiology Animal Ganglia, Invertebrate/cytology/*physiology In Vitro Lobsters Motor Neurons/*physiology Nerve Net/*physiology *Periodicity Support, Non-U.S. Gov'to.'Rhythm generation by the gastric motor network in the stomatogastric ganglion (STG) of the lobster Homarus gammarus is controlled by modulatory projection neurons from rostral commissural ganglia (CoGs); blocking action potential conduction in these inputs to the STG of a stomatogastric nervous system in vitro rapidly renders the gastric network silent. However, exposure of the CoGs to low Ca2+ saline to block chemical synapses activates a spontaneously silent gastric network or enhances an ongoing gastric rhythm. A similar permissive effect was observed when picrotoxin was also superfused on these ganglia. We conclude that in the CoGs continuous synaptic inhibition is exerted on modulatory projection neuron(s) and that release from this inhibition allows strong activation of the gastric network.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I et Centre National de la Recherche Scientifique Unite Mixte de Recherche 5816, F-33120 Arcachon, France.9819280http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9819280 http://jn.physiology.org/cgi/content/full/80/5/2776J Neurophysiol 19988052776-80.$Felgenhauer, B.E. Abele, L.G.  1985PIFeeding structures of 2 Atyid shrimps with comments on Caridean phylogeny J Crust Biol53397-419$Felgenhauer, B.E. Abele, L.G.  19894.Evolution of the foregut in the lower Decapoda @9Felgenhauer, B.E. Watling, L. Thistle, A.B. Balkema, A.A.TMCrustacean Issues: Functional Morphology of Feeding and Grooming in Crustacea  Rotterdam  Brookfield6205-219XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9733079<5Fenelon, V. S. Casasnovas, B. Faumont, S. Meyrand, P.e}Ontogenetic alteration in peptidergic expression within a stable neuronal population in lobster stomatogastric nervous systemnAnimal Antibodies Antimetabolites Bromodeoxyuridine Cell Count Ganglia, Invertebrate/chemistry/cytology/growth & development Larva/growth & development/metabolism Lobsters/*physiology Nervous System/cytology/growth & development/metabolism Neuronal Plasticity/physiology Neurons/chemistry/cytology/*metabolism Neurotransmitters/metabolism Oligopeptides/analysis/immunology/*metabolism Support, Non-U.S. Gov't("In the adult lobster, Homarus gammarus, the stomatogastric ganglion (STG) contains two well-defined motor pattern generating networks that receive numerous modulatory peptidergic inputs from anterior ganglia. We are studying the appearance of extrinsic peptidergic inputs to these networks during ontogenesis. Neuron counts indicate that as early as 20% of development (E20) the STG neuronal population is quantitatively established. By using immunocytochemical detection of 5-bromo-2'- deoxyuridine incorporation, we found no immunopositive cells in the STG by E70. We concluded that the STG neuronal population remains quantitatively stable from mid-embryonic life until adulthood. We then investigated the ontogeny of FLRFamide- and proctolin-like peptides in the stomatogastric nervous system, from their first appearance until adulthood by using whole mount immunocytochemistry. Numerous FLRFamide- like-immunoreactive STG neuropilar ramifications were observable as early as E45 and remain thereafter. From E50 to the first larval stage, one to three STG somata stained, while somatic staining was not observed in larval stage II and subsequent stages. From E50 and thereafter, the STG neuropilar area was immunopositive for proctolin. One to two proctolinergic somata were detected in the STG of the three larval stages but were not seen in embryos, the post-larval stage or in adults. Thus, peptidergic inputs to the STG are present from mid- embryonic life. Moreover, whereas in the adult, STG neurons only contain glutamate or acetylcholine, some neurons transiently express peptidergic phenotypes during development. Although this system expresses an ontogenetic peptidergic plasticity, the STG neurons produce a single stable embryonic-larval motor output (Casasnovas and Meyrand [1995] J. Neurosci. 15:5703-5718).'zLaboratoire de Neurobiologie des Reseaux, CNRS et Universite de Bordeaux I, Arcachon, France. v.fenelon@lnpc.u-bordeaux.fr9733079 J Comp Neurol 1998 3993289-305.99142388e6i 1998 Decs0*Development of rhythmic pattern generators 705-9g|uIn contrast to the wealth of knowledge about the organizational rules of adult central pattern generators, far less is known about how these networks are assembled during development. The basic architecture for adult central pattern generators appears early in development but different generators may follow completely different developmental pathways to reach maturity. Recent evidence suggests that neuromodulatory inputs, in addition to their short-term adaptive control of central pattern generator activity, play a crucial role in both the final developmental tuning and the long-term maintenance of adult network function.o'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and CNRS UMR 5816, Place du Dr Peyneau, F-33120 Arcachon, France.n<5Fenelon, V. S. Casasnovas, B. Simmers, J. Meyrand, P.o@:99116054 0959-4388 Journal Article Review Review, TutorialCurr Opin Neurobiol Aging/physiology Animal Brain/embryology/*physiology Embryo/physiology Motor Activity/physiology Neural Pathways/physiology *Periodicity Support, Non-U.S. Gov'tjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9914238 d 84188169& Edwards, D. H., Jr. Mulloney, B.f`Compartmental models of electrotonic structure and synaptic integration in an identified neuroneAction Potentials Animal *Cell Compartmentation Computers Dendrites/physiology Electric Conductivity Electric Stimulation Lobsters *Models, Neurological Motor Neurons/*physiology Neural Inhibition Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiologymA three-compartment model of the electrotonic structure of an identified motoneurone, the median gastric (m.g.) neurone of the stomatogastric ganglion of the spiny lobster (Panulirus interruptus) was constructed, based on the passive response of the cell to a step of injected current. While its structure is only remotely related to that of the cell, the model is able to predict the passive response of the cell to any wave form of injected current. The shape of the m.g. neurone provided the basis for the development of a multicompartment model of the cell from the simple compartment model. Unlike the three- compartment model, the multicompartment model has a structure that corresponds closely to that of the cell while it retains the ability to predict the passive response of the cell to any wave form of injected current. The multicompartment model was used to analyse the electrotonic structure and synaptic integration of the cell. The axon acts as a current sink, causing steady-state voltage attenuation between the tips of different dendrites and the integrating segment to range between 26 and 89%. Steady-state voltage attenuation in the distal direction is 2% or less. Synaptic inhibition of m.g. by Interneurone 1 was simulated with simultaneously activated conductance- increase synapses located on all dendritic end-compartments of the model. Inhibitory post-synaptic potential (i.p.s.p.) wave forms recorded in the cell soma were duplicated in the soma compartment when the synaptic conductance change in each of the twenty-eight end- compartments was set equal to 5 nS for 8 ms. I.p.s.p. wave forms in dendritic end-compartments were 30% larger than the soma compartment i.p.s.p., while i.p.s.p.s in the integrating segment compartment were intermediate in size. Charge from a 92 mV, 1 ms action potential in the model axon was passively conducted from axonal compartments to the soma compartment of the model, where it reproduced the attenuated, broadened voltage wave forms of action potentials recorded in the cell soma. Passive spread of charge from an axonal action potentials to terminal dendritic compartments evoked potentials there that were 30% larger and faster than the corresponding soma compartment potential.J Physiol (Lond) 1984 348 89-11383111097Eisen, J. S. Marder, E.bMechanisms underlying pattern generation in lobster stomatogastric ganglion as determined by selective inactivation of identified neurons. III. Synaptic connections of electrically coupled pyloric neuronsAnimal Electrophysiology Evoked Potentials Ganglia/*physiology Interneurons/physiology Light Lobsters/*physiology Motor Neurons/physiology Periodicity Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology Synaptic Transmissionxr1. The pyloric dilator (PD) and anterior burster (AB) neurons in the pyloric system of the lobster stomatogastric ganglion are electrically coupled and synchronously active. We have used the lucifer yellow photoinactivation technique to separate the connections made by the PD motor neurons from those made by the AB interneuron. 2. Photoinactivation of either the two PD neurons or the single AB neuron allowed us to separate the compound inhibitory postsynaptic potentials (IPSPs) in the lateral pyloric (LP) and pyloric (PY) motor neurons resulting from synchronous PD and AB activity into AB-evoked and PD- evoked components. These IPSPs have different time courses, reversal potentials, ion selectivities, and pharmacological properties. 3. Photoinactivation and membrane-potential manipulations indicated that a readily observable IPSP recorded in the AB neuron and correlated with action potentials in the LP neuron is actually an electrotonic potential due to an LP-evoked IPSP in the PD neurons. 4. Selective inactivation of either the two PD neurons or the AB neuron revealed that the IPSP recorded in the ventricular dilator (VD) motor neuron is due solely to AB-released transmitter. 5. The electrical coupling potentials measurable between the AB, PD, and VD neuron somata are due to direct electrical coupling between all of these neurons. 6. Circuit analysis and transmitter identification may be complicated by electrical coupling. We suggest that the presence of electrical coupling between nonidentical neurons may provide a new mechanism that allows changes in synaptic characteristics among neurons within a "hard- wired" circuit.J Neurophysiol 1982486 1392-141584241938Eisen, J. S. Marder, E. HAA mechanism for production of phase shifts in a pattern generatormAnimal Biomechanics Interneurons/physiology Lobsters Motor Neurons/physiology Neurons/physiology Neurotransmitters/physiology Pyloric Antrum/*innervation Reaction Time Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/physiologye During motor activity of the pyloric system of the lobster stomatogastric ganglion, there are rhythmic alternations between activity in the pyloric dilator (PD) and pyloric (PY) motor neurons. We studied the phase relations between PD motor neuron activity and PY motor neuron activity in preparations cycling at a wide range of frequencies and after altering the activity of the PD neurons. The PY neurons fall into two classes, early (PE) and late (PL) (21), distinguished by the different phases in the pyloric cycle at which they fire. The phase at which PE neurons fired and the phase at which PL neurons fired was independent of pyloric cycle frequency over a range of frequencies from 0.5 to 2.25 Hz. The anterior burster (AB) interneuron is electrically coupled to the PD motor neurons. Together the AB and PD neurons form the pacemaker for the pyloric system. Synchronous depolarization of the AB and PD neurons evokes a complex inhibitory post-synaptic potential (IPSP) in PY neurons. This IPSP has two components: an early, AB neuron-derived component and a late, PD neuron-derived component. Deletion of the PD neurons from the pyloric circuit by photoinactivation removed the PD-evoked component of the pacemaker-evoked IPSP. This resulted in a decrease in the duration of the IPSP evoked by pacemaker depolarization and a significant advance in the firing phase of PY neurons. Bath application of dopamine was used to hyperpolarize and inhibit the PD neurons (30), causing them to release less neurotransmitter. As a consequence, the duration of the IPSP evoked by pacemaker depolarization was decreased and the firing phase of the PY neurons was significantly advanced. Stimulation of the inferior ventricular nerve (IVN) produces a slow excitation of the PD neurons (30), causing them to release more neurotransmitter. Consequently, the duration of the IPSP evoked by pacemaker depolarization was increased and the firing phase of the PY neurons was significantly retarded for several cycles of pyloric activity following IVN stimulation. Thus, modulation of the strength of PD-evoked inhibition in PY neurons is responsible for altering the firing phase of the PY neurons with respect to the pyloric pacemaker. We suggest that frequency of the pyloric output and the phase relations of the elements within the pyloric cycle can be regulated independently. The potential implications of these data for modulation of synaptic efficacy in other preparations are discussed.J Neurophysiol 19845161375-93  96150913$Elson, R. C. Selverston, A. I.ztSlow and fast synaptic inhibition evoked by pattern-generating neurons of the gastric mill network in spiny lobstershaAction Potentials/physiology Animal Chlorides/pharmacology Evoked Potentials/drug effects/physiology Lobsters/*physiology Neural Inhibition/drug effects/*physiology Neurons/drug effects/*physiology Picrotoxin/pharmacology Potassium/pharmacology Pylorus/*innervation Support, U.S. Gov't, P.H.S. Synaptic Transmission/drug effects/*physiology Time Factorso Z T1. In this paper we begin an assessment of the role of synaptic properties, especially synaptic time course, in the function of the central pattern generator circuit (CPG) that controls rhythmic movements of the gastric mill in the foregut of spiny lobster (Panulirus interruptus). 2. The majority of neurons in the gastric CPG are motor neurons (MNs) that innervate striated muscles of the gastric mill but that also make electrical and inhibitory chemical interconnections within the neuropil of the stomatogastric ganglion. We studied the ionic dependence, pharmacology, and time course of inhibitory postsynaptic potentials (IPSPs) evoked by two such MNs, the dorsal gastric (DG) and lateral gastric (LG), in their central synaptic partners. In the periphery, LG and DG are thought to release glutamate. 3. LG and DG evoke two types of IPSPs in follower neurons. The first, fast type of IPSP rises rapidly (the graded component within 100-300 ms, the spike-mediated components within a few tens of ms), is mediated by increased chloride and potassium conductances, and is blocked by or = 10 microM picrotoxin (PTX). These fast IPSPs closely resemble the glutamatergic IPSPs described in the pyloric circuit of the same ganglion. 4. The second, slow type of IPSP has a long rise time (1-2 s), is mediated by increased conductance to potassium (with little or no involvement of chloride), and is not blocked by 10 microM PTX, 5 mM tetraethylammonium chloride, or 0.1 mM scopolamine. These properties distinguish slow IPSPs from the forms of glutamatergic and cholinergic inhibition that have been described in the pyloric circuit. 5. Fast inhibition occurs alone at connections from DG and LG to power stroke MNs (median gastric and gastric mill). Slow inhibition occurs in parallel with fast inhibition (producing dual-component responses) at connections from LG to return stroke neurons [lateral posterior gastric MNs, (LPGs) and interneuron 1]. DG seems to evoke only a slow IPSP in LPGs. 6. The transmitter mediating the fast IPSPs is likely to be glutamate. We discuss possible mechanisms for the slow IPSP but have no evidence at present concerning the transmitter(s) involved. Slow inhibition is likely to be an important synaptic "building block" in the gastric CPG; it is "tuned" to the duration of gastric bursts and may contribute to the long cycle period of gastric rhythms.J Neurophysiol 1995745 1996-201197368838$Elson, R. C. Selverston, A. I.rkEvidence for a persistent Na+ conductance in neurons of the gastric mill rhythm generator of spiny lobsterscAnimal Lobsters/*physiology Membrane Potentials/drug effects Neural Conduction Neurons/*physiology Periodicity Sodium/*physiology Stomach/innervation Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacology Tetrodotoxin/pharmacologytEvidence for a persistent Na+ conductance was obtained in identified motor neurons of the gastric mill network in the stomatogastric ganglion of the spiny lobster Panulirus interruptus. The cells studied were the lateral gastric and lateral posterior gastric motor neurons, which in vivo control chewing movements of the lateral teeth of the gastric mill. We examined basic cellular properties in the quiescent network of the isolated stomatogastric ganglion. In current-clamp recordings, we found two types of evidence for a persistent Na+ conductance. First, tetrodotoxin-sensitive inward rectification occurred during depolarization from rest to spike threshold. Second, 5 mmol l-1 tetraethylammonium (a K+ channel blocker) induced plateau potentials that persisted in the presence of Mn2+ or a low [Ca2+]0 but were blocked by a low [Na+]0 or 100 nmol l-1 tetrodotoxin. The plateau potentials could drive trains of fast spikes in the motor axon and strong transmitter release at central output synapses within the ganglion. This conductance probably corresponds to the persistent Na+ current, INaP, described in cultured stomatogastric neurons and in neurons from several other preparations. During normal neuronal activity, it may contribute to the prolonged plateau depolarizations and long spike trains typical of motor neuronal activity during gastric rhythm generation. Persistent inward currents of this type are likely to be important in neurons that must fire prolonged bursts in cycle after cycle of rhythmical activity. J Exp Biol 1997 200i Pt 12n1795-807RLElson, R. C. Huerta, R. Abarbanel, H. D. Rabinovich, M. I. Selverston, A. I.^WDynamic control of irregular bursting in an identified neuron of an oscillatory circuit Animal Biological Clocks/physiology Digestive System/innervation Ganglia, Invertebrate/*physiology In Vitro Lobsters Membrane Potentials/physiology Neurons/*physiology Oscillometry Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiologyIn the oscillatory circuits known as central pattern generators (CPGs), most synaptic connections are inhibitory. We have assessed the effects of inhibitory synaptic input on the dynamic behavior of a component neuron of the pyloric CPG in the lobster stomatogastric ganglion. Experimental perturbations were applied to the single, lateral pyloric neuron (LP), and the resulting voltage time series were analyzed using an entropy measure obtained from power spectra. When isolated from phasic inhibitory input, LP generates irregular spiking-bursting activity. Each burst begins in a relatively stereotyped manner but then evolves with exponentially increasing variability. Periodic, depolarizing current pulses are poor regulators of this activity, whereas hyperpolarizing pulses exert a strong, frequency-dependent regularizing action. Rhythmic inhibitory inputs from presynaptic pacemaker neurons also regularize the bursting. These inputs 1) reset LP to a similar state at each cycle, 2) extend and further stabilize the initial, quasi-stable phase of its bursts, and 3) at sufficiently high frequencies terminate ongoing bursts before they become unstable. The dynamic time frame for stabilization overlaps the normal frequency range of oscillations of the pyloric CPG. Thus, in this oscillatory circuit, the interaction of rhythmic inhibitory input with intrinsic burst properties affects not only the phasing, but also the dynamic stability of neural activity.'|Department of Biology, Scripps Institution of Oceanography, University of California, San Diego, California 92093-0402, USA.10400940http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10400940 http://www.jn.org/cgi/content/full/82/1/115 http://www.jn.org/cgi/content/abstract/82/1/115J Neurophysiol 1999821115-22.r Dando1974 Dando1974 Dando1974 Dando1977 Davis1983"de Vente2001 Deitmer1993- DeKlotz2003 Dever2004 Dever2004DiCaprio2004% Dick20000} Dickinson1981 Dickinson1981 Dickinson1981| Dickinson1983 Dickinson1983~ Dickinson1988 Dickinson1988t Dickinson1989x Dickinson1989z Dickinson1990{ Dickinson1992y Dickinson1993u Dickinson1995v Dickinson1997w Dickinson2001 Dickinson2001W Dietel1999 Dindle1978Dircksen1999% Doshi1997Y Dreger2002X Dreger20034 Dybek2001 Edwards1984N Edwards2003 Edwards2004 Eigg1989? Eisen1981 Eisen1982' Eisen1984 Eisen1984u Eisen1984v Eisen19845 Eitner1997 El Manira1997 Elson1992 Elson1994 Elson1995 Elson1997& Elson1998 Elson1999 Elson2000B Elson2000 Elson2001 Elson2001 Elson2002 Epstein19908 Epstein1992 Epstein1992m Epstein1993Q Epstein1999 Evans1993Y Evers2002 Ewald1987 Ewer19868 Factor1981 Factor1982 Factor1989v Fairfield1997 Falcke2000% Farnham1997 Faumont1998 Faumont1998 Faumont2000G Felder1989H Felder1990 Felgenhauer1985 Felgenhauer1986 Felgenhauer1989 Fenelon1998 Fenelon1998 Fenelon1999# Fenelon19993 Fenelon19994 Fenelon2001 Fenelon2001 Fenelon2004Fickbohm1987' Flamm1984 Flamm1986 Flamm1986 Flamm1986 Flamm1987 Flamm1987 Flamm1989 Flamm1992 Fleischer1981 French2000 French2002 French2004I Friedi19911 Friend1976 Friesen1986 Frost1996Z Ganeshina2000 Garzino1992 Garzino1994 Gassie19797 Gassie19878 Gassie19939k Geffard1984E Geffard1987 Gibson1977 Gisselmann2003 Glasser1976 Glowik1997 Goaillard2004Godleski1999 Gola1981Goldberg1988 Goldman2001 Goldman2002 Golomb1993 Golowasch1986 Golowasch1989 Golowasch1990 Golowasch19918 Golowasch1992 Golowasch1992 Golowasch1992 Golowasch1992 Golowasch1992 Golowasch1993m Golowasch1993q Golowasch1996 Golowasch1997B Golowasch1998 Golowasch1999 Golowasch1999 Golowasch1999w Golowasch1999h Golowasch2000 Golowasch2001 Golowasch2002I Golowasch2003 Gossard1997 Govind1975 Govind19766 Govind1977 Govind1978 Govind1987 Govind1993E Govind20002# Goy1996Graubard1978Graubard1979Graubard1980Graubard1983Graubard1985>Graubard19878Graubard1987Graubard1987Graubard1988Graubard1989Graubard1991Graubard1992Graubard1993Graubard1995KGraubard19959#Graubard1996MGraubard1997Graubard1998!Graubard1998Graubard2000"Graubard2001NGraubard2003Graubard2003Graubard20040 Greenberg2005Griffith1998Grossman1983 Guckenheimer1993 Guckenheimer1993 Guckenheimer19959 Guckenheimer19959 Guckenheimer1997 Guckenheimer1997 Guckenheimer2003 Gueron1993r Gueron1993r Gueron1995r Gueron19959Gutovitz2001 Hall19901 Hall19911O Hall19941 Harness2002'Harris-Warrick1984Harris-Warrick1986Harris-Warrick1986Harris-Warrick1986Harris-Warrick1987Harris-Warrick1987Harris-Warrick1987Harris-Warrick1988Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1991Harris-Warrick1991Harris-Warrick1991Harris-Warrick1992Harris-Warrick1992Harris-Warrick1992 Harris-Warrick1992!Harris-Warrick1992Harris-Warrick1992Harris-Warrick1993Harris-Warrick1993Harris-Warrick1993Harris-Warrick1993Harris-Warrick1994Harris-Warrick1994Harris-Warrick1994Harris-Warrick1994Harris-Warrick1995Harris-Warrick1995Harris-Warrick1995Harris-Warrick1995Harris-Warrick1995Harris-Warrick1996Harris-Warrick1996 Fenelon2001Fickbohm1987' Flamm1984 Flamm1986 Flamm1986 Flamm1986 Flamm1987 Flamm1987 Flamm1989 Flamm1992 Fleischer1981 French2000̚ French2002̛ French2004I Friedi19911 Friend1976̝ Friesen1986 Frost1996 Garzino1992 Garzino1994 Gassie19797 Gassie19878 Gassie19939k Geffard1984E Geffard1987 Gibson1977̠ Glasser1976 Glowik1997̢ Gola1981̣Goldberg1988̤ Goldman2001 Goldman2002 Golomb1993 Golowasch1986 Golowasch1990 Golowasch19918 Golowasch1992 Golowasch1992 Golowasch1992 Golowasch1992 Golowasch1993m Golowasch1993 Golowasch1997B Golowasch1998 Golowasch1999 Golowasch1999 Golowasch1999 Golowasch2001 Golowasch2002I Golowasch2003 Govind1975 Govind19766 Govind1977 Govind1978̱ Govind1987 Govind1993̲Graubard1978̳Graubard1979̶Graubard1980̷Graubard1983̸Graubard1985>Graubard19878Graubard1987Graubard1988̵Graubard1991Graubard1992Graubard1995KGraubard19959MGraubard1997Graubard1998Graubard2000NGraubard2003̥ Guckenheimer1993̹ Guckenheimer1993 Guckenheimer19959 Guckenheimer19959 Guckenheimer1997̻ Guckenheimer1997̥ Gueron1993r Gueron1993r Gueron1995r Gueron19959Gutovitz2001O Hall19941 Harness2002'Harris-Warrick1984̗Harris-Warrick1986̘Harris-Warrick1986Harris-Warrick1986̖Harris-Warrick1987Harris-Warrick1987Harris-Warrick1987̽Harris-Warrick1988̾Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989Harris-Warrick1989̿Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1990Harris-Warrick1991Harris-Warrick1991Harris-Warrick1991Harris-Warrick1992Harris-Warrick1992Harris-Warrick1992 Harris-Warrick1992!Harris-Warrick1992̹Harris-Warrick1993Harris-Warrick1993Harris-Warrick1993Harris-Warrick1993Harris-Warrick1994Harris-Warrick1994Harris-Warrick1994Harris-Warrick1995Harris-Warrick1995Harris-Warrick1995Harris-Warrick1996Harris-Warrick1996 *: <12205138883 2002 SephbInhibitory synchronization of bursting in biological neurons: dependence on synaptic time constant1166-76Using the dynamic clamp technique, we investigated the effects of varying the time constant of mutual synaptic inhibition on the synchronization of bursting biological neurons. For this purpose, we constructed artificial half-center circuits by inserting simulated reciprocal inhibitory synapses between identified neurons of the pyloric circuit in the lobster stomatogastric ganglion. With natural synaptic interactions blocked (but modulatory inputs retained), these neurons generated independent, repetitive bursts of spikes with cycle period durations of approximately 1 s. After coupling the neurons with simulated reciprocal inhibition, we selectively varied the time constant governing the rate of synaptic activation and deactivation. At time constants 400 ms), bursts became phase-locked in a fully overlapping pattern with little or no phase lag and a shorter period. During the in-phase bursting, the higher-frequency spiking activity was not synchronized. If the circuit lacked a robust periodic burster, increasing the time constant evoked a sharp transition from out-of-phase oscillations to in-phase oscillations with associated intermittent phase-jumping. When a coupled periodic burster neuron was present (on one side of the half-center circuit), the transition was more gradual. We conclude that the magnitude and stability of phase differences between mutually inhibitory neurons varies with the ratio of burst cycle period duration to synaptic time constant and that cellular bursting (whether periodic or irregular) can adopt in-phase coordination when inhibitory synaptic currents are sufficiently slow.'zInstitute for Nonlinear Science, University of California San Diego, La Jolla, California 92093-0402, USA. relson@ucsd.eduHAElson, R. C. Selverston, A. I. Abarbanel, H. D. Rabinovich, M. I.("22194507 0022-3077 Journal ArticleJ NeurophysiolZTAction Potentials/physiology Animal Biological Clocks/physiology Computer Simulation Electrophysiology Ganglia/physiology Lobsters Models, Neurological Neural Inhibition/*physiology Neurons/*physiology Oscillometry Pylorus/innervation Reaction Time/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiologylehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1220513890291044 Epstein, I. R. Marder, E.u81Multiple modes of a conditional neural oscillatorHAction Potentials Calcium/physiology *Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.We present a model for a conditional bursting neuron consisting of five conductances: Hodgkin-Huxley type time- and voltage-dependent Na+ and K+ conductances, a calcium activated voltage-dependent K+ conductance, a calcium-inhibited time- and voltage-dependent Ca++ conductance, and a leakage Cl- conductance. With an initial set of parameters (version S), the model shows a hyperpolarized steady-state membrane potential at which the neuron is silent. Increasing gNa and decreasing gCl, where gi is the maximal conductance for species i, produces bursts of action potentials (Burster N). Alternatively, an increase in gCa produces a different bursting state (Burster C). The two bursting states differ in the periods and amplitudes of their bursting pacemaker potentials. They show different steady-state I-V curves under simulated voltage-clamp conditions; in simulations that mimic a steady-state I-V curve taken under experimental conditions only Burster N shows a negative slope resistance region. Model C continues to burst in the presence of TTX, while bursting in Model N is suppressed in TTX. Hybrid models show a smooth transition between the two states. 1990 Biol Cybern631 25-34 Using Smart Source ParsingEwald, D.A. Barker, D.L. 1987Dopaminergic modulation of the lobster pyloric pacemaker potential is enhanced by concurrent inhibition of cyclic nucleotide phosphodiesterase "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag301-303 Factor, J.R. 1981rDevelopment and metamorphosis of the digestiv system of larval lobster, Homarus americanus (Decapoda: Nephropidae)HZ J Morphol 169225-242 Factor, J.R. 1982qDevelpment and metmorphosis of the feeding apparatus of the stone crab, Menippe mercenaria (Brachyura Xanthindae)AHZ J Morphol 1723299-312 Factor, J.R. 1989B;Development of the feeding apparatus in decapod crustaceans @9Felgenhauer, B.E. Watling, L. Thistle, A.B. Balkema, A.A.TMCrustacean Issues: Functional Morphology of Feeding and Grooming in Crustacea  Rotterdam  Brookfield6185-203ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10879435)^WFalcke, M. Huerta, R. Rabinovich, M. I. Abarbanel, H. D. Elson, R. C. Selverston, A. I. f`Modeling observed chaotic oscillations in bursting neurons: the role of calcium dynamics and IP3NGAction Potentials Animal Calcium/*metabolism Calcium Channels/metabolism Human Inositol 1,4,5-Trisphosphate/*metabolism Lobsters *Models, Biological Neurons/metabolism/*physiology Pylorus/innervation/metabolism/physiology Receptors, Cytoplasmic and Nuclear/metabolism Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Chaotic bursting has been recorded in synaptically isolated neurons of the pyloric central pattern generating (CPG) circuit in the lobster stomatogastric ganglion. Conductance-based models of pyloric neurons typically fail to reproduce the observed irregular behavior in either voltage time series or state-space trajectories. Recent suggestions of Chay [Biol Cybern 75: 419-431] indicate that chaotic bursting patterns can be generated by model neurons that couple membrane currents to the nonlinear dynamics of intracellular calcium storage and release. Accordingly, we have built a two-compartment model of a pyloric CPG neuron incorporating previously described membrane conductances together with intracellular Ca2+ dynamics involving the endoplasmic reticulum and the inositol 1,4,5-trisphosphate receptor IP3R. As judged by qualitative inspection and quantitative, nonlinear analysis, the irregular voltage oscillations of the model neuron resemble those seen in the biological neurons. Chaotic bursting arises from the interaction of fast membrane voltage dynamics with slower intracellular Ca2+ dynamics and, hence, depends on the concentration of IP3. Despite the presence of 12 independent dynamical variables, the model neuron bursts chaotically in a subspace characterized by 3-4 active degrees of freedom. The critical aspect of this model is that chaotic oscillations arise when membrane voltage processes are coupled to another slow dynamic. Here we suggest this slow dynamic to be intracellular Ca2+ handling.'ngMax Planck-Institute for the Physics of Complex Systems, Dresden, Germany. falcke@mpipks-dresden.mpg.def10879435 Biol Cyberna 2000826i517-27.r :onPirenzepine/pharmacologyPlastic EmbeddingPolymerase Chain Reaction Potassium Channel Blockers,'Potassium Channels/*genetics/metabolism$Potassium Channels/*physiology40Potassium Channels/analysis/genetics/*physiology0+Potassium Channels/drug effects/*physiology0*Potassium Channels/drug effects/metabolism,'Potassium Channels/genetics/*metabolism Potassium Channels/metabolism Potassium Channels/physiologyPotassium/*physiologyPotassium/metabolism$!Potassium/metabolism/pharmacologyPotassium/pharmacologyPotassium/physiologyPrecipitin TestsPredictive Value of Tests$!Presynaptic Terminals/*physiology40Presynaptic Terminals/*physiology/ultrastructure(%Presynaptic Terminals/*ultrastructure4/Presynaptic Terminals/metabolism/ultrastructure$ Presynaptic Terminals/physiologyProcaine/pharmacologyProglumide/pharmacology Proprioception/*physiology($Protein Isoforms/genetics/metabolism Protein Kinase C/metabolismPsychomotor Performance("Psychomotor Performance/physiologypurification/*physiology Purkinje Cells/*physiology Pyloric Antrum/*innervation Pyloric Antrum/*physiology Pyloric Antrum/innervationpyloric pattern PylorusPylorus/*innervation$Pylorus/*innervation/physiologyPylorus/*physiology Pylorus/cytology/*innervation Pylorus/cytology/drug effects,'Pylorus/cytology/innervation/physiologyPylorus/drug effects$ Pylorus/drug effects/innervation$Pylorus/drug effects/physiologyPylorus/innervation$Pylorus/innervation/*physiology,)Pylorus/innervation/metabolism/physiology$Pylorus/innervation/physiologyPylorus/physiology Quisqualic Acid/pharmacology RabbitsRadioimmunoassayRats Reaction TimeReaction Time/physiologyReceptors, Cholinergic($Receptors, Cholinergic/*drug effects4.Receptors, Cholinergic/drug effects/physiology0-Receptors, Cytoplasmic and Nuclear/metabolism$Receptors, Dopamine/*metabolismD>Receptors, GABA-B/agonists/antagonists & inhibitors/metabolism@7Voltage clamp analysis of intact stomatogastric neurons&Animal Calcium Channels/drug effects Electrophysiology Ion Channels/drug effects Lobsters/*physiology Neurons/*physiology Pylorus/innervation Stomach/*innervation Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacology Tetrodotoxin/pharmacology 4-Aminopyridine/pharmacology.Two-electrode voltage clamp of intact, identified pyloric neurons of the spiny lobster stomatogastric ganglion reveals two major outward currents. A rapidly inactivating, tetraethylammonium- (TEA) insensitive, 4-aminopyridine- (4AP) sensitive, outward current resembles IA of molluscan neurons; it activates rapidly on depolarizations above rest (e.g. -45 mV), delaying both the axonal- sodium and the neuropil-calcium spikes which escape voltage-clamp control. We infer that A-current is distributed both in a space clamped region (on or near the soma) and in a non-space clamped region with access to the generators for sodium and calcium spikes. A calcium- dependent outward current, IO(Ca), activates rapidly at clamp steps above -25 mV and inactivates at depolarizing holding voltages. Increasing depolarization results in an increase in both IO(Ca) and firing rate but a reduction in the amplitude of the sodium spike current. Blockage of IO(Ca) with Cd2+ causes little change in spike firing pattern. These observations are consistent with IO(Ca) being activated primarily in the soma and nearby regions which are under good control with a soma voltage clamp (and distant from the Na(+)-spike trigger zone). While the lack of space clamp limits resolution of charging transients and tail currents, the identification of the major current subgroups can still be readily accomplished, and inferences about the location and function of currents can be made which would not be possible if the cells were space clamped or truncated. Brain Rest 1991 557e 1-2n 241-5415356180932 2005 FebanhSynaptic depression in conjunction with a-current channels promote phase constancy in a rhythmic network 656-77In many central pattern generators, pairs of neurons maintain an approximately fixed phase despite large changes in the frequency. The mechanisms underlying phase maintenance are not clear. Previous theoretical work suggested that inhibitory synapses that show short-term depression could play a critical role in this respect. In this work we examine how the interaction between synaptic depression and the kinetics of a transient potassium (A-like) current could be advantageous for phase constancy in a rhythmic network. To demonstrate the mechanism in the context of a realistic central pattern generator, we constructed a detailed model of the crustacean pyloric circuit. The frequency of the rhythm was modified by changing the level of a ligand-activated current in one of the pyloric neurons. We examined how the time difference of firing activities between two selected neurons in this circuit is affected by synaptic depression, A-current, and a combination of the two. We tuned the parameters of the model such that with synaptic depression alone, or A-current alone, phase was not maintained between these two neurons. However, when these two components came together, they acted synergistically to maintain the phase across a wide range of cycle periods. This suggests that synaptic depression may be necessary to allow an A-current to delay a postsynaptic neuron in a frequency-dependent manner, such that phase invariance is ensured.r'|Life Sciences Dept., Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, Israel 84105. yairman@bgumail.bgu.ac.il).Greenberg, I. Manor, Y.y 0022-3077 Journal Article J Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15356180 9407791281Guckenheimer, J. Gueron, S. Harris-Warrick, R. M.a0)Mapping the dynamics of a bursting neuroniAction Potentials Animal Electrophysiology Ganglia, Invertebrate/physiology Ion Channels/metabolism *Models, Neurological Neurons/drug effects/*physiology Potassium Channels/drug effects/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. 4-Aminopyridine/pharmacologyThe anterior burster (AB) neuron of the lobster stomatogastric ganglion displays varied rhythmic behavior when treated with neuromodulators and channel-blocking toxins. We introduce a channel-based model for this neuron and show how bifurcation analysis can be used to investigate the response of this model to changes of its parameters. Two dimensional maps of the parameter space of the model were constructed using computational tools based on the theory of nonlinear dynamical systems. Changes in the intrinsic firing and oscillatory properties of the model AB neuron were correlated with the boundaries of Hopf and saddle-node bifurcations on these maps. Complex rhythmic patterns were observed, with a bounded region of the parameter plane producing bursting behavior of the model neuron. Experiments were performed by treating an isolated AB cell with 4-aminopyridine which selectively reduces gA, the conductance of the transient potassium channel. The model accurately predicts the qualitative changes in the neuronal voltage oscillations that are observed over a range of reduction of gA in the neuron. These results demonstrate the efficacy of dynamical systems theory as a means of determining the varied oscillatory behaviors inherent in a channel- based neural model. Further, the maps of bifurcations provide a useful tool for determining how these behaviors depend upon model parameters and comparing the model to a real neuron.("Philos Trans R Soc Lond B Biol Sci 1993 341t 1298 345-59 (!Golowasch, J. Manor, Y. Nadim, F.m82Recognition of slow processes in rhythmic networksAnimal Calcium Signaling/physiology Human Models, Neurological Nerve Net/*physiology Neural Inhibition/physiology Neuronal Plasticity/*physiology *Periodicity Synaptic Transmission/*physiology'TNVolen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA.10441293http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10441293 http://www.biomednet.com/library/fulltext/TINS.etd00119_01662236_v0022i09_00001466 http://www.biomednet.com/library/abstract/TINS.etd00119_01662236_v0022i09_00001466NTrends Neurosci  1999229n 375-7.<5Golowasch, J. Goldman, M. S. Abbott, L. F. Marder, E. RLFailure of averaging in the construction of a conductance-based neuron modelAction Potentials/physiology Animal Crabs Ganglia, Invertebrate/cytology/physiology *Models, Neurological Neurons/*physiology Potassium/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.,%Parameters for models of biological systems are often obtained by averaging over experimental results from a number of different preparations. To explore the validity of this procedure, we studied the behavior of a conductance-based model neuron with five voltage- dependent conductances. We randomly varied the maximal conductance of each of the active currents in the model and identified sets of maximal conductances that generate bursting neurons that fire a single action potential at the peak of a slow membrane potential depolarization. A model constructed using the means of the maximal conductances of this population is not itself a one-spike burster, but rather fires three action potentials per burst. Averaging fails because the maximal conductances of the population of one-spike bursters lie in a highly concave region of parameter space that does not contain its mean. This demonstrates that averages over multiple samples can fail to characterize a system whose behavior depends on interactions involving a number of highly variable components.0'Volen Center for Complex Systems and Department of Biology, Brandeis University, Waltham, MA 02454, USA. golowasch@stg.rutgers.edu11826077J Neurophysiol 2002872 1129-31.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11826077 http://jn.physiology.org/cgi/content/full/87/2/1129 http://jn.physiology.org/cgi/content/abstract/87/2/1129 .'Govind, C.K. Atwood, H.L. Maynard, D.M. 1975piInnervation and neuronmuscular physiology of intrinsic foregut muscles in the blue crab and spiny lobsterJ Comp Physiol96185-204 Govind, C.K. Lingle, C.J. 19872+Neuromuscular organization and pharmacology "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag 31-48 Animal78244172 Graubard, K.rkSynaptic transmission without action potentials: input-output properties of a nonspiking presynaptic neuronAnimal Lobsters Membrane Potentials Neural Inhibition Neurons/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiology *Synaptic Transmission 1. Input-output properties of the inhibitory synaptic connection between non-spiking neurons (EX1) and gastric mill (GM) neurons were examined in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. Current was injected into and the voltage was recorded during current injection, two independent microelectrodes were used. 2. The EX1-GM synaptic connection is a conductance-increase inhibitory type, with an input-output curve that resembles the curve for the squid giant synapse. There is a threshold level of depolarization for transmitter release from the presynaptic cell. Beyond that threshold, increasing presynaptic depolarization causes increasing postsynaptic hyperpolarization (and inhibition). 3. A long presynaptic current step always causes a postsynaptic response with an initial peak of hyperpolarization followed by a decay to a less hyperpolarized plateau level. The plateau level is maintained, in most cells, for the duration of the presynaptic depolarization even over long periods (30 s). 4. The peak, but not the plateau, part of the postsynaptic response is sensitive to the past history of the synaptic connection. If a large conditioning pulse is applied to the presynaptic cell causing a large postsynaptic hyperpolarization, then the postsynaptic response to a later presynaptic test depolarization will have a reduced peak, leaving the plateau component unchanged.J Neurophysiol 1978414s1014-25p Graubard, K. Calvin, W.H. 1979d]Presynaptic dentrites: Implications of spikeless synaptic transmission and dendritic geometry Schmitt, F.O. Worden, F.G..'The Neurosciences: Fourth Study Program  Cambridge, MA  MIT Press317-331810139590)Graubard, K. Raper, J. A. Hartline, D. K. :4Graded synaptic transmission between spiking neurons$Action Potentials Animal Electrophysiology Ganglia/*physiology Lobsters Membrane Potentials Neural Inhibition Neurons/physiology Neurotransmitters/*secretion Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology *Synaptic Transmission Tetrodotoxin/pharmacologyGraded synaptic transmission occurs between spiking neurons of the lobster stomatogastric ganglion. In addition to eliciting spike-evoked inhibitory potentials in postsynaptic cells, these neurons also release functionally significant amounts of transmitter below the threshold for action potentials. The spikeless postsynaptic potentials grade in amplitude with presynaptic voltage and can be maintained for long periods. Graded synaptic transmission can be modulated by synaptic input to the presynaptic neuron.eProc Natl Acad Sci U S A 1980776i 3733-5 D  Greenberg, I.Greenspan, R.J.Griffith, L. C. Grillner, S.Grossman, R. I.Guckenheimer, J. Gueron, S. Gutovitz, S. Hall, C. Hall, W. M. Hall, Z.H. Hanson, S.J.Harness, P. I.Harris-Warrick, R.Harris-Warrick, R. M.Harris-Warrick, R.M.Hartenstein, V.Hartline, D. K.Hartline, D.K. Hatt, H. Hauptman, J.Heinzel, H. G. Helluy, S. M. Hemple, C.M. Herbert, E. Herman, R.M. Hermann, A. Hetling, J.Hetling, J. R.Hildebrand, J. G. Hinton, D.J. Hirji, R. Hobbs, K. H. Hooper, N.K. Hooper, S. L. Hooper, S.L Hooper, S.L. Hoover, N. J. Hoyle, G. Hucho, F. Huerta, R. Hughes, S. Hurley, L. M. Icely, J.D. Jackel, C. Jacklet, J.Jahromi, S. S.Johannen, K.C.Johnson, B. R. Johnson, B.R. Jones, B. R. Jones, B.R.Jorge-Rivera, J.Jorge-Rivera, J. C.Jorge-Rivera, J.C. Kappen, B.Kater Katz, P. S. Katz, P.S. Kebabian, J. Kehoe, J. Keller, R. Kelley, D. Kelley, W. P. Kelson Kennedy, D.Kennedy, M. B. Kennedy, M.B. Kepler, T. B. Kepler, T.B. Kiehn, O. Kien, J. Kilman, V. Kilman, V. L. Kim, M. Kim, M.T. King, D. G. Kirk, M.D. Kittaka, J. Kjaerulff, O.Kloppenburg, P. Koch, C.Konstant, P. H. Kopell, N. Kordon, C.Kravitz, E. A. Krenz, W. Krenz, W. D. Krenz, W.-D. Kumar, W. Kunze, J.C. Kushner, P.D. Kwan, I.Kyriacou, C.P. Labenia, J. Lange, A. B.Lanning, C. C. Lanning, C.C.Larimer, J. L.Laverack, M. S.Laverack, M.S. Le Feuvre, Y. Le Moal, M. Legeay, A. Leger, C.L. LeMasson, G. Lengvari, I. Levi, R. Levini, M.T. Levini, R. M. Levini, R.M. Li, L. Lin, M. Lingle, C. Lingle, C. J. Lingle, C.J.Lippmann, R.P. Liu, Z.Lnenicka, G. A. LoFaro, T. Lovett, D.L. Lubell, J.K. Lubics, A.Lundquist, C. T. Luther, J. A.MacLean, J. N.Macmillan, D.L. Mahadevan, A. Mamiya, A.Mancillas, J. R. Mandell Manhas, A. S. Mann, K.H. Manor, Y. Mantel, L.H. Marder, E. Marder, Y. E. Marin, L.Masinovsky, B.Massabuau, J. C. Matly, M.Maynard, D. M. Maynard, D.M. Maynard, E.A. Mayrand, P. Mazzoni, P. McCollum, G. McCrohan, C. McKenna, T.M. Mecsas, C. Meier, T. Meiss, D.E. Menzel, R. Mercier, J. Meseke, M. Messai, E. Meunier, C. Meyrand, .M. Meyrand, P.Miall Miller, J. P. Miller, J.P. Miller, W. L. Mira, M. Mitchison Mittmann, B. Miyatani, M. Miyazaki, T. Mizrahi, A.Mocquard, M.F. Moody, J.E.Moriarty, D.J.W. Morris, J. Morris, L. G. Mortin, L. I.Moskowitz, H.S. Moulins, M Moulins, M.Moulins, Maurice Moulins, S. Mulloney, B. Muren, J. E. Nadim, F. Nagy, E. Nagy, F.Nakanishi, S. T. Nakemura, K. Nargeot, R. Nassel, D. R.Nathanson, J.A. Nemoto, T. Nguyen, D. Nicholson Nishida, S. Nold, K. A. Nonnotte, L. Norman, R.S. Norris, B. J. Nott, J.A.Nozdrachev, A. D.Nusbaum, M. P. Nusbaum, M.P. O'Neil, M. O'Neil, M. B. O'Neil, M.B. Ogden, L. Oliva, R. Olivera, B.M. Orchard, I.Orlovsky, G.N. Oshinsky, M. Panchin, Y.Panchin, Y. V. Parker, T.J.Patwardhan, S.S. L N87282572("Harris-Warrick, R. M. Flamm, R. E.F@Multiple mechanisms of bursting in a conditional bursting neuronAnimal Biogenic Amines/*physiology Calcium/physiology Digestive System/innervation Dopamine/physiology Lobsters/*physiology Membrane Potentials/drug effects Nervous System/drug effects/*physiology *Nervous System Physiology Neurons/drug effects/*physiology Octopamine/physiology Serotonin/physiology Sodium/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacology Tetrodotoxin/pharmacologyv@:The anterior burster (AB) neuron in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus, is a conditional burster in the pyloric motor circuit. Bath application of the monoamines dopamine, serotonin, and octopamine induces rhythmic bursting pacemaker potentials in a silent, synaptically isolated AB cell. However, each amine produces a unique and characteristic burst shape, resulting from different ionic dependences of the burst mechanisms. Bursting induced by serotonin or octopamine is critically dependent upon sodium entry through tetrodotoxin-sensitive channels; dopamine-induced bursting is not TTX-sensitive. Dopamine-induced bursting is abolished when extracellular calcium is reduced to 25% of normal; serotonin- and octopamine-induced bursts continue in this saline, although they are abolished in salines with calcium reduced to 10% or less of normal. Quantitative differences between the amines are also seen in the tetraethylammonium (TEA) sensitivity of the burst amplitude and in the dependence of the interburst hyperpolarization on extracellular potassium. These experiments demonstrate that there are both quantitative and qualitative differences in the ionic currents underlying every phase of the bursts induced by the 3 amines. Thus, a single neuron can burst via more than one ionic mechanism. J Neurosci 19877x7u2113-28s87300801*$Harris-Warrick, R. M. Johnson, B. R.ZTPotassium channel blockade induces rhythmic activity in a conditional burster neurond]Action Potentials/drug effects Aminopyridines/pharmacology Animal Apamin/pharmacology Calcium/*physiology Digestive System/innervation Ion Channels/drug effects/*physiology Lobsters/*physiology Neurons/drug effects/*physiology Potassium/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacology/In the lobster stomatogastric ganglion the Anterior Burster (AB) neuron loses its rhythmic bursting capabilities when isolated from all synaptic input. Here we report that compounds which reduce the current through several different types of potassium channels induce bursting in isolated AB neurons. These results suggest that when quiescent, this neuron has all the conductances necessary to support bursting, but bursting is actively inhibited by tonic potassium conductances.p Brain Rese 1987 416a2l 381-6rHarris-Warrick, R.M. 198881Chemical modulation of central pattern generators ,&Cohen, A.H. Rossignol, S. Grillner, S.*$Neural Control of Rhythmic Movements New York John Wiley & Sonsi285-331y89303527Harris-Warrick, R. M.shbForskolin reduces a transient potassium current in lobster neurons by a cAMP-independent mechanismAnimal Cyclic AMP/*physiology Forskolin/analogs & derivatives/*pharmacology Ganglia/drug effects/metabolism/*physiology Lobsters/*physiology Membrane Potentials/drug effects Potassium Channels/*physiology Support, U.S. Gov't, P.H.S.Forskolin decreases the transient potassium current, IA, in voltage- clamped somata of identified neurons in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. The diterpene reduces the peak outward current and accelerates the rate of inactivation of IA. Forskolin has no detectable effects on two other identifiable potassium currents in these cells, IK(Ca) and IK(V). Three identified stomatogastric neuron types (PD, PY, AB) have marked amounts of IA which are affected by forskolin; three other cell types (LP, IC, VD) have little or no IA, and forskolin has no effect on their outward currents. Bath application of 8-bromo-cAMP, N,N-dibutyryl-cAMP and IBMX do not affect IA. In addition, the forskolin analog, 1,9- dideoxyforskolin, which does not activate adenylate cyclase, mimics forskolin's effects on IA. Thus, the effects of forskolin on IA are not mediated by cAMP elevation. Brain Res 1989 4891 59-66@9Harris-Warrick, R.M. Flamm, R.E. Johnson, B.R. Katz, P.S. 19890*Modulation of neural circuits in crustaceaAm Zool29 1305-1320("Harris-Warrick, R.M. Johnson, B.R. 1989RLMotor pattern networks: Flexible foundations for rhythmic pattern production Carew, T. Kelley, D.0*Perpectives in Neural Systems and Behavior New York  Alan R. Liss 51-71iHarris-Warrick, R.M. 1990BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MA  MIT Press 87-13894169638Harris-Warrick, R. M.0Pattern generationAnimal Behavior, Animal/*physiology Models, Neurological Nerve Net/*physiology Neurons/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.rSignificant advances have been made in understanding the cellular mechanisms for pattern generation in both invertebrate and vertebrate preparations. In a number of preparations, slow neuromodulators have been shown not only to modify network function, but to be intimately involved in development and/or normal function of the neural network and its associated behavior. The mechanisms underlying coordination between multiple pattern-generating networks, including switching of neurons from one network to another, are now being studied. Several new quantitative models of network function have been developed, and modeling is now an important component of research in this field.Curr Opin NeurobiolP 19933a6A 982-8oHarris-Warrick, R.M. 1994TNModulation of small neural networks in the crustacean stomatogastric ganglion "Selverston, A.I. Ascher, P.JCCellular and Molecular Mechanisms Underlying Higher Neural Function New York John Wiley & Sons111-126p Biogenic Amines/*physiology97401429>7Guckenheimer, J. Harris-Warrick, R. Peck, J. Willms, A.<5Bifurcation, bursting, and spike frequency adaptation,Action Potentials/*physiology Adaptation, Physiological Animal Ganglia, Autonomic/physiology Gastrointestinal System/physiology Lobsters/physiology *Neural Networks (Computer) Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.3Many neural systems display adaptive properties that occur on time scales that are slower than the time scales associated with repetitive firing of action potentials or bursting oscillations. Spike frequency adaptation is the name given to processes that reduce the frequency of rhythmic tonic firing of action potentials, sometimes leading to the termination of spiking and the cell becoming quiescent. This article examines these processes mathematically, within the context of singularly perturbed dynamical systems. We place emphasis on the lengths of successive interspike intervals during adaptation. Two different bifurcation mechanisms in singularly perturbed systems that correspond to the termination of firing are distinguished by the rate at which interspike intervals slow near the termination of firing. We compare theoretical predictions to measurement of spike frequency adaptation in a model of the LP cell of the lobster stomatogastric ganglion.J Comput Neurosci 199743 257-77 Guckenheimer, J. Rowat, P. 1997:4Dynamical systems analysis of real neuronal networks >8Stein, P.S.G. Grillner, S. Selverston, A.I. Stuart, D.G.*$Neuron, Networks, and Motor Behavior  Cambridge, MA  MIT Press151-163 XJDGutovitz, S. Birmingham, J. T. Luther, J. A. Simon, D. J. Marder, E.HAGABA enhances transmission at an excitatory glutamatergic synapseeAnimal Baclofen/pharmacology Electric Stimulation Excitatory Postsynaptic Potentials/drug effects/physiology Female GABA Agonists/pharmacology GABA Antagonists/pharmacology Ganglia, Invertebrate Glutamic Acid/*metabolism/pharmacology In Vitro Iontophoresis Lobsters Male Membrane Potentials/drug effects/physiology Motor Neurons/drug effects/metabolism Muscimol/pharmacology Muscles/innervation/physiology Neuromuscular Junction/drug effects/metabolism Patch-Clamp Techniques Picrotoxin/pharmacology Receptors, GABA-B/agonists/antagonists & inhibitors/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/drug effects/*metabolism Synaptic Transmission/drug effects/*physiology gamma-Aminobutyric Acid/*metabolism/pharmacology`YGABA mediates both presynaptic and postsynaptic inhibition at many synapses. In contrast, we show that GABA enhances transmission at excitatory synapses between the lateral gastric and medial gastric motor neurons and the gastric mill 6a and 9 (gm6a, gm9) muscles and between the lateral pyloric motor neuron and pyloric 1 (p1) muscles in the stomach of the lobster Homarus americanus. Two-electrode current- clamp or voltage-clamp techniques were used to record from muscle fibers. The innervating nerves were stimulated to evoke excitatory junctional potentials (EJPs) or excitatory junctional currents. Bath application of GABA first decreased the amplitude of evoked EJPs in gm6a and gm9 muscles, but not the p1 muscle, by activating a postjunctional conductance increase that was blocked by picrotoxin. After longer GABA applications (5-15 min), the amplitudes of evoked EJPs increased in all three muscles. This increase persisted in the presence of picrotoxin. beta-(Aminomethyl)-4-chlorobenzenepropanoic acid (baclofen) was an effective agonist for the GABA-evoked enhancement but did not increase the postjunctional conductance. Muscimol activated a rapid postsynaptic conductance but did not enhance the amplitude of the nerve-evoked EJPs. GABA had no effect on iontophoretic responses to glutamate and decreased the coefficient of variation of nerve-evoked EJPs. In the presence or absence of tetrodotoxin, GABA increased the frequency but not the amplitude of miniature endplate potentials. These data suggest that GABA acts presynaptically via a GABA(B)-like receptor to increase the release of neurotransmitter.'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.11487616 J Neurosci 200121165935-43.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11487616 http://www.jneurosci.org/cgi/content/full/21/16/5935 http://www.jneurosci.org/cgi/content/abstract/21/16/5935& Harris-Warrick, R.M. Flamm, R.E. 1986F@Chemical modulation of a small central pattern generator circuit TINS9432-437 fXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9292972Hartenstein, V.i>7Development of the insect stomatogastric nervous system Animal Enteric Nervous System/*physiology Ganglia, Invertebrate/physiology Insects/*physiology Stomach/*innervation Support, U.S. Gov't, P.H.S.nhbThe stomatogastric nervous system (SNS) forms a network of peripheral ganglia associated with the insect gut. The SNS originates from a neuroepithelial placode which dissolves into a population of migrating neural precursors. The formation of the SNS presents many parallels to the development of the vertebrate peripheral nervous system. Recent studies have started to provide answers for pertinent questions in SNS development, in particular, how the SNS placode is specified, how SNS precursors are released in a reproducible pattern from this placode and how different cell types in the SNS are determined.'piDept of Molecular, Cell and Developmental Biology, University of California, Los Angeles 90095-1606, USA.r9292972sTrends Neurosciv 1997209o 421-7.76096421$Hartline, D. K. Maynard, D. M.RLMotor patterns in the stomatogastric ganglion of the lobster Panulirus argusAnimal Ganglia/*physiology In Vitro Lobsters/*physiology Motor Neurons/*physiology Muscles/physiology Stomach/innervation/physiology/surgery Support, U.S. Gov't, P.H.S. Synaptic Transmission 1. Acitivity patterns arising from the thirty cells of the stomatogastric ganglion of Panulirus argus are described for both a semi-intact preparation and an isolated one. 2. The thirty or so cells can be divided so far into two functional groupings: the gastric mill group, with at least ten motor elements, and the pyloric group with at least fourteen. There is some, but not extensive, interaction between groups. 3. The main gastric mill activity is arranged in two sets of elements, each of which is composed of reciprocating elements innervating antagonistic muscles. Thus alternation in activity between the single LC and the two LG neurones results in alternate closing and opening of the lateral teeth; alternation between the four GM and single CP units results in alternate protraction and retraction of the medial tooth. 4. The two sets are phased to each other in such a way that they cause gastric mill teeth to operate effectively to masticate food. 5. The main pyloric activity is arranged in a three-part cycle with each of three sets of units active in sequence. Activity in two PD and one AB unit is followed by bursts in IC and LP units followed in turn by activity in up to seven PY units. Activity in a single VD neurone is locked to this cycle in a more complex pattern.f J Exp Biol 1975622  405-2080043198Hartline, D. K. lePattern generation in the lobster (Panulirus) stomatogastric ganglion. II. Pyloric network simulationD>Animal Electric Stimulation Ganglia/*physiology Lobsters Membrane Potentials *Models, Neurological Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Neurons/*physiology Pylorus/*innervation Stomach/innervation Support, U.S. Gov't, P.H.S. Synapses/physiology Synaptic Transmission Time Factors 1. Results from the companion paper were incorporated into a physiologically realistic computer model of the three principal cell types (PD/AB, LP, PY) of the pyloric network in the stomatogastric ganglion. Parameters for the model were mostly calculated (sometimes estimated) from experimental data rather than fitting the model to observed output patterns. 2. The initial run was successful in predicting several features of the pyloric pattern: the observed gap between PD and LP bursts, the appropriate sequence of the activity periods (PD, LP, PY), and a substantial PY burst not properly simulated by an earlier model. 3. The major discrepancy between model and observed patterns was the too-early occurrence of the PY burst, which resulted in a much shortened LP burst. Motivated by this discrepancy, additional investigations were made of PY properties. A hyperpolarization-enabled depolarization-activated hyperpolarizing conductance change was discovered which may make an important contribution to the late phase of PY activity in the normal burst cycle. Addition of this effect to the model brought its predictions more in line with observed patterns. 4. Other discrepancies between model and observation were instructive and are discussed. The findings force a substantial revision in previously held ideas on pattern production in the pyloric system. More weight must be given to functional properties of individual neurons and less to properties arising purely from network interactions. This shift in emphasis may be necessary in more complicated systems as well. 5. An example has been provided of the value quantitative modeling can be to network physiology. Only through rigorous quantitative testing can qualitative theories of how the nervous system operates be substantiated. Biol Cybern 1979334 223-36 IlrGastrointestinal Motility,'Gastrointestinal Motility/*drug effects(%Gastrointestinal Motility/*physiology82Gastrointestinal Motility/drug effects/*physiology($Gastrointestinal Motility/physiology40Gastrointestinal System/*drug effects/physiology($Gastrointestinal System/*innervation(#Gastrointestinal System/*physiology(#Gastrointestinal System/innervation4/Gastrointestinal System/innervation/*physiology4.Gastrointestinal System/innervation/physiology("Gastrointestinal System/physiology GastroscopyGene Expression82Gene Expression Regulation, Enzymologic/physiology,'Gene Expression/drug effects/physiology Gene Expression/physiology($Gills/anatomy & histology/physiologyGills/physiologyGlucose/pharmacologyGlutamates/*pharmacologyGlutamates/*physiologyGlutamates/metabolismGlutamates/pharmacology("Glutamates/pharmacology/physiologyGlutamates/physiology,&Glutamic Acid/*metabolism/pharmacology Glutamic Acid/*pharmacologyGlutamic Acid/*physiology(%Glutamic Acid/pharmacology/physiology Glycopeptides/pharmacology("Glycoproteins/*analysis/immunologyGrasshoppers/*physiology85GTP-Binding Protein alpha Subunits, Gq-G11/metabolism85Guanylate Cyclase/antagonists & inhibitors/metabolism Guanylate Cyclase/metabolism Guinea Pigs("Heart Conduction System/physiology$Heart/drug effects/*physiology Heart/embryology/innervationHeart/innervation Heart/innervation/physiologyHeart/physiologyHeat Hemicholinium 3/pharmacologyHemolymph/chemistry$Hemolymph/immunology/metabolismHemolymph/metabolismHistamine/*analysis<8Histamine/administration & dosage/*metabolism/physiologyHistamine/metabolism("Histamine/pharmacology/*physiologyHistocytochemistryHistological Techniques$History of Medicine, 20th Cent. HomeostasisHomeostasis/*physiologyHoof and Claw/innervationHorseradish Peroxidase("Horseradish Peroxidase/*metabolism Horseshoe Crabs/*physiologyHorseshoe Crabs/chemistryHuman Humans Ibotenic Acid/pharmacologyImmobilizationImmune Sera/immunologyImmunochemistryImmunoenzyme TechniquesImmunohistochemistry Immunohistochemistry/methodsImmunologic Techniques In Vitro Inhibitioninhibitors/*drug effects Injections,(Inositol 1,4,5-Trisphosphate/*metabolism,(Insect Hormones/*pharmacology/physiology,'Insect Hormones/metabolism/pharmacology Insects$Insects/*metabolism/physiologyInsects/*physiologyInterneurons/*chemistryInterneurons/*physiology($Interneurons/drug effects/physiologyInterneurons/physiology,&Interneurons/physiology/ultrastructure(#interruptus stomatogastric ganglion intersegmental coordinationIntestines/innervation$!Intestines/innervation/physiology(#Invertebrate Hormones/*pharmacology$!Invertebrate Hormones/*physiology$Invertebrate Hormones/analysis0-Invertebrate Hormones/metabolism/pharmacology("Invertebrate Hormones/pharmacology InvertebratesInvertebrates/*chemistryInvertebrates/*physiologyInvertebrates/physiology Ion Channel Gating/physiology Ion Channels/*drug effectsIon Channels/*physiology41Ion Channels/antagonists & inhibitors/*metabolismIon Channels/drug effects(%Ion Channels/drug effects/*physiology($Ion Channels/drug effects/metabolism($Ion Channels/drug effects/physiologyIon Channels/metabolismIon Channels/physiologyIonsIons/*metabolism Iontophoresis Isoquinolinesb"\97143370VOHarris-Warrick, R. M. Coniglio, L. M. Levini, R. M. Gueron, S. Guckenheimer, J.tnDopamine modulation of two subthreshold currents produces phase shifts in activity of an identified motoneuronAnimal Differential Threshold Dopamine/pharmacology/*physiology Electric Conductivity Ganglia, Invertebrate/cytology/physiology Lobsters Models, Neurological Motor Neurons/drug effects/*physiology Neural Inhibition Patch-Clamp Techniques Periodicity Potassium/physiology Pylorus/innervation/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologym@91. The lateral pyloric (LP) neuron is a component of the 14-neuron pyloric central pattern generator in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. In the pyloric rhythm, this neuron fires rhythmic bursts of action potentials whose phasing depends on the pattern of synaptic inhibition from other network neurons and on the intrinsic postinhibitory rebound properties of the LP cell itself. Bath-applied dopamine excites the LP cell and causes its activity to be phase advanced in the pyloric motor pattern. At least part of this modulatory effect is due to dopaminergic modulation of the intrinsic rate of postinhibitory rebound in the LP cell. 2. The LP neuron was isolated from all detectable synaptic input. We measured the rate of recovery after 1-s hyperpolarizing current injections of varying amplitudes, quantifying the latency to the first spike following the hyperpolarizing prepulse and the interval between the first and second action potentials. Dopamine reduced both the first spike latency and the first interspike interval (ISI) in the isolated LP neuron. During the hyperpolarizating pre-steps, the LP cell showed a slow depolarizing sag voltage that was enhanced by dopamine. 3. We used voltage clamp to analyze dopamine modulation of subthreshold ionic currents whose activity is affected by hyperpolarizing prepulses. Dopamine modulated the transient potassium current IA by reducing its maximal conductance and shifting its voltage dependence for activation and inactivation to more depolarized voltages. This outward current is normally transiently activated after hyperpolarization of the LP cell, and delays the rate of postinhibitory rebound; by reducing IA, dopamine thus accelerates the rate of rebound of the LP neuron. 4. Dopamine also modulated the hyperpolarization-activated inward current Ih by shifting its voltage dependence for activation 20 mV in the depolarizing direction and accelerating its rate of activation. This enhanced inward current helps accelerate the rate of rebound in the LP cell after inhibition. 5. The relative roles of Ih and IA in determining the first spike latency and first ISI were explored using pharmacological blockers of Ih (Cs+) and IA [4-aminopyridine (4-AP)]. Blockade of Ih prolonged the first spike latency and first ISI, but only slightly reduced the net effect of dopamine. In the continued presence of Cs+, blockade of IA with 4-AP greatly shortened the first spike latency and first ISI. Under conditions where both Ih and IA were blocked, dopamine had no additional effect on the LP cell. 6. We used the dynamic clamp technique to further study the relative roles of IA and Ih modulation in dopamine's phase advance of the LP cell. We blocked the endogenous Ih with Cs+ and replaced it with a simulated current generated by a computer model of Ih. The neuron with simulated Ih gave curves relating the hyperpolarizing prepulse amplitude to first spike latency that were the same as in the untreated cell. Changing the computer parameters of the simulated Ih to those induced by dopamine without changing IA caused only a slight reduction in first spike latency, which was approximately 20% of the total reduction caused by dopamine in an untreated cell. Bath application of dopamine in the presence of Cs+ and simulated Ih (with control parameters) allowed us to determine the effect of altering IA but not Ih: this caused a significant reduction in first spike latency, but it was still only approximately 70% of the effect of dopamine in the untreated cell. Finally, in the continued presence of dopamine, changing the parameters of the simulated Ih to those observed with dopamine reduced the first spike latency to that seen with dopamine in the untreated cell. 7. We generated a mathematical model of the lobster LP neuron, based on the model of Buchholtz et al. for the crab LP neuron.J Neurophysiol 19957441404-20d^Harris-Warrick, R.M. Baro, D.J. Coniglio, L.M. Johnson, B.R. Levini, R.M. Peck, J.H. Zhang, B. 1997RKChemical modulation of crustacean stomatogastric pattern generator networks >8Stein, P.S.G. Grillner, S. Selverston, A.I. Stuart, D.G.*#Neuron, Networks and Motor Behavior  Cambridge, MA+  MIT Press209-215XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9928309`YHarris-Warrick, R. M. Johnson, B. R. Peck, J. H. Kloppenburg, P. Ayali, A. Skarbinski, J. RLDistributed effects of dopamine modulation in the crustacean pyloric networkAnimal Crustacea Dopamine/*physiology Ganglia, Invertebrate/chemistry/cytology/physiology Motor Neurons/chemistry/*physiology Pylorus/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.tIt is now clear that neuromodulators can reconfigure a single motor network to allow the generation of a family of related movements. Using dopamine modulation of the 14-neuron pyloric network from the crustacean stomatogastric ganglion as an example, we describe two major mechanisms by which network output is modulated. First, the baseline electrophysiological properties of the network neurons can be altered. Dopamine can affect the activity of each neuron independently. For example, DA modulates IA in nearly every neuron in the pyloric network, but in opposite directions in different cells. Furthermore, DA usually modulates combinations of ionic currents. In some cases, currents with opposing actions on cell excitability are simultaneously affected, and the net response reflects the sum of these opposing effects. Second, neuromodulators can alter the strength of synaptic interactions within the network, quantitatively "rewiring" the network. Every synapse in the network is affected by DA, with some increased and others decreased in strength. DA acts both pre- and postsynaptically to affect transmission: these actions are frequently opposing in sign, and the net response arises as the sum of these opposing actions. Finally, spike-evoked and graded transmission at the same synapse can be oppositely affected by DA. These results emphasize the distributed nature of modulation in motor networks.n'ngSection of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA. rmh4@cornell.edue9928309Ann N Y Acad Sci 1998 860155-67.12490254126A 2002 Dec0>8Voltage-sensitive ion channels in rhythmic motor systems 646-51Voltage-sensitive ionic currents shape both the firing properties of neurons and their synaptic integration within neural networks that drive rhythmic motor patterns. Persistent sodium currents underlie rhythmic bursting in respiratory neurons. H-type pacemaker currents can act as leak conductances in spinal motoneurons, and also control long-term modulation of synaptic release at the crayfish neuromuscular junction. Calcium currents travel in rostro-caudal waves with motoneuron activity in the spinal cord. Potassium currents control spike width and burst duration in many rhythmic motor systems. We are beginning to identify the genes that underlie these currents.'tnDepartment of Neurobiology and Behavior, Seeley G. Mudd Hall, Cornell University, 14853, Ithaca, New York, USAHarris-Warrick, R. M.("22378506 0959-4388 Journal ArticleCurr Opin Neurobiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12490254sis of Variance Animal9435160360Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.|vDifferential modulation of chemical and electrical components of mixed synapses in the lobster stomatogastric ganglionxqAnimal Biogenic Amines/*pharmacology Dopamine/pharmacology Electrophysiology Ganglia, Invertebrate/*physiology Lobsters/*physiology Neural Inhibition/drug effects Neuronal Plasticity Octopamine/pharmacology Pylorus/*innervation Serotonin/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*drug effects/*physiologya 1. Two pairs of neurons in the pyloric network of the spiny lobster, Panulirus interruptus, communicate through mixed graded chemical and rectifying electrical synapses. The anterior burster (AB) chemically inhibits and is electrically coupled to the ventricular dilator (VD); the lateral pyloric (LP) and pyloric (PY) neurons show reciprocal chemical inhibition and electrical coupling. We examined the effects of dopamine (DA), serotonin (5HT) and octopamine (Oct) on these mixed synapses to determine the plasticity possible with opposing modes of synaptic interaction. 2. Dopamine increased net inhibition at all three pyloric mixed synapses by both reducing electrical coupling and increasing chemical inhibition. This reversed the sign of the net synaptic interaction when electrotonic coupling dominated some mixed synapses, and activated silent chemical components of other mixed synapses. 3. Serotonin weakly enhanced LP-->PY net inhibition, by reducing electrical coupling without altering chemical inhibition. Serotonin reduced AB-->VD electrical coupling, but variability in its effect on the chemical component made the net effect non-significant. 4. Octopamine enhanced LP-->PY and PY-->LP net inhibition by enhancing the chemical inhibitory component without altering electrical coupling. 5. Differential modulation of chemical and electrical components of mixed synapses markedly changes the net synaptic interactions. This contributes to the flexible outputs that modulators evoke from anatomically defined neural networks.J Comp Physiol [A] 1994 1752 233-49 :4 80043197("Hartline, D. K. Gassie, D. V., Jr.{Pattern generation in the lobster (Panulirus) stomatogastric ganglion. I. Pyloric neuron kinetics and synaptic interactionsAdaptation, Physiological Animal Ganglia/*physiology Kinetics Lobsters Membrane Potentials Models, Neurological Nerve Net/physiology Neurons/*physiology Periodicity Pylorus/*innervation Stomach/innervation Support, U.S. Gov't, P.H.S. Synapses/*physiologyThere are a number of perspectives gained from a quantitative analysis of the pyloric system which may be applicable to other simple pattern generators: 1. The system is organized around a dominant, endogenously- bursting neuron group, and its properties are tailored to that dominance. In particular, synaptic strengths and firing frequencies of that group appear just sufficient to suppress postsynaptic "follower" cells if the latter are not too highly excited. 2. Repetitive firing properties of follower neurons are such as to facilitate their switch- like mode of activity. This includes pacemaker response nonlinearities, rebound properties, and "burstiness" properties. 3. Proper sequencing of follower cells may be controlled by particular synaptic strengths and time-courses, feedback on the oscillator cells, and functional cellular properties of follower neurons (e.g., rebound; see also next paper). All such properties interact and must be tuned to each other for proper patterns to result. Biol Cybern 1979334 209-2285056950$Hartline, D. K. Russell, D. F.~xEndogenous burst capability in a neuron of the gastric mill pattern generator of the spiny lobster Panulirus interruptuspiAnimal Electrophysiology Female Ganglia/*physiology Lobsters Male Periodicity Support, U.S. Gov't, P.H.S.i D >The gastric system of the lobster stomatogastric ganglion has previously been thought to include no neurons capable of endogenous bursting. We describe conditions under which one of the motorneurons, the CP cell, can burst endogenously in a free-running manner in the absence of other phasic network activity. Isolated preparations of the foregut nervous system were used, and the CP bursting was either spontaneous or was activated by continuous stimulation of an input nerve. Three criteria were applied to establish the endogenous nature of such burst generation in CP: absence of phasic input, reset of the bursting pattern by pulses of current in a characteristic phase- dependent manner, and modulation of burst rate by sustained injected current. (1) The firing of other cells which are known to be related synaptically to CP was monitored in nerve records. These other cells were either silent or fired only tonically. Cross-correlograms showed that CP bursting was not ascribable to phasic activity in these other network cells. (2) A depolarizing current pulse of sufficient strength injected intracellularly between bursts triggered a burst prematurely and reset the subsequent rhythm. A hyperpolarizing pulse during a burst terminated it and reset the subsequent rhythm. Reset behavior was similar to that described for other endogenous bursters. (3) Application of a positive-going ramp current initially caused an increase in burst rate, as described for other endogenous bursters. However, further depolarization caused a slower burst rate due to lengthening of the individual bursts, although mean firing frequency continued to increase throughout the range tested. Such free-running endogenous repetitive bursting appeared to result from the CP's ability to produce slow regenerative depolarizations ("plateau potentials"). When bursting was present, so was the plateau property, as determined by I-V analysis and by the ability of brief current pulses to trigger and terminate bursts. The previous inability to observe endogenous bursting in preparations with central input removed may be due to the usual absence of the plateau property in such preparations. CP bursting during normal gastric mill rhythms, while underlain by plateau potentials, is strongly controlled by network interactions. CP appears not to be well placed in the network to be considered a source of normal gastric rhythmicity. Nevertheless, endogenous bursting in CP may explain some of the partial gastric rhythms seen in behavioral studies, and illustrates one way that cellular properties might contribute to rhythmic behaviors. J Neurobiol 1984155 345-64Hartline, D.K. 1987& Modeling stomatogastric ganglion "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag181-197Hartline, D.K. 1987Plateau potential  Adelman, G."Encyclopedia of Neuroscience Boston  Birkhauser955-9560)Hartline, D.K. Gassie, D.V. Sirchia, C.D.a 1987j9PY cell types in the stomatogastric ganglion of Panulirus 0 "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-VerlagThe Crustacean 75-7789090479>8Hartline, D. K. Russell, D. F. Raper, J. A. Graubard, K.JDSpecial cellular and synaptic mechanisms in motor pattern generationAnimal Crustacea/*physiology Motor Neurons/cytology/*physiology Support, U.S. Gov't, P.H.S. Synapses/*physiology Synaptic Transmission 1988Comp Biochem Physiol C9114 115-31 Using Smart Source ParsingHartline, D.K. 1989JDSimulation of restricted neural networks with reprogrammable neurons"IEEE Trans Circuits Systems36653-660Hartline, D.K. 1991JCThe neuron as a reprogrammable computing element in neural networks  Fraser, M.ZSAdvances in Control Networks and Large Scale Parallel Distributed Processing Models  Norwood, NJ Ablex 58-82"Hartline, D.K. Graubard, K. 1992VPCellular and synaptic properties in the crustacean stomatogastric nervous system BDymanic Biological Networks: The Stomatogastric Nervous System  Cambridge, MA  MIT Press 31-86&87011461NHHooper, S. L. O'Neil, M. B. Wagner, R. Ewer, J. Golowasch, J. Marder, E.The innervation of the pyloric region of the crab, Cancer borealis: homologous muscles in decapod species are differently innervatedAcetylcholine/pharmacology Crabs Curare/pharmacology Electric Conductivity Electric Stimulation Ganglia/physiology Glutamates/pharmacology Motor Neurons/drug effects/*physiology Muscles/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.piThe muscles of the pyloric region of the stomach of the crab, Cancer borealis, are innervated by motorneurons found in the stomatogastric ganglion (STG). Electrophysiological recording and stimulating techniques were used to study the detailed pattern of innervation of the pyloric region muscles. Although there are two Pyloric Dilator (PD) motorneurons in lobsters, previous work reported four PD motorneurons in the crab STG (Dando et al. 1974; Hermann 1979a, b). We now find that only two of the crab PD neurons innervate muscles homologous to those innervated by the PD neurons in the lobster, Panulirus interruptus. The remaining two PD neurons innervate muscles that are innervated by pyloric (PY) neurons in P. interruptus. The innervation patterns of the Lateral Pyloric (LP), Ventricular Dilator (VD), Inferior Cardiac (IC), and PY neurons were also determined and compared with those previously reported in lobsters. Responses of the muscles of the pyloric region to the neurotransmitters, acetylcholine (ACh) and glutamate, were determined by application of exogenous cholinergic agonists and glutamate. The effect of the cholinergic antagonist, curare, on the amplitude of the excitatory junctional potentials (EJPs) evoked by stimulation of the pyloric motor nerves was measured. These experiments suggest that the differences in innervation pattern of the pyloric muscles seen in crab and lobsters are also associated with a change in the neurotransmitter active on these muscles. Possible implications of these findings for phylogenetic relations of decapod crustaceans and for the evolution of neural circuits are discussed.J Comp Physiol [A] 1986 1592 227-4087282571Hooper, S. L. Marder, E.HAModulation of the lobster pyloric rhythm by the peptide proctolin(!Action Potentials Animal Digestive System/innervation Female Ganglia/physiology Interneurons/drug effects/physiology Lobsters/*physiology Male Motor Neurons/*physiology Nervous System/drug effects/*physiology *Nervous System Physiology Oligopeptides/*physiology Support, U.S. Gov't, P.H.S.hPJThe modulation of the pyloric network of the stomatogastric ganglion (STG) of the lobster Panulirus interruptus by the neuropeptide proctolin is described. First, the effects of proctolin on the pyloric motor patterns were characterized in terms of frequency and phase relations. Pyloric cycle frequency and lateral pyloric (LP) neuron activity increased and ventricular dilator (VD) neuron activity decreased with increasing concentrations (10(-9)-10(-6) M) of applied proctolin. Next, the effects of proctolin on the individual neurons that constitute the pyloric network were determined. Identified neurons were isolated from chemical and electrical presynaptic inputs by using pharmacological agents (Marder and Eisen, 1984a) and/or photoinactivation following Lucifer yellow injection (Miller and Selverston, 1979). Proctolin increased the amplitude and frequency of bursts produced by isolated pacemaker anterior burster (AB) neurons. Isolated LP and pyloric (PY) neurons responded to proctolin with increases in activity only when they were at or above threshold. All other pyloric neurons were unaffected. To determine how the direct effects of proctolin on isolated neurons resulted in the observed changes in frequency and phase relations in the motor pattern of the intact pyloric circuit seen in proctolin, individual neurons were deleted from the circuit. A comparison of proctolin's effects on isolated neurons with those on the intact network shows that the synaptic connectivity among neurons directly affected by proctolin and those unaffected by it shapes the network's response to proctolin. J Neurosci 19877d7o2097-11289298390 Hooper, S. L. Moulins, M.cjcSwitching of a neuron from one network to another by sensory-induced changes in membrane properties82Action Potentials Animal Cell Membrane/physiology Electric Stimulation Lobsters/*physiology Membrane Potentials Nervous System/cytology/*physiology *Nervous System Physiology Neural Pathways/cytology/physiology Neurons/*physiology Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.A neuron that is an integral member of the pyloric neural network of the lobster stomatogastric nervous system leaves this network and instead fires exclusively with another stomatogastric nervous system network, the cardiac sac network, whenever the cardiac sac network is active. This switch is associated with the neuron losing, in a long- lasting fashion, regenerative oscillatory membrane properties that underlie its participation in the pyloric network. Functional membership of neurons in central networks is thus not fixed, and long- lasting neuromodulatory influences, controlled at least in part by sensory inputs, can switch neurons from one network to another.Science 1989 244 4912 1587-9 ". 933532410*Hartline, D. K. Gassie, D. V. Jones, B. R.~xEffects of soma isolation on outward currents measured under voltage clamp in spiny lobster stomatogastric motor neurons~Animal Calcium/physiology Computer Simulation Electrophysiology Female Ganglia/cytology/physiology In Vitro Ion Channels/*physiology Kinetics Lobsters/*physiology Male Membrane Potentials/physiology Microelectrodes Models, Neurological Motor Neurons/*physiology Neurites/physiology Pylorus/innervation Stomach/*innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.F?1. Outward currents in identified cell types from the pyloric system of the stomatogastric ganglion (STG) of the spiny lobster, Panulirus marginatus, were studied under two-microelectrode voltage clamp. A comparison was made between data from intact cells and somata isolated by ligation of the primary neurite of these monopolar neurons. 2. Despite the elimination of current contributions from the extensive arborizations of STG neurons, few significant differences were found in the mean values of parameters for outward currents between populations of isolated somata and intact cells of a given type. Measurements that showed little difference included magnitude and activation threshold of a calcium-dependent outward current (IJ) and magnitude, activation threshold, voltage dependence, and inactivation time course of A current (IA). Although previous work has suggested that IJ might reside predominantly in the soma, IA is known to be distributed in poorly space-clamped neurite processes. The absence of obvious effects of isolation was thus unexpected. 3. To better understand the mechanisms involved, we used compartmental models derived from reconstructed neurons to simulate the effects of isolation. It was concluded that, for the particular conditions present in stomatogastric neurons, with a large, uniformly distributed outward current conductance activated, even though neurites and axon remain attached, most measured current flows through well-clamped soma membrane. 4. Factors contributing to this result included the outward sign of the current, the large specific conductance activated in these neurons (among the larger reported in somata), and the presence of only a single major process leaving the soma. The potential for serious errors in voltage-clamp measurements from intact cells remains if these conditions are not met.J Neurophysiol 19936962056-7112766427143w 2003May-JunrztSimulations of voltage clamping poorly space-clamped voltage-dependent conductances in a uniform cylindrical neurite 253-69Significant error is made by using a point voltage clamp to measure active ionic current properties in poorly space-clamped cells. This can even occur when there are no obvious signs of poor spatial control. We evaluated this error for experiments that employ an isochronal I(V) approach to analyzing clamp currents. Simulated voltage clamp experiments were run on a model neuron having a uniform distribution of a single voltage-gated inactivating ionic current channel along an elongate, but electrotonically compact, process. Isochronal Boltzmann I(V) and kinetic parameter values obtained by fitting the Hodgkin-Huxley equations to the clamp currents were compared with the values originally set in the model. Good fits were obtained for both inward and outward currents for moderate channel densities. Most parameter errors increased with conductance density. The activation rate parameters were more sensitive to poor space clamp than the I(V) parameters. Large errors can occur despite "normal"-looking clamp curves.i'Bekesy Laboratory of Neurobiology, Pacific Biomedical Research Center, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI 96822.*#Hartline, D. K. Castelfranco, A. M.("22651244 0929-5313 Journal ArticleJ Comput Neuroscilehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12766427DHeinzel, H. G. 1987{Appendix B: Spontaneous and proctolin-induced modes of operation of the isolated gastric oscillator and of the gastric mill "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag 175-180&Heinzel, H. G. Selverston, A.I. 1987LFReset analysis of the gastric central pattern generator in the lobster Elsner, N. Creutzfeldt, O..(New Frontiers in Crustacean Neurobiology New York Thieme Stuttgart67Heinzel, H. G. 1988xGSensory control of the stomatogastric system in the crab Cancer pagurus\9 Elsner, N. Barth, G.@9Sense Organs, Interfaces Between Environment and Behaviora New York Thieme Stuttgart 82-11588171656Heinzel, H. G.LEGastric mill activity in the lobster. I. Spontaneous modes of chewingtAnimal Biomechanics *Dentition Lobsters/*physiology Male *Mastication Muscles/physiology Reflex/physiology Stomach/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Time Factorsh|v1. The gastric central pattern generator (CPG) driving the three teeth of the gastric mill inside the lobster stomach has often been used as a model for the study of central nervous systems, but the actual functioning of the mill has never been observed directly. By using a small endoscope inserted through the esophagus a video analysis of the tooth movements was performed with restrained, but otherwise intact lobsters. 2. The teeth show spontaneous periodic chewing (cycle duration from 4 to 70 s) in two different basic modes. In the squeeze mode only the cusps of the three teeth move together simultaneously. In the cut-and-grind mode the lateral teeth close first with not only their cusps, but also their serrated edges. After this cut phase the lateral teeth grind backward along the file of the medial tooth, which simultaneously moves forward. 3. Simultaneous endoscope recordings of the teeth, filming of stomach muscles and ossicles combined with electrical stimulation of selected muscles reveal that muscle gm3c is responsible for this hitherto unknown backward grinding of the lateral teeth. 4. The complete behavioral repertoire includes the following modifications of the two basic modes. 1) The lateral teeth can perform chewing movements while the medial tooth stays still and vice versa, forms of chewing regarded even weaker than the squeeze. 2) There do not appear to be intermediates between the squeeze and cut-and-grind movements, with the latter as the strongest form of chewing. Transitions only occur as switching on a cycle-by-cycle basis. 3) A gradual change of the cut-and-grind chewing was observed as the gradual development of an additional opening over the time course of several periods. 4) After their grind phase, the lateral teeth can even move further back beyond the medial tooth. This can serve to push food into the pyloric filter apparatus. 5. Inflation of the cardiac sac can elicit single bites in a resting gastric mill. 6. The behavioral repertoire is compared with the in vivo activity of the gastric oscillator represented by simultaneous intracellular recording from 7 representative cells of the 11 CPG neurons.J Neurophysiol 1988592 528-50$HAHemple, C.M. Vincent, P. Adams, S.R. Tsien, R.Y. Selverston, A.I. 1996PJSpatio-temporal dynamics of cyclic AMP signals in an intact neural circuit Nature 384166-169Hermann, A. Dando, M.R. 1977Mechanisms of command fibre operation onto butsting pacemaker neurons in the stomatogastric ganglion of the crab, Cancer pagurusrJ Comp Physiol 114 15-33p Hermann, A. 1979Generation of a fixed motor pattern. I. Details of synaptic interconnections of pyloric neurons in the stomatogastric ganglion of the crab, Cancer pagurusJ Comp Physiol 130221-228 Hermann, A. 1979Generation of a fixed motor pattern. II. Electrical properties and synaptic characteristics of pyloric neurons in the stomatogastric ganglion of the crab, Cancer pagurusJ Comp Physiol 130229-23982026425 Hermann, A. ZTAction of caffeine on pyloric motorneurons in the crustacean stomatogastric ganglionAction Potentials/drug effects Animal Caffeine/*pharmacology Crabs/*physiology Crayfish/*physiology Ganglia/*drug effects Membrane Potentials/drug effects Motor Neurons/*drug effects Ouabain/pharmacology Pylorus/cytology/drug effects  1981Comp Biochem Physiol C692P 191-7l Using Smart Source ParsingHermann, A. Wadepuhl, M. 1987B;Ionic basis of pacemaker activity in stomatogastric neurons "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag101-107PHinton, D.J. Corey, S. 1979~MThe mouthparts and digestive tract in the larval stages of Homarus americanus; Can J Zool57 1413-1423i84258552Hooper, S. L. Marder, E.^WModulation of a central pattern generator by two neuropeptides, proctolin and FMRFamide Animal Comparative Study Crabs/*physiology Ganglia/*drug effects/metabolism In Vitro Motor Neurons/drug effects Neurotransmitters/*pharmacology Oligopeptides/metabolism/*pharmacology Stimulation, Chemical Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The neuropeptides, proctolin and FMRFamide, increase the frequency of, and modify the motor pattern produced by, the stomatogastric ganglion (STG) of the crab, Cancer irroratus. Both proctolin-like and FMRFamide- like immunoreactivities are present in fibers in the stomatogastric nerve which terminate in the neuropile of the STG. The neural output of the STG thus appears to be modulated by at least two different groups of peptidergic input fibers.) Brain Resd 1984 305o1n 186-91,s/*metabolism Animal9226042260Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.ztElevated temperature alters the ionic dependence of amine-induced pacemaker activity in a conditional burster neuronleAnimal Biogenic Amines/*physiology Biological Clocks/*physiology Calcium/metabolism Dopamine/physiology Heat In Vitro Lobsters/*physiology Magnesium/metabolism Membrane Potentials/physiology Neurons/*physiology Octopamine/physiology Serotonin/physiology Sodium/metabolism Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetrodotoxin/pharmacologyJThe anterior burster neuron of the lobster (Panulirus interruptus) stomatogastric ganglion is a conditional burster that functions as the primary pacemaker for the pyloric motor network. When modulatory inputs to this cell are blocked, it loses its bursting properties and becomes quiescent. Applications of the monoamines, dopamine, octopamine or serotonin restore rhythmic bursting in this cell (Flamm and Harris- Warrick 1986). At 15 degrees C, serotonin- and octopamine-induced oscillations depend critically upon sodium entry (blocked by low sodium saline or tetrodotoxin); dopamine-induced oscillations depend upon calcium entry (blocked by reduced extracellular calcium; Harris-Warrick and Flamm 1987). We show here that the ionic dependence of amine- induced oscillations in the anterior burster cell differs at 15 and 21 degrees C. At 21 degrees C, all amines have the potential to induce rhythmic oscillations in saline containing tetrodotoxin. At the elevated temperature and in tetrodotoxin, both calcium and sodium currents are essential for the maintenance of dopamine-induced oscillations; serotonin-induced oscillations do not depend upon either calcium or sodium alone; octopamine-induced oscillations do not depend upon calcium and show a variable dependence upon sodium. Thus, multiple ionic mechanisms, which vary with both the modulator and the ambient temperature, can be recruited to support rhythmic activity in a conditional burster neuron.eJ Comp Physiol [A] 1992 170 2d 201-9t> t 688171657Heinzel, H. G.f`Gastric mill activity in the lobster. II. Proctolin and octopamine initiate and modulate chewing& Animal *Dentition Dose-Response Relationship, Drug Injections Lobsters/*physiology *Mastication/drug effects Octopamine/pharmacology/*physiology Oligopeptides/pharmacology/*physiology Reflex/drug effects Stomach/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Time FactorsLE1. The neuromodulators proctolin and octopamine were injected into the circulatory system of lobsters, and the subsequent reaction of their gastric mill was analyzed with the help of an endoscope. 2. Injections of proctolin into the dorsal heart sinus elicited chewing with period durations of 5-60 s after a latency of 53 +/- 42 s (n = 32 injections). The threshold dose was 1 ml of 1.5 X 10(-7) M, which results in an estimated concentration of 3 X 10(-9) M in the blood. 3. The effects of proctolin on the coordination of the three teeth of the gastric mill is dose dependent. Proctolin injections of 1 ml of 1.5 X 10(-6) M elicited chewing in the squeeze mode, 1 ml of 1.5 X 10(-4) M triggered chewing in the cut-and-grind mode. Both modes are different in terms of coordination and usage of functionally different parts of the teeth. 4. An increase in the proctolin dose causes an increase of the duty cycle (ratio of closing duration to period duration) of the chewing from 0.19 to 0.51. The corresponding period duration shortens (from 30.8 to 9.9 s) at intermediate doses, but lengthens to 16.6 s at high doses because the closing duration goes up. 5. Chewing following a single injection can last between 2 and 30 min. Besides more or less stereotypic chewing in one of the basic modes, variations occurred, such as chewing of just the lateral teeth, cycle-by-cycle switching between different modes, or double bites of either the lateral teeth or the medial tooth. 6. Proctolin increased the strength of reflex bites, which could be elicited by mechanical stimulation of the cardiac sac. 7. Octopamine elicited not only irregular chewing, but also other reactions such as struggling, only if high doses, between 1 ml of 1.5 X 10(-4) and 1.5 X 10(-3) M were given, which correspond to an estimated concentration in the blood of between 3 X 10(-6) and 3 X 10(-5) M. 8. The proctolin effects on the gastric mill match the spontaneously occurring behavioral repertoire of the gastric mill, and they are explainable with known properties of the gastric central pattern generator and its sensitivity to proctolin.J Neurophysiol 1988592 551-6588171658& Heinzel, H. G. Selverston, A. I.piGastric mill activity in the lobster. III. Effects of proctolin on the isolated central pattern generatorVPAnimal *Dentition Dose-Response Relationship, Drug Ganglia/cytology/*drug effects/physiology In Vitro Lobsters/*physiology Motor Neurons/drug effects/physiology Nerve Block Nervous System/physiology Nervous System Physiology Oligopeptides/*pharmacology Stomach/innervation/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. > 81. The response of the isolated gastric central pattern generator (CPG) to bath application of proctolin is characterized and compared with the previously analyzed behavioral response. 2. Proctolin had an excitatory effect on the ongoing spontaneous rhythm of "combined" preparations, in which the stomatogastric ganglion (STG) is connected to the esophageal and commissural ganglia by the stomatogastric nerve (STN). The effect started between 20 s and 5 min and was characterized by strongly increased burst durations as well as increased spike rates in all units except the two lateral posterior gastric (LPG) motoneurons. The effect was strongest in the dorsal gastric (DG) and lateral gastric (LG) motoneurons and was accompanied by a phase change of the DG burst. DG continued spiking throughout large parts of the burst of LG and of the gastric mill (GM) motoneurons, which are antagonists of DG. 3. The threshold concentration was approximately 10(-10) M, and the effects were dose dependent and reversible. 4. LG and DG were identified as target cells for the action of proctolin. In LG regenerative plateau properties were induced, as revealed by its long-lasting plateau potentials, sensitivity for triggering inputs, and the occurrence of oscillatory prepotentials. An induction of endogenous bursting in DG was concluded from preparations, in which DG was cycling alone or bursting with a much shorter period duration than other gastric neurons. Hyperpolarization of DG, which normally has no or weak driving power within the gastric network, demonstrated that under the influence of proctolin, firing of DG can accelerate the gastric rhythm from a 27- to a 9-s period duration. 5. Proctolin does not only have a modulatory influence on an ongoing rhythm, but it also can trigger gastric activity. This function was first concluded from proctolin-treated STGs, which, unlike normal preparations, continue bursting if inputs via the STN are blocked. Finally, triggering was demonstrated directly, since isolated STGs that were not oscillating started a gastric rhythm after 20-30 min of perfusion with proctolin. 6. The proctolin-induced changes of the CPG activity in isolated preparations are in agreement with the effect on gastric mill chewing in the intact animal, in which, depending on the dose, different modes of chewing could be elicited.J Neurophysiol 1988592 566-85Heinzel, H. G. 1990^The cooperation of several oscillators in the stomatogastric system of the crab Cancer pagurusP @:Wiese, K. Krenz, W.-D. Tautz, J. Reichert, H. Mulloney, B.*$Frontiers in Crustacean Neurobiology Basel Verlag455-462+Heinzel, H. G. 1990D=Modulation and sensory control of the crustacean gastric mill3 0)Erber, J. Menzel, R. Pfluger, H. Todt, D.r$Neural Mechanisms of Behavior  Stuttgart Georg Thieme Verlag_ 61-66_*$Heinzel, H. G. Bohm, H. Weigeldt, D. 1993^XThe cooperation of neural nerworks as the basis for the plasticity of rhythmic movementsVerh Dtsch Zool Ges86165-17693217558.(Heinzel, H. G. Weimann, J. M. Marder, E.The behavioral repertoire of the gastric mill in the crab, Cancer pagurus: an in situ endoscopic and electrophysiological examination 60Animal Behavior, Animal/physiology Comparative Study *Digestive Physiology Digestive System/innervation/*physiology Electrophysiology Female Ganglia/cytology/physiology Gastroscopy Male Neurons/physiology Periodicity Pylorus/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Tooth/physiologySimultaneous endoscopic and electrophysiological recordings were used to observe the behavior of the gastric mill complex while recording the motor output of the stomatogastric ganglion (STG) in intact crabs. In the crab STG, many pattern-generating neurons are able to fire in several distinct rhythmic motor patterns. Specifically, many neurons can switch between firing in time with the rapid pyloric rhythm to firing in time with the slower gastric mill rhythm (Weimann et al., 1991). We now correlate behaviorally relevant movements of the gastric mill with some of the modifications of neuronal firing patterns previously characterized using in vitro STG preparations. The intracellular and extracellular recordings from the intact crab are largely indistinguishable from those obtained from in vitro preparations. For the first time, we describe the movements that result as neurons switch their activity patterns associated with activation of the gastric mill rhythm. Extracellular stimulation and intracellular depolarization of individual motor neurons is used to determine the relationship between frequency of firing and movement in behaving animals. J Neurosci 1993134o1793-803 1500442313 1-2n 2004Jan-Apr PIThe insect frontal ganglion and stomatogastric pattern generator networksl 20-36aInsect neural networks have been widely and successfully employed as model systems in the study of the neural basis of behavior. The insect frontal ganglion is a principal part of the stomatogastric nervous system and is found in most insect orders. The frontal ganglion constitutes a major source of innervation to foregut muscles and plays a key role in the control of foregut movements. Following a brief description of the anatomy and development of the system in different insect groups, this review presents the current knowledge of the way neural networks in the insect frontal ganglion generate and control behavior. The frontal ganglion is instrumental in two distinct and fundamental insect behaviors: feeding and molting. Central pattern-generating circuit(s) within the frontal ganglion generates foregut rhythmic motor patterns. The frontal ganglion networks can be modulated in-vitro by several neuromodulators to generate a variety of motor outputs. Chemical modulation as well as sensory input from the gut and input from other neural centers enable the frontal ganglion to induce foregut rhythmic patterns under different physiological conditions. Frontal ganglion neurons themselves are also an important source of neurosecretion. The neurosecretory material from the frontal ganglion can control and modulate motor patterns of muscles of the alimentary canal. The current and potential future importance of the insect stomatogastric nervous system and frontal ganglion in the study of the neural mechanisms of behavior are discussed.'rlDepartment of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. ayali@post.tau.ac.il Ayali, A. & 1424-862x Journal Article Review Neurosignals2+Animals Behavior, Animal Digestive System/innervation/metabolism Electric Stimulation Feeding Behavior/physiology Ganglia, Invertebrate/anatomy & histology/*physiology Insects Molting/physiology Nerve Net/cytology/*physiology *Nervous System Physiology *Neural Networks (Computer) Neurons/physiology lehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15004423AM V151753832422 2004 Jun 2e|Dynamic interaction of oscillatory neurons coupled with reciprocally inhibitory synapses acts to stabilize the rhythm period5140-50dnhIn the rhythmically active pyloric circuit of the spiny lobster, the pyloric dilator (PD) neurons are members of the pacemaker group of neurons that make inhibitory synapses onto the follower lateral pyloric (LP) neuron. The LP neuron, in turn, makes a depressing inhibitory synapse to the PD neurons, providing the sole inhibitory feedback from the pyloric network to its pacemakers. This study investigates the dynamic interaction between the pyloric cycle period, the two types of neurons, and the feedback synapse in biologically realistic conditions. When the rhythm period was changed, the membrane potential waveform of the LP neuron was affected with a consistent pattern. These changes in the LP neuron waveform directly affected the dynamics of the LP to PD synapse and caused the postsynaptic potential (PSP) in the PD neurons to both peak earlier in phase and become larger in amplitude. Using an artificial synapse implemented in dynamic clamp, we show that when the LP to PD PSP occurred early in phase, it acted to speed up the pyloric rhythm, and larger PSPs also strengthened this trend. Together, these results indicate that interactions between these two types of neurons can dynamically change in response to increases in the rhythm period, and this dynamic change provides a negative feedback to the pacemaker group that could work to stabilize the rhythm period.'jdCenter for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA.Mamiya, A. Nadim, F. 1529-2401 Journal Articlee J Neurosci:3Animals Biological Clocks/*physiology Digestive System/innervation Excitatory Postsynaptic Potentials/physiology Feedback/physiology In Vitro Models, Neurological Neural Inhibition/*physiology Neurons/*physiology Palinuridae/*physiology *Periodicity Research Support, U.S. Gov't, P.H.S. Synapses/*physiologyLlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15175383o84164080("Mancillas, J. R. Selverston, A. I.Neuropeptide modulation of photosensitivity. II. Physiological and anatomical effects of substance P on the lateral eye of LimulusAnimal Arousal/physiology Circadian Rhythm/drug effects Dose-Response Relationship, Drug Electroretinography Eye/anatomy & histology/innervation/*physiology Female Horseshoe Crabs/*physiology *Light Male Photoreceptors/drug effects/radiation effects Substance P/*pharmacologyhF@A system of efferent substance P-like immunoreactive fibers innervates the ommatidia of the Limulus lateral eye. Thus, we tested the physiological effects of substance P on the lateral eye by measuring the electroretinogram, a population potential reflecting the photoreceptors' response to light, under different experimental conditions. Substance P had no direct effect on the photoreceptors, but it induced an increase in their responsiveness to test flashes of light. The latency, magnitude, and duration of this reversible modulatory effect was dose-dependent. The lateral eye displays an endogenous circadian rhythm in its responsiveness to light. Application of exogenous substance P in the daytime causes an immediate rise as well as an increase in the nocturnal peak, while injection of one of its antagonists (D-Pro2, D-Phe7, D-Trp9 substance P) in the afternoon retards the normal rise in sensitivity and reduces the nighttime levels. Passive incubation with substance P antibodies at midnight caused a drop to diurnal levels of photosensitivity. Short-term changes in photosensitivity, similar in their nature to the substance P-induced ones, were caused by arousing the subjects. Arousal had an effect on the ongoing circadian rhythm similar to that of substance P application. Thus, the substance P efferent system may regulate neural responsiveness in both a short-term, environmentally induced manner, as well as for level setting in a circadian fashion. The mechanism for substance P-induced increases in photosensitivity involves changes in ommatidial structure: contraction of distal pigment cells, resulting in an increased aperture, and contraction of the retinular cells and rhabdom, resulting in a wider diameter of the latter. These structural modifications result in a greater angle of acceptance and increased light quantum catch. J Neurosci 198443 847-59> 91132254 Hooper, S. L. Moulins, M.arlCellular and synaptic mechanisms responsible for a long-lasting restructuring of the lobster pyloric network$Animal Electric Stimulation Electrophysiology Heart/innervation Isoquinolines/diagnostic use Lobsters/*physiology Neurons, Afferent/*physiology Pylorus/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Synapses/drug effects/physiology Synaptic Transmission/physiology  1. In the lobster Palinurus vulgaris a sensory input in the lateral posterolateral nerve (lpln) of the stomatogastric nervous system (STS) is able to turn on the cardiac sac (CS) network and to induce dramatic long-lasting alterations in the output of the pyloric network. This long-lasting alteration of pyloric network output consists primarily of changes in the activity of the two neurons that innervate the muscles of the cardiopyloric valve of the stomach, with the dilator neuron (the ventricular dilator, VD) transferring from the pyloric network to the CS network and the constrictor neuron (the inferior cardiac, IC) shifting to fire earlier in the pyloric pattern. 2. The inferior ventricular (IV) neurons of the CS network make complex multiaction synaptic connections onto several pyloric neurons in a related species, Panulirus interruptus. We show that many of the short-term alterations in pyloric activity observed during CS network bursts in Palinurus are due to similar IV neuron synaptic connections. However, the long- lasting effects of lpln stimulation on pyloric output are not due to this synaptic input, because 1) direct activation of the IV neurons does not induce long-lasting changes in pyloric activity and 2) pharmacologic disconnection of this synaptic input does not abolish lpln stimulation's long-lasting effects. Lpln stimulation therefore activates two different neuronal inputs to the pyloric network. 3. The transfer of the VD neuron from the pyloric to the CS network is the result of the concerted actions of these two inputs. Lpln stimulation turns on the CS network, and the IV neurons of the CS network excite the VD neuron and ensure it fires with the CS network. The second neuronal input (that not involving known CS network neurons) abolishes in a long-lasting fashion the VD neuron regenerative (plateau) properties, and thus suppresses the ability of the VD neuron to participate in the pyloric rhythmic pattern between CS network bursts. 4. Experimental manipulation of VD neuron activity can both mimic and reverse the effects of lpln stimulation on the IC neuron. The changes in IC neuron activity are therefore not due to direct lpln-activated synaptic input onto the IC neuron, but instead are indirect "network" effects arising from the changes in VD neuron activity.J Neurophysiol 19906451574-8991132253,&Hooper, S. L. Moulins, M. Nonnotte, L.^WSensory input induces long-lasting changes in the output of the lobster pyloric networktAnimal Electric Stimulation Electrophysiology Female Lobsters/*physiology Male Microscopy, Electron Neurons, Afferent/*physiology/ultrastructure Physical Stimulation Pylorus/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.1. A long-lasting restructuring of the pyloric neural network of the lobster stomatogastric nervous system (STS) by a multisynaptic sensory afferent is described. This restructuring can be obtained either by mechanical stimulation of the pyloric region of the stomach or by brief high-frequency electrical stimulation of a nerve that innervates this region, the lateral posterolateral nerve (lpln). Electron microscopy shows that this nerve contains several thousand very small fibers (approximately 0.3 microns diam), the activation of some subset of which is responsible for the effects of lpln stimulation. 2. These stimulation paradigms result in both short-duration changes in pyloric activity and modulatory effects long outlasting the stimulus end. The long-lasting changes include the cessation of rhythmic ventricular dilator (VD) and lateral pyloric (LP) neuron activity, and thus result in a reduced pyloric pattern in which only the pyloric dilator (PD), inferior cardiac (IC), anterior burster (AB), and pyloric (PY) neurons are active. 3. Tonic low-frequency lpln stimulation, alternatively, results in the VD neuron rhythmically firing long spike bursts with a cycle frequency much slower than that of the pyloric network while an otherwise complete pyloric pattern continues. In this new bursting pattern the VD neuron fires exclusively with another STS neural network, the cardiac sac (CS) network, and thus functionally "switches" from the pyloric to the CS network. This switch of the VD neuron from the pyloric to the CS network also occurs when the CS network is spontaneously active. 4. Our results thus demonstrate that sensory input can provoke a long-lasting modification of the functional configuration of a rhythmic neural network. They further extend the concept of flexibility in nervous systems by showing that individual neurons can belong to more than one neural network, "switching" from one to another in response to sensory input or spontaneous central nervous activity.J Neurophysiol 19906451555-7397401426 Hooper, S. L.ongPhase maintenance in the pyloric pattern of the lobster (Panulirus interruptus) stomatogastric ganglionoAnimal Female Ganglia, Autonomic/*physiology Gastrointestinal System/*physiology Lobsters/*physiology Male *Neural Networks (Computer) Pylorus/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.The extent to which individual neural networks can produce phase- constant motor patterns as cycle frequency is altered has not been studied extensively. I investigated this issue in the well-defined, rhythmic pyloric neural network. When pyloric cycle frequency is altered three- to fivefold, pyloric inter-neuronal delays shift by hundreds to thousands of msec, and all pyloric pattern elements show strong phase maintenance. The experimental paradigm used is unlikely to activate exogenous inputs to the network, and these delay changes are thus likely to arise from phase-compensatory mechanisms intrinsic to the network. Pyloric inter-neuronal delays depend on the time constants of the network's synapses and of the membrane properties of its neurons. The observed delay shifts thus suggest that, in response to changes in overall cycle frequency, these constants vary so as to maintain pattern phasing.J Comput Neurosci 199743191-205p x90331030*$Johnson, B. R. Harris-Warrick, R. M.b[Aminergic modulation of graded synaptic transmission in the lobster stomatogastric ganglionad]Action Potentials Animal Dopamine/pharmacology Electric Conductivity Ganglia/*physiology In Vitro Lobsters Membrane Potentials/drug effects Neurons/drug effects/*physiology Octopamine/pharmacology Serotonin/pharmacology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/drug effects/*physiology *Synaptic Transmission/drug effectsi@:Graded chemical synaptic transmission is important for establishing the motor patterns produced by the pyloric central pattern generator (CPG) circuit of the lobster stomatogastric ganglion (Raper, 1979; Anderson and Barker, 1981; Graubard et al., 1983). We examined the modulatory effects of the amines dopamine (DA), serotonin (5-HT), and octopamine (Oct) on graded synaptic transmission at all the central chemical synapses made by the pyloric dilator (PD) neuron onto its follower cells, using synaptic input-output curves measured from cell somata. DA strongly reduced the graded synaptic strength at all the PD synapses. DA reduction of chemical synaptic strength from PD onto the inferior cardiac (IC) neuron could change the sign of synaptic interaction between these 2 cells from inhibitory to excitatory by uncovering a weak electrical connection. 5-HT had weaker and more variable effects, reducing graded synaptic strength from the PD onto the lateral pyloric and pyloric neurons and enhancing the weak synapse from the PD to the IC cell. Oct strongly enhanced the graded synaptic strength at all the PD central synapses. Oct enhancement of graded synaptic strength between the PD and IC cells could also change the sign of the interaction: weak, excitatory electrical coupling, which was sometimes dominant before Oct, was masked by the enhanced chemical inhibitory interaction during Oct application. Measurements of electrical coupling between 2 PD cells and between 2 postsynaptic cells suggest that Oct does not change the input resistance of these cells and may act directly at the PD synapses. The effects of DA and 5-HT are most easily explained by their general reductions in pre- and postsynaptic input resistance. DA, 5-HT, and Oct each produce a distinct pyloric motor pattern (Flamm and Harris-Warrick, 1986a). These amine-induced motor patterns may be explained by the unique actions of each amine on the intrinsic membrane properties of different pyloric CPG neurons (Flamm and Harris-Warrick, 1986b) and by modulation of graded synaptic transmission between the pyloric neurons. J Neurosci 19901072066-769126871760Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.d^Temperature sensitivity of graded synaptic transmission in the lobster stomatogastric ganglionAction Potentials Animal Ganglia/cytology/*physiology Lobsters Motor Neurons/physiology Neurons/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiology Synaptic Transmission/*physiology TemperatureOWe examined the temperature sensitivity of graded chemical synaptic strength within the pyloric circuit of the spiny lobster stomatogastric ganglion. Cooling from 20.4 degrees C to 11.3 degrees C reduced the graded synaptic potential (GSP) amplitude at all six pyloric synapses tested. Cooling appeared to reduce the slope of the linear part of the input-output curve at three of these synapses, and did not significantly alter the threshold for transmitter release at any synapses. Pairs of neurons with a presynaptic pyloric dilator (PD) cell showed reductions in graded synaptic strength at 16.5 degrees C but those with presynaptic lateral pyloric (LP) or ventral dilator (VD) cells did not. A generalized decrease in input resistance is not responsible for the reduced GSP amplitude upon cooling, as determined by input resistance, action potential amplitude and electrical coupling measurements. We conclude that cooling reduces graded chemical strength by a direct synaptic action. Since the PD and VD cells use the same transmitter and act on some of the same postsynaptic cells, their differential sensitivity to cooling further suggests a presynaptic site of action. The temperature range used in our experiments encompasses the range that the animal normally encounters in nature. Thus, the relative importance of graded synaptic interactions in generating the pyloric motor rhythm may vary with transient changes in temperature. J Exp Biol 1991 156 267-85 Johnson, B.R. Hooper, S.Li 19922,Overview of thestomatogastric nervous system BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MA  MIT PressS 1-30v ^98204977 Hurley, L. M. Graubard, K.\VPharmacologically and functionally distinct calcium currents of stomatogastric neuronsVPAnimal Calcium Channel Blockers/*pharmacology Cells, Cultured *Crabs Ganglia, Invertebrate/cytology/*drug effects Male Membrane Potentials/drug effects Neuromuscular Junction/drug effects Neurons/*drug effects Patch-Clamp Techniques Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.@:Previous studies have suggested the presence of different types of calcium channels in different regions of stomatogastric neurons. We sought to pharmacologically separate these calcium channel types. We used two different preparations from different regions of stomatogastric neurons to screen a range of selective calcium channel blockers. The two preparations were isolated cell bodies in culture, in which calcium current was measured directly, and isolated neuromuscular junction, in which synaptic transmission was the indirect assay for presynaptic calcium influx. The selective blockers were two different dihydropyridines, omega-Agatoxin IVA, and omega-Conotoxin GVIA. Cultured cell bodies possessed both high-threshold calcium current and calcium-activated outward current, similar to intact neurons. The calcium current had transient and maintained components, but both components had the same voltage dependence of activation and inactivation. Dihydropyridines at >/=10 microM blocked both high- threshold calcium current and calcium-activated outward current. Nanomolar doses of omega-Agatoxin IVA did not block calcium current, but micromolar doses did. omega-Conotoxin GVIA did not block either current. In contrast, at the neuromuscular junction, dihydropyridines reduced the amplitude of postsynaptic potentials by only a modest amount, whereas omega-Agatoxin IVA at doses as low as 64 nM reduced the amplitude of postsynaptic potentials almost entirely. These effects were presynaptic. omega-Conotoxin GVIA did not change the amplitude of postsynaptic potentials. The different pharmacological profiles of the two isolated preparations suggest that there are at least two different types of calcium channel in stomatogastric neurons and that omega- Agatoxin IVA and dihydropridines can be used to pharmacologically distinguish them.J Neurophysiol 1998794i2070-81 Icely, J.D. Nott, J.A. 1984sOn the morphology and fine structure of the alimentary canal of Corophium volutator (Pallus) (Crustacea: Amphipoda)s@SPhil Trans Roy Soc B 306b 1126 49-78if_http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.cob.org.uk/JEB/191/1/jeb9309.html05$Jackel, C. Krenz, W. Nagy, F. VPBicuculline/Baclofen-Insensitive Gaba Response in Crustacean Neurones in CulturevpNeurones were dissociated from thoracic ganglia of embryonic and adult lobsters and kept in primary culture. When gamma-aminobutyric acid (GABA) was applied by pressure ejection, depolarizing or hyperpolarizing responses were produced, depending on the membrane potential. They were accompanied by an increase in membrane conductance. When they were present, action potential firing was inhibited. The pharmacological profile and ionic mechanism of GABA- evoked current were investigated under voltage-clamp with the whole- cell patch-clamp technique. The reversal potential of GABA-evoked current depended on the intracellular and extracellular Cl- concentration but not on extracellular Na+ and K+. Blockade of Ca2+ channels by Mn2+ was also without effect. The GABA-evoked current was mimicked by application of the GABAA agonists muscimol and isoguvacine with an order of potency muscimol>GABA>isoguvacine. cis-4-aminocrotonic acid (CACA), a folded and conformationally restricted GABA analogue, supposed to be diagnostic for the vertebrate GABAC receptor, also induced a bicuculline-resistant chloride current, although with a potency about 10 times lower than that of GABA. The GABA-evoked current was largely blocked by picrotoxin, but was insensitive to the GABAA antagonists bicuculline, bicuculline methiodide and SR 95531 at concentrations of up to 100 µmol l-1. Diazepam and phenobarbital did not exert modulatory effects. The GABAB antagonist phaclophen did not affect the GABA-induced current, while the GABAB agonists baclophen and 3-aminopropylphosphonic acid (3-APA) never evoked any response. Our results suggest that lobster thoracic neurones in culture express a chloride-conducting GABA-receptor channel which conforms to neither the GABAA nor the GABAB types of vertebrates but shows a pharmacology close to that of the novel GABAC receptor described in the vertebrate retina. 1994 J Exp Biol 1911 167-93 Using Smart Source Parsing76116225"Jahromi, S. S. Govind, C. K.LFUltrastructural diversity in motor units of crustacean stomach musclesAnimal Crabs/*anatomy & histology/physiology Membrane Potentials Muscle Contraction Muscle, Smooth/physiology/*ultrastructure Stomach/physiology/ultrastructure Synapses/physiologyrThe physiological and ultrastructural properties of muscle fiber.s comprising three motor units in the gastric mill of blue crabs are described. In their contractile properties muscle fibers in all motor units are similar and resemble the slow type fibers in crustacean limb muscles. The majority of fibers generate large excitatory post-synaptic potentials which do not facilitate strongly. Structurally two types of fibers are found. The one type has long sarcomeres (greater than 6 mum), thin to thick myofilament ratios of 5-6:1 and diads located near the ends of the A-band. The other type has shorter sarcomeres (less than 6 mum), thin to thick myofilament ratios of 3:1 and diads located at mid sarcomere level. Both types of fibers occur within a single motor unit and this differs from the vertebrate situation. Furthermore, the finding of fibers with a low thin to thick myofilament ratio of 3:1 demonstrates that they are not exclusive to fast type crustacean muscle but also occur in slow stomach muscles.Cell Tissue Res 1976 1662 159-66Johannen, K.C. 1991HBRhythmic motor patterns and their modulation in the intact lobsterBiology Maine Bowdoin College B.A. X `9606329760Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.zDistributed amine modulation of graded chemical transmission in the pyloric network of the lobster stomatogastric ganglionAnalysis of Variance Animal Biogenic Amine Neurotransmitters/*physiology Dopamine/physiology Ganglia, Invertebrate/cytology/*physiology In Vitro Lobsters/*physiology Membrane Potentials/drug effects/physiology Microelectrodes Neurons/*physiology Octopamine/physiology Pylorus/innervation/physiology Serotonin/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/drug effects/physiology Synaptic Transmission/*physiology Tetrodotoxin/pharmacology j d1. In the pyloric network of the lobster stomatogastric ganglion, graded synapses organize the network output. The amines dopamine (DA), serotonin, and octopamine each elicit a distinctive motor pattern from a quiescent pyloric network. We have examined the effects of these amines on the graded synaptic strengths between the six major types of neurons of this network to understand how amine modulation of synaptic strength contributes to the amine-induced motor patterns. Here we tested amine affects at 10 different graded chemical synapses of the pyloric network. We show that each amine has a statistically different spectrum of distributed effects across the network synapses. 2. Under our control conditions (isolated pairs of neurons, removal of modulatory input), most of the graded chemical synapses were weak and some synapses were nonfunctional. The output synapses of the ventricular dilator (VD) neuron were significantly stronger than the other synapses. 3. DA altered the synaptic strength of every graded chemical synapse. This amine strengthened the weak chemical output synapses of the anterior burster (AB), lateral pyloric (LP), and pyloric constrictor (PY) neurons and weakened (and in some cases abolished) the strong chemical output synapses of the VD neuron. The AB- ->inferior cardiac neuron (IC) and PY-->IC graded chemical synapses were nonfunctional under our control conditions; DA activated these silent synapses. 4. Serotonin enhanced the AB's output chemical synapses but weakened all the other graded chemical synapses examined. Octopamine's effects were much weaker than those of the other two amines. It enhanced the AB-->LP synapse and the LP's output synapses and weakly strengthened the AB-->PY, VD-->LP, and VD-->PY synapses. 5. The amines alter the input resistance of many of the pyloric neurons, and this could contribute to the observed changes in synaptic strength by altering passive current flow between input and output sites in the cells. However, the input resistance changes were relatively small compared with the changes in synaptic strength and cannot alone account for the synaptic modulation. In some cases the sign of the input resistance change was inconsistent with the change in synaptic strength. Thus the amines appear to modify synaptic transmission directly in this system. 6. This study completes our description of amine effects on all the graded synapses of the pyloric network. We summarize our present and earlier work to show that modulators can reconfigure the entire synaptic organization of a neural network by acting at many distributed synaptic sites.(ABSTRACT TRUNCATED AT 400 WORDS)J Neurophysiol 1995741 437-5298070655*$Johnson, B. R. Harris-Warrick, R. M.leAmine modulation of glutamate responses from pyloric motor neurons in lobster stomatogastric ganglionAcetylcholine/physiology Animal Biogenic Amine Neurotransmitters/*pharmacology Dopamine/pharmacology Ganglia, Invertebrate/drug effects Glutamic Acid/*pharmacology Iontophoresis Lobsters/*physiology Membrane Potentials/drug effects Motor Neurons/drug effects Nerve Net/drug effects Octopamine/pharmacology Pylorus/drug effects/innervation Serotonin/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.c^XThe amines dopamine (DA), serotonin (5-HT), and octopamine (Oct) each elicit a distinctive motor pattern from a quiescent pyloric network in the lobster stomatogastric ganglion (STG). We previously have demonstrated that these amines alter the synaptic strength at multiple, distributed sites within the pyloric network that could contribute to the amine-induced motor patterns. Here, we examined the postsynaptic contribution to these changes in synaptic strength by determining how the amines modify responses of pyloric motor neurons to glutamate (Glu), one of the network transmitters, applied iontophoretically into the STG neuropil. Dopamine reduced the Glu responses of the pyloric dilator (PD), ventricular dilator (VD), and inferior cardiac (IC) neurons and enhanced the Glu responses of the lateral pyloric (LP) and pyloric constrictor (PY) neurons. The only effect of 5-HT was to reduce the Glu response of the VD neuron. Oct enhanced the Glu responses of the LP and PY neurons but did not affect the PD, VD, and IC responses. We also examined amine effects on the depolarizing responses to iontophoresed acetylcholine (ACh) in the PD and VD and found that they paralleled the amine effects on Glu responses in these neurons. This suggests that amine modulation of PD and VD responses to Glu and ACh may be explained by general changes in the ionic conductance of these neurons. We compare our results with our earlier work describing amine effects on synaptic strength and input resistance to show that amines act at both pre- and postsynaptic sites to modify graded synaptic transmission in the pyloric network.J Neurophysiol 19977863210-2112904487902 2003 AughaDopamine modulation of calcium currents in pyloric neurons of the lobster stomatogastric ganglion 631-43NGWe examined the dopamine (DA) modulation of calcium currents (ICa) that could contribute to the plasticity of the pyloric network in the lobster stomatogastric ganglion. Pyloric somata were voltage-clamped under conditions designed to block voltage-gated Na+, K+, and H currents. Depolarizing steps from -60 mV generated voltage-dependent, inward currents that appeared to originate in electrotonically distal, imperfectly clamped regions of the cell. These currents were blocked by Cd2+ and enhanced by Ba2+ but unaffected by Ni2+. Dopamine enhanced the peak ICa in the pyloric constrictor (PY), lateral pyloric (LP), and inferior cardiac (IC) neurons and reduced peak ICa in the ventricular dilator (VD), pyloric dilator (PD), and anterior burster (AB) neurons. All of these effects, except for the AB, are consistent with DA's excitation or inhibition of firing in the pyloric neurons. Enhancement of ICa in PY and LP neurons and reduction of ICa in VD and PD neurons are also consistent with DA-induced synaptic strength changes via modulation of presynaptic ICa. However, the reduction of ICa in AB suggests that DA's enhancement of AB transmitter release is not directly mediated through presynaptic ICa. ICa in PY and PD neurons was more sensitive to nifedipine block than in AB neurons. In addition, nifedipine blocked DA's effects on ICa in the PY and PD neurons but not in the AB neuron. Thus the contribution of specific calcium channel subtypes carrying the total ICa may vary between pyloric neuron classes, and DA may act on different calcium channel subtypes in the different pyloric neurons.'pjDepartment of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA. BRJ1@Cornell.Edu:4Johnson, B. R. Kloppenburg, P. Harris-Warrick, R. M.("22786631 0022-3077 Journal ArticleJ Neurophysiol Animal Calcium Channel Blockers/pharmacology Calcium Channels/drug effects/*physiology Dopamine/*physiology Electrophysiology Neurons/drug effects/*physiology Nifedipine/pharmacology Palinuridae Patch-Clamp Techniques Pylorus/*innervation Support, U.S. Gov't, P.H.S.lehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12904487r ,9335343960Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.leAmine modulation of electrical coupling in the pyloric network of the lobster stomatogastric ganglion  Amines/*metabolism Animal Electric Conductivity Electrophysiology Ganglia/*physiology Neural Pathways/cytology/physiology Neurons/physiology Pylorus/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologys 1. The neurons of the pyloric network of the lobster (Panulirus interruptus) stomatogastric ganglion organize their rhythmic motor output using both chemical and electrical synapses. The 6 electrical synapses within this network help set the firing phases of the pyloric neurons during each rhythmic cycle. We examined the modulatory effects of the amines dopamine (DA), serotonin (5HT) and octopamine (Oct) on coupling at all the electrical synapses of the pyloric network. 2. Electrical coupling within the pacemaker group [anterior burster (AB) to pyloric dilator (PD), and PD-PD] was non-rectifying, while coupling at the other electrical synapses [AB to ventral dilator (VD), PD-VD, lateral pyloric (LP) to pyloric (PY), and PY-PY] was rectifying. 3. Dopamine decreased or increased the coupling strength of all the pyloric electrical synapses: the sign of the effect depended upon which neuron was the target of current injection. For example, DA decreased AB-->PD coupling (i.e., when current was injected into the AB) but increased coupling in the other direction, PD-->AB. Dopamine decreased AB to VD coupling when current was injected into either neuron. Serotonin also had mixed effects; it enhanced PD-->AB coupling but decreased AB to VD and PD to VD coupling in both directions. Octopamine's only effect was to reduce PD-->VD coupling. 4. Dopamine increased the input resistance of the AB neuron but decreased the input resistance of the PD and VD neurons. Serotonin reduced the input resistance of the VD and PY neurons, while Oct did not significantly change the input resistance of any pyloric neuron. 5. The characteristic modulation of electrical coupling by each amine may contribute to the unique motor pattern that DA, 5HT and Oct each elicit from the pyloric motor network. 1993J Comp Physiol [A] 172t6r 715-32 Using Smart Source Parsing9406157260Johnson, B. R. Peck, J. H. Harris-Warrick, R. M.JDDopamine induces sign reversal at mixed chemical-electrical synapses Animal Dopamine/*pharmacology Electrochemistry Ganglia, Invertebrate/drug effects/metabolism/physiology Lobsters Neurons/physiology Pylorus/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*drug effects/metabolism/*physiologyeA mixed chemical/electrical synapse can generate variable output when the strength of each synaptic component is modulated. At mixed synapses of the lobster pyloric network, the chemical component is inhibitory. Without neuromodulation, the chemical component is weak or absent and the electrical component often dominates. Dopamine reverses the sign of these mixed synaptic interactions by a reduction in the strength of electrical coupling and an enhancement of chemical inhibition, including activation of silent chemical synapses. Sign reversal at mixed synapses by neuromodulators may contribute to functional rewiring of neural networks. Brain Res 1993 6251 159-64  LFJorge-Rivera, J. C. Sen, K. Birmingham, J. T. Abbott, L. F. Marder, E.XQTemporal dynamics of convergent modulation at a crustacean neuromuscular junction ZSAnimal Crustacea Electric Stimulation Evoked Potentials/drug effects/physiology Male Motor Neurons/drug effects/physiology Muscle Contraction/drug effects/physiology Muscle Relaxation/drug effects/physiology Neuromuscular Junction/drug effects/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.At least 10 different substances modulate the amplitude of nerve-evoked contractions of the gastric mill 4 (gm4) muscle of the crab, Cancer borealis. Serotonin, dopamine, octopamine, proctolin, red pigment concentrating hormone, crustacean cardioactive peptide, TNRNFLRFamide, and SDRNFLRFamide increased and -allatostatin-3 and histamine decreased the amplitude of nerve-evoked contractions. Modulator efficacy was frequency dependent; TNRNFLRFamide, proctolin, and allatostatin-3 were more effective when the motor neuron was stimulated at 10 Hz than at 40 Hz, whereas the reverse was true for dopamine and serotonin. The modulators that were most effective at high stimulus frequencies produced a significant decrease in muscle relaxation time; those that were most effective at low stimulus frequencies produced modest increases in relaxation time. Thus modulator actions that appear redundant when examined only at one stimulus frequency are differentiated when a range of stimulus dynamics is studied. The effects of TNRNFLRFamide, serotonin, proctolin, dopamine, and - allatostatin-3 on the amplitude and facilitation of nerve-evoked excitatory junctional potentials (EJPs) in the gm4 and gastric mill 6 (gm6) muscles were compared. The EJPs in gm4 have a large initial amplitude and show relatively little facilitation, whereas the EJPs in gm6 have a small initial amplitude and show considerable facilitation. Modulators that enhanced contractions also enhanced EJP amplitude; - allatostatin-3 reduced EJP amplitude. The effects of these modulators on EJP amplitude were modest and showed no significant frequency dependence. This suggests that the frequency dependence of modulator action on contraction results from effects on excitation-contraction coupling. The modulators affected facilitation at these junctions in a manner consistent with a change in release probability. They produced a change in facilitation that is inversely related to their action on EJP amplitude.'b\Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454, USA.9819263http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9819263 http://jn.physiology.org/cgi/content/full/80/5/2559J Neurophysiol 19988052559-70. Katz, P.S. 1989b[Motor pattern modulation by serotonergic sensory cells in the stomatogastric nervous system  Ithaca, NY Cornell University Ph.D.\ |ne/pharmacology89361606(!Katz, P. S. Harris-Warrick, R. M.aSerotonergic/cholinergic muscle receptor cells in the crab stomatogastric nervous system. II. Rapid nicotinic and prolonged modulatory effects on neurons in the stomatogastric ganglion*#Animal Crabs/*physiology Ganglia/*cytology/drug effects/physiology Gastrointestinal System/*innervation Muscarine/*antagonists & inhibitors Neurons, Afferent/drug effects/*physiology Nicotine/*antagonists & inhibitors Serotonin/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.( " 1. The gastropyloric receptor (GPR) cells, which are described in the preceding paper, are a set of proprioceptive cells in the crabs Cancer borealis and Cancer irroratus that contain serotonin (5- hydroxytryptamine, 5-HT) and choline acetyltransferase. These cells have a variety of synaptic effects on cells in the stomatogastric ganglion (STG). We used pharmacologic methods to distinguish the effects that were due to acetylcholine (ACh) from those that could be due to serotonin. 2. The GPR cells evoke excitatory postsynaptic potentials (EPSPs) in two gastric mill motor neurons [lateral and dorsal gastric (LG and DG)] in the stomatogastric ganglion. The EPSPs exhibit nicotinic pharmacology, indicating that they may be due to the release of ACh from the GPR cells. 3. A train of GPR action potentials induces plateau potential properties in the DG motor neuron. This plateau potential induction is not blocked by nicotinic or muscarinic antagonists, suggesting it might be due to serotonin released from the GPR cells. Bath-applied serotonin induces a tonic depolarization of DG with high-intensity spiking. 4. In the accompanying paper, it is shown that DG-evoked muscle contraction leads to the excitation of GPR2 through mechanical coupling of the muscles. Because GPR2 also excites DG, a positive feedback loop exists between GPR2 and DG. This reflex loop may be involved in the control of the medial tooth of the gastric mill. 5. GPR stimulation initiates or enhances rhythmic pyloric cycling. This is due at least in part to a direct enhancement of bursting in the pyloric dilator/anterior burster (PD/AB) pacemaker cell group and can outlast the period of GPR stimulation by up to 1 min. GPR- induced PD burst enhancement continues in the presence of nicotinic and muscarinic antagonists, indicating that the effect is probably not due to the release of ACh. Bath application of serotonin mimicks the neuromodulatory effect of GPR stimulation on the PD/AB group by inducing or enhancing bursting. 6. Thus the GPR cells elicit at least three different synaptic actions in the stomatogastric ganglion: 1) classical, fast nicotinic cholinergic EPSPs that may be important for reflex functions in the gastric mill; 2) noncholinergic, cycle-by-cycle plateau potential induction that might be critical for the timing and operation of the gastric mill, and 3) prolonged, noncholinergic burst enhancement in pyloric neurons that is mimicked by serotonin, lasts many cycles, and may act to assure that the pyloric central pattern generator (CPG) is activated and cycling strongly.J Neurophysiol 1989622 571-81&Katz, P.S. Harris-Warrick, R.M. 1989A new role for proprioceptive geedback to CPGS: Neuromodulation by serotonergic/cholinergic mechanosendory afferents to the stomatogastric ganglion of crabs 0)Erber, J. Menzel, R. Pfluger, H. Todt, D.o$Neural Mechanisms of Behavior  Stuttgart Georg Thieme Verlag 229  ne/*physiology Jones, B.R. Hartline, D.K. 1991NHUnusual properties of outward currents in lobster stomatogastric neurons Biophys J59 26797114814$Jorge-Rivera, J. C. Marder, E.piTNRNFLRFamide and SDRNFLRFamide modulate muscles of the stomatogastric system of the crab Cancer borealisrjcAnimal Crabs/*physiology Evoked Potentials/physiology Gastrointestinal System/innervation/*physiology Invertebrate Hormones/*physiology Male Microelectrodes Motor Neurons/physiology Muscle Contraction/physiology Muscles/innervation/*physiology Neuromuscular Junction/physiology Neuropeptides/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.gThe effects of the extended FLRFamide-like peptides, TNRNFLRFamide and SDRNFLRFamide, were studied on the stomach musculature of the crab Cancer borealis. Peptide-induced modulation of nerve-evoked contractions was used to screen muscles. All but 2 of the 17 muscles tested were modulated by the peptides. In several muscles of the pyloric region, peptides induced long-lasting myogenic activity. In other muscles, the peptides increased the amplitude of nerve-evoked contractions, excitatory junctional potentials, and excitatory junctional currents, but produced no apparent change in the input resistance of the muscle fibers. The threshold concentration was 10(- 10) M for TNRNFLRFamide and between 10(-9) M to 10(-8) M for SDRNFLRFamide. The absence of direct peptide-containing innervation to these muscles and the wide-spread sensitivity of these muscles to the peptides suggest that TNRNFLRFamide and SDRNFLRFamide may be released from neurosecretory structures to modulate stomatogastric musculature hormonally. We speculate that hormonally released peptide will be crucial for maintaining appreciable muscle contraction in response to low-frequency and low-intensity motor discharge. J Comp Physiol [A] 1996 179(6o 741-51 Llf`http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.cob.org.uk/JEB/200/23/jeb1087.html98028703$Jorge-Rivera, J. Marder, Y. E.b\Allatostatin decreases stomatogastric neuromuscular transmission in the crab Cancer borealisAcetylcholine/pharmacology/physiology Animal Crabs/*drug effects/*physiology Glutamic Acid/pharmacology/physiology Insect Hormones/*pharmacology/physiology Male Muscle Contraction/drug effects Neuromuscular Junction/drug effects/physiology Neuropeptides/*pharmacology/physiology Stomach/drug effects/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synaptic Transmission/drug effects~xThe effects of insect allatostatins (ASTs) 1-4 were studied on the stomach musculature of the crab Cancer borealis. Of these, Diploptera- allatostatin 3 (D-AST-3) was the most effective. D-AST-3 (10(-6 )mol l- 1) reduced the amplitude of nerve-evoked contractions, excitatory junctional potentials and excitatory junctional currents at both cholinergic and glutamatergic neuromuscular junctions. Muscle fiber responses to ionophoretic applications of both acetylcholine and glutamate were reduced by the peptide, but D-AST-3 produced no apparent change in the input resistance of the muscle fiber. D-AST-3 reduced the amplitude of muscle contractures evoked by both acetylcholine and glutamate, but had no effect on contractures induced by a high [K+]. These data suggest that D-AST-3 decreases the postsynaptic actions of both neurally released acetylcholine and glutamate. Because an AST-like peptide is found in peripheral sensory neurons that innervate stomatogastric muscles and in the pericardial organs, we suggest that an AST-like peptide may play a role in controlling the gain of the excitatory neuromuscular junctions in the stomach. J Exp Biol 1997 200c Pt 23d2937-46y :{Neuronal Plasticity$Neuronal Plasti893616054-Katz, P. S. Eigg, M. H. Harris-Warrick, R. M.WSerotonergic/cholinergic muscle receptor cells in the crab stomatogastric nervous system. I. Identification and characterization of the gastropyloric receptor cellsAcetylcholine/*physiology Animal Crabs/*physiology Ganglia/*cytology/physiology Gastrointestinal System/*innervation Neurons, Afferent/*physiology Serotonin/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. 1. Serotonin (5-hydroxytryptamine) immunohistochemistry was used to locate and anatomically describe a set of four muscle receptor cells in the stomatogastric nervous system of the crabs Cancer borealis and Cancer irroratus. We found that these sensory cells, which we named gastropyloric receptor (GPR) cells, are the sole source of serotonergic inputs to the stomatogastric ganglion (STG) in these species. Thus any endogenous serotonergic modulation of the central pattern generators (CPGs) in the STG must be afferent and not descending from other ganglia. 2. There are two bilateral pairs of GPR cells. Each pair consists of two cell types (GPR1 and GPR2) based on differences in muscle innervation and physiological response characteristics. GPR2 responds in a mostly tonic fashion to increases in muscle tension caused by passive stretch or motor neuron-evoked contraction, whereas GPR1 responds more phasically and adapts more rapidly. Both GPR cell types project to the midline STG and terminate in each of the bilaterally paired commissural ganglia (COGs). 3. The GPR cells have sensory endings unlike any described for other muscle receptor cells: the terminals enter invaginations of the muscle surface and end near the z-bands of the muscle. These novel structures may be involved in the sensory transduction process. 4. The GPR cells may contain acetylcholine in addition to serotonin, as indicated by the presence of choline acetyltransferase (ChAT) in GPR2 (Table 1) and probably GPR1 as well. 5. The GPR cells have no direct effect on muscle properties or neuromuscular transmission: excitatory junctional potential (EJP) amplitude and motor neuron-evoked tension are unaffected by GPR stimulation. However, very low concentrations of exogenously applied serotonin do cause an increase in motor neuron-evoked muscle tension, probably reflecting a hormonal action of the amine. 6. The activity of GPR2 was monitored in a semi-intact preparation. GPR2 is active in phase with normal movements of the gastric mill. GPR2 is also capable of endogenous rhythmic activity. This indicates that even in the absence of mechanical stimulation, the GPR cells may still provide patterned input to the CPGs in the STG. 7. The GPR cells are proprioceptive cells that use serotonin and acetylcholine as cotransmitters. It is important to characterize these cells to understand the role of serotonergic modulation in the production of motor programs by stomatogastric CPGs.J Neurophysiol 1989622 558-70 o:p}(#Serotonin/*isolation & purificationSerotonin/*pharmacologySerotonin/*physiologySerotonin/*secretionSerotonin/analysis$ Serotonin/immunology/*physiologySerotonin/metabolismSerotonin/pharmacology("Serotonin/pharmacology/*physiologySerotonin/physiologyShrimp/*physiology($Signal Processing, Computer-Assisted$Signal Transduction/*physiology$ Signal Transduction/drug effects0+Signal Transduction/drug effects/physiologySmell/physiology Sodium Channels/drug effects,'Sodium Channels/drug effects/physiology Sodium Channels/physiologySodium/*physiologySodium/metabolismSodium/physiology$Somatosensory Cortex/physiologySpecies SpecificityD?Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization($Spinal Cord Injuries/physiopathologySpinal Cord/*physiologySpinal Cord/physiology StainingStaining and LabelingStimulation, ChemicalStochastic Processes StomachStomach/*innervation$Stomach/*innervation/physiologyStomach/*physiology83Stomach/anatomy & histology/innervation/*physiologyStomach/chemistry,'Stomach/cytology/innervation/physiology$ Stomach/drug effects/innervationStomach/injuriesStomach/innervation$Stomach/innervation/*physiology$Stomach/innervation/physiology,&Stomach/innervation/physiology/surgery Stomach/metabolism/physiologyStomach/physiology$!Stomach/physiology/ultrastructure("Stomatognathic System/*innervationStrontium/pharmacology$Structure-Activity Relationship4/Substance P/*analogs & derivatives/pharmacologySubstance P/*analysisSubstance P/*pharmacology4.Substance P/analogs & derivatives/pharmacologySubstance P/analysisSubtilisins/pharmacologySucrose/pharmacologySupport, Non-U.S. Gov't$Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Swimming/physiology("Synapses/*drug effects/*physiology0-Synapses/*drug effects/metabolism/*physiologySynapses/*physiology(#Synapses/*physiology/ultrastructureSynapses/*ultrastructure Synapses/chemistry/physiologySynapses/drug effects$!Synapses/drug effects/*metabolism$!Synapses/drug effects/*physiology$ Synapses/drug effects/physiologySynapses/metabolism(#Synapses/metabolism/*ultrastructureSynapses/physiology(#Synapses/physiology/*ultrastructure("Synapses/physiology/ultrastructureSynapsins/analysisSynaptic depressionsynaptic dynamics$Synaptic Membranes/drug effectsSynaptic Transmission(#Synaptic Transmission/*drug effects$!Synaptic Transmission/*physiology("Synaptic Transmission/drug effects4.Synaptic Transmission/drug effects/*physiology$ Synaptic Transmission/physiologySynaptic Vesicles$!Synaptic Vesicles/*ultrastructure0+Synaptic Vesicles/secretion/*ultrastructure$ Synaptic Vesicles/ultrastructure<9Tachykinins/*analysis/isolation & purification/metabolism40Tachykinins/*metabolism/pharmacology/*physiologyTachykinins/analysis4/Tachykinins/antagonists & inhibitors/metabolismTachykinins/metabolismTachykinins/pharmacology Tannic Acid Temperature,'Tendons/*anatomy & histology/physiology$!Tetanus Toxin/genetics/metabolism,)Tetraethylammonium Compounds/pharmacology Tetrodotoxin/*pharmacologyTetrodotoxin/pharmacology(#Theophylline/*analogs & derivativesThorax/innervation Time FactorsTissue CultureTissue DistributionTissue FixationTooth/*innervation Tooth/innervation/physiologyTooth/physiology("Transcription, Genetic/*physiologyTrimethaphan/pharmacologyTubocurarine/pharmacologyTubulin/metabolism$!Tyrosine 3-Monooxygenase/analysis4/Tyrosine 3-Monooxygenase/immunology/*metabolism(#Tyrosine 3-Monooxygenase/metabolismVertebrates/physiology Wave formWeight-Bearing Xenopus Xenopus/genetics/metabolismtic dynamicsphase maintenance4-Nadim, F. Manor, Y. Nusbaum, M. P. Marder, E.  1998D>Frequency regulation of a slow rhythm by a fast periodic input J Neurosci18135053-67i98299896Many nervous systems contain rhythmically active subnetworks that interact despite oscillating at widely different frequencies. The stomatogastric nervous system of the crab Cancer borealis produces a rapid pyloric rhythm and a considerably slower gastric mill rhythm. We construct and analyze a conductance-based compartmental model to explore the activation of the gastric mill rhythm by the modulatory commissural neuron 1 (MCN1). This model demonstrates that the period of the MCN1-activated gastric mill rhythm, which was thought to be determined entirely by the interaction of neurons in the gastric mill network, can be strongly influenced by inhibitory synaptic input from the pacemaker neuron of the fast pyloric rhythm, the anterior burster (AB) neuron. Surprisingly, the change of the gastric mill period produced by the pyloric input to the gastric mill system can be many times larger than the period of the pyloric rhythm itself. This model illustrates several mechanisms by which a fast oscillatory neuron may control the frequency of a much slower oscillatory network. These findings suggest that it is possible to modify the slow rhythm either by direct modulation or indirectly by modulating the faster rhythm.nghttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/18/13/50532 | 91020406(!Katz, P. S. Harris-Warrick, R. M.pLFActions of identified neuromodulatory neurons in a simple motor systemAnimal Crustacea Motor Neurons/*physiology Neurotransmitters/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Recent work on neurons that release slow neuromodulators has revealed important generalities about the roles played by neuromodulation in motor systems. Activity of these cells can affect the cellular and synaptic properties of central pattern generating circuits, orchestrating new variations of motor patterns and sometimes coordinating their outputs with other motor patterns. Many modulatory neurons use multiple transmitters to evoke both fast and slow synaptic responses of various types in different target cells. Some modulatory cells can have a mediating as well as a modulating role, simultaneously acting as sensory neurons or components of another pattern generating circuit.cTrends Neuroscir 1990139e 367-7390237878(!Katz, P. S. Harris-Warrick, R. M. xrNeuromodulation of the crab pyloric central pattern generator by serotonergic/cholinergic proprioceptive afferentsAnimal Brain/*physiology Crabs/*physiology Electric Stimulation Electrophysiology Motor Activity/physiology Neural Inhibition Neurons, Afferent/physiology Nicotine/metabolism Parasympathetic Nervous System/cytology/*physiology Proprioception/*physiology Pylorus/cytology/*innervation Serotonin/pharmacology/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology*#In the stomatogastric nervous system of the crab, Cancer borealis, a set of 4 serotonergic/cholinergic proprioceptive neurons, called gastropyloric receptor (GPR) cells, have effects on the pyloric motor pattern. In a semi-intact foregut preparation, the GPR cells are not activated by movements of the pyloric filter; instead they respond to the slower movements of the gastric mill (Katz et al., 1989). Thus, their activity is not synchronized to the pyloric motor pattern. However, when the GPR cells are stimulated in an in vitro preparation in a manner that resembles their normal firing pattern, they produce dramatic effects on the pyloric motor pattern. These effects include: (1) a prolonged increase in the pyloric cycle frequency, (2) a momentary pause in the motor pattern, (3) transient inhibition of some motor neurons, (4) strong excitation of other motor neurons, and (5) altered phase relationships of the different components of the motor pattern. These changes in the motor pattern are due to direct effects of the GPR cells on neurons in the pyloric central pattern generator (CPG). All of the cells in the pyloric circuit appear to receive GPR input. However, only 2 neurons receive detectable rapid nicotinic synaptic potentials. The other neurons receive only slower neuromodulatory input from GPR stimulation. The neuromodulatory effects include burst enhancement, plateau potential enhancement, excitation, and inhibition. These modulatory effects are largely mimicked by bath- applied serotonin (5-HT). Thus, primary sensory neurons can alter the production of motor patterns by a CPG through a phase-independent mechanism; these proprioceptors do not need to fire at a precise time in the cycle to be effective because their effects are mediated through the slower actions of the neuromodulator 5-HT. J Neurosci 1990105a1495-512 Katz, P.S. 1991@:Neuromodulation and the evolution of a simple motor system SINS3379-38991341572(!Katz, P. S. Harris-Warrick, R. M.tnRecruitment of crab gastric mill neurons into the pyloric motor pattern by mechanosensory afferent stimulationAcetylcholine/pharmacology Animal Crabs/*physiology Dendrites/physiology Evoked Potentials/drug effects/physiology Gastrointestinal Motility/drug effects/*physiology Microelectrodes Neurons, Afferent/drug effects/*physiology Parasympatholytics/pharmacology Physical Stimulation Picrotoxin/pharmacology Pirenzepine/pharmacology Pylorus/*innervation Recruitment (Neurology)/*physiology Scopolamine/pharmacology Serotonin/metabolism Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology Tubocurarine/pharmacologyo1. The gastropyloric receptor (GPR) cells are stretch-sensitive muscle receptors in the crab stomatogastric nervous system that use both 5- hydroxytryptamine (serotonin) and acetylcholine as cotransmitters. Brief stimulation of these afferent neurons causes two gastric mill neurons to be recruited into the pyloric motor pattern. 2. The GPR cells evoke complex synaptic potentials in the lateral gastric (LG) and medial gastric (MG) motor neurons, two component neurons of the gastric mill central pattern generator. When the gastric mill is quiescent (as often happens in vivo), GPR stimulation transiently inhibits LG and MG. After this transient inhibition, these cells undergo a prolonged excitation during which they fire bursts of action potentials at a constant phase relation to the pyloric motor pattern. 3. To determine the causes for this effect, we examined the effects of GPR stimulation on these two cells and on the inferior cardiac motor neuron, which is electrically coupled to them. When GPR is stimulated, all three cells receive rapid biphasic synaptic potentials that are blocked by nicotinic antagonists, followed by a slow, prolonged depolarizing potential. 4. The slow, prolonged depolarizing potential is not blocked by nicotinic or muscarinic cholinergic antagonists but is mimicked and occluded by exogenously applied serotonin. 5. The prolonged excitation, mediated at least in part by serotonin, may be responsible for the recruitment of the gastric mill neurons into the pyloric motor pattern. Thus sensory input can directly exert prolonged modulatory effects that change the functional cellular composition of pattern-generating circuits.tJ Neurophysiol 1991656t1442-51rKatz, P.S. Tazaki, K. 1992RLComparative and evolutionary aspects of the crustacean stomatogastric system BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MAy  MIT Pressi221-262("Katz, P.S. Kirk, M.D. Govind, C.K. 1993yFacilitation and depression at different branches of the same motor axon: Evidence for presynaptic differences in release J Neurosci13 3075-3089k Katz, P.S. 1995^XNeuromodulation and motor pattern generation in crustacean stomatogastric nervous system Ferrell, W.R. Proske, U."Neural Control of Movements New York  Plenum press277-283aE Kopell1994F Kopell1994^ Kopell19944{ Kopell1997 Kopell19977* Kopell1998Q Kopell19999 Kopell1999 Kravitz1972( Kravitz1983 Krenz1994+ Krenz2000 Kumar1990, Kunze19760 Kushner1977 Kushner1979- Kushner1979/ Kushner1983 Kushner1987. Kushner1987 Kwan19787 Labenia2000 Lange1989 Lanning1997% Lanning1997 Lanning2000! 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Lingle1981@ Lingle1981A Lingle1982; Lingle1983< Lingle1983= Lingle1983> Lingle1983 Lingle1986 Lingle1987q Liu1996B Liu1998CLnenicka1985DLnenicka1986E LoFaro1994F LoFaro1994G Lovett1989H Lovett1990 Lubell19969 Lubics19999P Lundquist1997 Luther20012I Luther2003J MacLean2003 MacLean2003K Macmillan1976 Macmillan1976w Mahadevan2001L Mamiya2003 Mamiya2004M Mancillas1984 Manhas20044 Mann19869P Manor1997| Manor1998 Manor1998# Manor1999 Manor1999Q Manor1999 Manor1999 Manor2000N Manor2001O Manor2001 Manor2001L Manor2003 Manor2003 Manor2003 Manor2004 Manor2004 Manor2005R Marder1974 Marder1976S Marder1976 Marder1978 Marder1980 Marder1980? Marder1981@ Marder1981 Marder1982A Marder1982T Marder1982 Marder1983' Marder1984i Marder1984 Marder1984U Marder1984V Marder1984u Marder1984v Marder1984x Marder1985 Marder1986 Marder19869y Marder1986 Marder1987W Marder1987X Marder1987 Marder19888Y Marder1988 Marder19888x Marder19899Z Marder1989[ Marder1989} Marder1989~ Marder1989 Marder19899 Marder19899 Marder19899 Marder19899z Marder19909 Marder19900 Marder19909 Marder1990 Marder19900 Marder1991 Marder1991i Marder1991\ Marder1991] Marder1991^ Marder1991 Marder19911 Marder1991 Marder199118 Marder19922 Marder19922 Marder19929 Marder19929 Marder19922 Marder1992n Marder1992 Marder1992 Marder1992 Marder1992 Marder19922 Marder19929F Marder1992 Marder19939 Marder19933 Marder19935 Marder19939_ Marder1993m Marder1993p Marder1993 Marder19939G Marder1993H Marder1993_ Marder19931 Marder19931 Marder19933 Marder1994O Marder19949E Marder1994F Marder1994` Marder1994a Marder1994o Marder1994J Marder1994^ Marder19944 Marder19941 Marder199440 Marder19959K Marder19959L Marder19959l Marder1995t Marder1995 Marder1995 Marder19959 Marder1996a$ Marder1996b Marder1996q Marder1996s Marder1996D Marder1996aI Marder19966 Marder19961M Marder19977 Marder19979 Marder1997aP Marder1997c Marder1997z Marder1997{ Marder1997 Marder1997a Marder1998 Marder19981B Marder19989d Marder1998e Marder1998| Marder1998 Marder1998 Marder19988 Marder19988# Marder1999Lanning2000! Lanning2001 Lanning2002 Lanning20042 Larimer19661 Larimer1988qLaverack1969KLaverack19766 Laverack19799 Laverack197993 Le Feuvre19994 Le Feuvre2001) Le Feuvre2002k Le Moal1984[ Legeay19989LeMasson19935LeMasson1993LeMasson1993ooLeMasson1994Lengvari19996 Levi2003 Levini19959 Levini1997 Levini19977( Levini19998 Li20027 Li20039 Lingle1980: Lingle1981? Lingle1981@ Lingle1981A Lingle1982; Lingle1983< Lingle1983= Lingle1983> Lingle1983 Lingle1986̱ Lingle1987q Liu1996B Liu1998CLnenicka1985DLnenicka1986E LoFaro1994F LoFaro1994G Lovett1989H Lovett1990 Lubell19969 Lubics19999P Lundquist1997 Luther20012I Luther2003J MacLean2003K Macmillan1976w Mahadevan2001L Mamiya2003M Mancillas1984 Mann19869P Manor1997| Manor1998 Manor1998# Manor1999 Manor1999Q Manor1999 Manor1999 Manor2000N Manor2001O Manor2001 Manor2001L Manor2003 Manor2003R Marder1974 Marder1976S Marder1976̀ Marder1978́ Marder1980̂ Marder1980? Marder1981@ Marder1981̂ Marder1982A Marder1982T Marder1982 Marder1983' Marder1984i Marder1984 Marder1984U Marder1984V Marder1984u Marder1984v Marder1984x Marder1985 Marder1986 Marder19869y Marder1986 Marder1987W Marder1987X Marder1987̣ Marder19888Y Marder1988 Marder19888x Marder19899Z Marder1989[ Marder1989} Marder1989~ Marder1989 Marder19899 Marder19899 Marder19899z Marder19909 Marder19900 Marder19909 Marder1990 Marder1991 Marder1991i Marder1991\ Marder1991] Marder1991^ Marder1991̚ Marder19911 Marder19918 Marder19922 Marder19922 Marder19929 Marder19929 Marder19922 Marder1992n Marder1992̇ Marder1992̉ Marder1992̊ Marder1992̠ Marder19922 Marder19929F Marder1992 Marder19939 Marder19933 Marder19935 Marder19939_ Marder1993m Marder1993p Marder1993 Marder19939G Marder1993H Marder1993_ Marder19931 Marder1994O Marder19949E Marder1994F Marder1994` Marder1994a Marder1994o Marder1994J Marder1994^ Marder199440 Marder19959K Marder19959L Marder19959l Marder1995t Marder1995 Marder1995  Marder1996a$ Marder1996b Marder1996q Marder1996s Marder1996D Marder1996aI Marder19966M Marder19977 Marder19979  Marder1997aP Marder1997c Marder1997z Marder1997{ Marder1997 Marder1998  Marder19981B Marder19989d Marder1998e Marder1998| Marder1998̃ Marder1998 Marder19988# Marder1999:vXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=8820868Katz, P. S. Frost, W. N.HAIntrinsic neuromodulation: altering neuronal circuits from within.haAnimal Human *Instinct *Nervous System Physiology Neurons/*physiology Support, U.S. Gov't, P.H.S.sThere are two sources of neuromodulation for neuronal circuits: extrinsic inputs and intrinsic components of the circuits themselves. Extrinsic neuromodulation is known to be pervasive in nervous systems, but intrinsic neuromodulation is less recognized, despite the fact that it has now been demonstrated in sensory and neuromuscular circuits and in central pattern generators. By its nature, intrinsic neuromodulation produces local changes in neuronal computation, whereas extrinsic neuromodulation can cause global changes, often affecting many circuits simultaneously. Studies in a number of systems are defining the different properties of these two forms of neuromodulation.-'`ZDept of Neurobiology and Anatomy, University of Texas Medical School, Houston, 77030, USA.8820868dTrends Neurosci  1996192r 54-61.76230156Kehoe, J. Marder, E.HBIdentification and effects of neural transmitters in invertebratesAcetylcholine/physiology Animal Arthropods/physiology Blood Vessels/physiology Chemistry Dopamine/physiology Ganglia/physiology Gills/physiology Glutamates/physiology Heart/physiology Invertebrates/*physiology Mollusca/physiology Muscles/physiology Neurotransmitters/isolation & purification/*physiology Octopamine/physiology Serotonin/physiology Support, U.S. Gov't, P.H.S. Synapses/physiology Synaptic Transmission 1976 Annu Rev Pharmacol Toxicol16 245-68 Using Smart Source ParsingKennedy, M.B. Marder, E. 1992<6Cellular and molecular mechanisms of neural plasticity  Hall, Z.H.0)An Introduction to Molecular Neurobiology Sunderland, MA Sinauer Associates, Inc.463-495x90208342,&Kepler, T. B. Marder, E. Abbott, L. F.VPThe effect of electrical coupling on the frequency of model neuronal oscillatorsAction Potentials Biological Clocks Electric Conductivity Electrophysiology Mathematics Membrane Potentials *Models, Biological Neurons/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. *#Neurons with oscillatory properties are a common feature of the nervous system, but little is known about how neural oscillators shape the behavior of neuronal networks or how network interactions influence the properties of neural oscillators. Mathematical models are used to examine the effect of electrically coupling an oscillatory neuron to a second neuron that is either silent or tonically firing. Models of oscillatory neurons with varying degrees of complexity show that this coupling can either increase or decrease the frequency of an oscillator, depending on its membrane potential wave form, the state of the neuron to which it is coupled, and the strength of the coupling. Thus, electrical coupling provides a flexible mechanism for modifying the behavior of an oscillatory neural network.Science 1990 248 4951 83-5*$Kepler, T.B. Abbott, L.F. Marder, E. 1991VPOrder reduction for dynamical systems describing the behavior of complex neurons .(Lippmann, R.P. Moody, J.E. Touretzky, D.81Advances in Neural Information Processing Systems  San Mateo, CAw Morgan Kaufman Publisherst3 55-61a92223170,&Kepler, T. B. Abbott, L. F. Marder, E.2,Reduction of conductance-based neuron modelsMathematics Membrane Potentials *Models, Neurological *Neural Conduction Neurons/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.We present a scheme for systematically reducing the number of differential equations required for biophysically realistic neuron models. The techniques are general, are designed to be applicable to a large set of such models and retain in the reduced system as high a degree of fidelity to the original system as possible. As examples, we provide reductions of the Hodgkin-Huxley system and the A-current model of Connor et al. (1977).  1992 Biol Cybernt665  381-7  Using Smart Source Parsing93200204Kepler, T. B. Marder, E.JCSpike initiation and propagation on axons with slow inward currentsAction Potentials/physiology Animal Axons/*physiology Cybernetics Electric Conductivity Electric Stimulation Electrophysiology Models, Neurological Support, U.S. Gov't, P.H.S.n81We investigate spike initiation and propagation in a model axon that has a slow regenerative conductance as well as the usual Hodgkin-Huxley type sodium and potassium conductances. We study the role of slow conductance in producing repetitive firing, compute the dispersion relation for an axon with an additional slow conductance, and show that under appropriate conditions such an axon can produce a traveling zone of secondary spike initiation. This study illustrates some of the complex dynamics shown by excitable membranes with fast and slow conductances.r 1993 Biol Cyberni683D 209-14 Using Smart Source ParsingXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=1708539 Kiehn, O.yb[Plateau potentials and active integration in the 'final common pathway' for motor behaviournAction Potentials/*physiology Animal Cats Decerebrate State Lampreys/physiology Motor Neurons/*physiology Neural Pathways/physiology Spinal Cord/*physiologyMost studies of vertebrate spinal motoneurones have suggested that they possess relatively simple membrane properties, causing them to behave merely as passively driven output neurones in motor behaviour. According to this concept, motoneurones passively transform the net synaptic drive from pre-motoneuronal levels into spike trains. Recent research has demonstrated a more complex picture by showing that motoneurones can express nonlinear intrinsic response properties, such as plateau potentials and endogenous oscillatory properties. This work suggests that the 'final common pathway' is actively involved in shaping motor behaviour.o'JCInstitute of Neurophysiology, Panum Institute, Copenhagen, Denmark.e1708539mTrends Neuroscig 1991142l 68-73.! l 92407593&Kiehn, O. Harris-Warrick, R. M.|uSerotonergic stretch receptors induce plateau properties in a crustacean motor neuron by a dual-conductance mechanism{Acetylcholine/pharmacology Animal Cesium/pharmacology Crabs/*physiology Electrophysiology Evoked Potentials/drug effects Mechanoreceptors/*physiology Motor Neurons/*physiology Parasympatholytics/pharmacology Serotonin/*physiology Stomach/cytology/innervation/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetrodotoxin/pharmacologyc R L1. The mechanisms for induction of bistable plateau potential properties by a set of serotonergic/cholinergic peripheral stretch receptor cells [gastropyloric receptor (GPR) cells] were examined in the crab stomatogastric ganglion (STG) with the use of intracellular recording techniques. 2. GPR cell stimulation evoked nicotinic excitatory postsynaptic potentials (EPSPs) and induced plateau potential capability in the dorsal gastric (DG) motor neuron. The plateau potential could be triggered during a GPR train either by the summating nicotinic EPSPs or by brief intracellular current injection. After pharmacological blockade of nicotinic and muscarinic receptors, a slow depolarization in response to GPR stimulation was revealed. Prolonged plateau potentials could still be evoked after this treatment. Local application of serotonin (5-HT; 10 microM to 1 mM) mimicked the noncholinergic plateau inducing effects of GPR stimulation in the DG motor neuron. 3. The synergistic action of acetylcholine (ACh) and 5-HT was examined by stimulating the GPR cells at different frequencies (1-20 Hz). The plateau induction was present down to 2 Hz. The time to onset for triggering a plateau during a GPR train was determined by the co-released ACh. 4. The 5-HT-evoked slow depolarization persisted in tetrodotoxin (TTX; 0.1-1 microM), and the DG motor neuron could still produce a plateau potential on brief depolarization in the absence of the spike-generating mechanism. 5. In normal TTX-containing saline, the 5-HT-evoked depolarization was accompanied by a weak and variable decrease in apparent input conductance. After substituting one-half of the extracellular sodium with either Trisma-HCl or choline, the decrease in apparent input conductance became more pronounced. This decrease was converted to an increase in apparent input conductance when extracellular Ca2+ was replaced with Mg2+. 6. Under voltage-clamp conditions, local application of 5-HT caused a slow inward current of prolonged duration in DG. The current versus voltage relationship had an inverted U-shape with no apparent reversal potential in the entire voltage range investigated (-90 to -5 mV). The 5-HT-induced changes in input conductance showed a complex voltage dependence, with a conductance decrease from moderately depolarized voltages. 7. Extracellular Cs+ (2- 4 mM) caused the DG to hyperpolarize 2-4 mV from rest, whereas lowering extracellular Ca2+ caused it to depolarize 7-15 mV. The combined action of low extracellular Ca2+ and 2-4 mM Cs+ caused an almost complete block of the slow 5-HT-evoked depolarization.(ABSTRACT TRUNCATED AT 400 WORDS)J Neurophysiol 1992682m 485-9592407594&Kiehn, O. Harris-Warrick, R. M.5-HT modulation of hyperpolarization-activated inward current and calcium-dependent outward current in a crustacean motor neuronAnimal Barium/pharmacology Calcium Channels/*drug effects Cesium/pharmacology Crabs/*physiology Ganglia/cytology/drug effects Ion Channels/*drug effects Membrane Potentials/drug effects/physiology Motor Neurons/*drug effects Neural Conduction/drug effects Serotonin/*pharmacology Sodium/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacologyt 1. Serotonergic modulation of a hyperpolarization-activated inward current, Ih, and a calcium-dependent outward current, Io(Ca), was examined in the dorsal gastric (DG) motor neuron, with the use of intracellular recording techniques in an isolated preparation of the crab stomatogastric ganglion (STG). 2. Hyperpolarization of the membrane from rest with maintained current pulses resulted in a slow time-dependent relaxation back toward rest and a depolarizing overshoot after termination of the current pulse. In voltage clamp, hyperpolarizing commands negative to approximately -70 mV caused a slowly developing inward current, Ih, which showed no inactivation. Repolarization back to the holding potential of -50 mV revealed a slow inward tail current. 3. The reversal potential for Ih was approximately -35 mV. Raising extracellular K+ concentration ([K+]o) from 11 to 22 mM enhanced, whereas decreasing extracellular Na+ concentration ([Na+]o) reduced the amplitude of Ih. These results indicate that Ih in DG is carried by both K+ and Na+ ions. 4. Bath application of serotonin (5- HT; 10 microM) caused a marked increase in the amplitude of Ih through its active voltage ranges. 5. The time course of activation of Ih was well fitted by a single exponential function and strongly voltage dependent. 5-HT increased the rate of activation of Ih. 5-HT also slowed the rate of deactivation of the Ih tail on repolarization to -50 mV. 6. The activation curve for the conductance (Gh) underlying Ih was obtained by analyzing tail currents. 5-HT shifted the half activation for Gh from approximately -105 mV in control to -95 mV, resulting in an increase in the amplitude of Gh active at rest. 7. Two to 4 mM Cs+ abolished Ih, whereas barium (200 microM to 2 mM) had only weak suppressing effects on Ih. Concomitantly, Cs+ also blocked the 5-HT- induced inward current and conductance increase seen at voltages negative to rest. In current clamp, Cs+ caused DG to hyperpolarize 3-4 mV from rest, suggesting that Ih is partially active at rest and contributes to the resting membrane potential. 8. Depolarizing voltage commands from a holding potential of -50 mV resulted in a total outward current (Io) with an initial transient component and a sustained steady- state component. Application of 5-HT reduced both the transient and sustained components of Io. 9. Io was reduced by 10-20 mM tetraethylammonium (TEA), suggesting that it is primarily a K+ current.(ABSTRACT TRUNCATED AT 400 WORDS)J Neurophysiol 1992682496-508 lItYFMRFamide/*physiologyForskolin/*pharmacology0-Forskolin/analogs & derivatives/*pharmacology GABA Agonists/pharmacology GABA Antagonists/pharmacologyGABA/*analysis GABA/*metabolism/pharmacologyGABA/*pharmacologyGABA/*physiology GABA/analysisGABA/metabolismGABA/pharmacologyGABA/physiology40gamma-Aminobutyric Acid/*metabolism/pharmacology83Ganglia, Autonomic/*anatomy & histology/*physiology$Ganglia, Autonomic/*physiology0+Ganglia, Autonomic/cytology/*ultrastructure Ganglia, Autonomic/physiologyGanglia, Invertebrate$ Ganglia, Invertebrate/*chemistry4/Ganglia, Invertebrate/*chemistry/ultrastructure(#Ganglia, Invertebrate/*drug effects4.Ganglia, Invertebrate/*drug effects/metabolism4.Ganglia, Invertebrate/*drug effects/physiology$!Ganglia, Invertebrate/*metabolism0,Ganglia, Invertebrate/*metabolism/physiology$!Ganglia, Invertebrate/*physiologyD>Ganglia, Invertebrate/anatomy & histology/*cytology/physiology85Ganglia, Invertebrate/anatomy & histology/*physiology$Ganglia, Invertebrate/chemistry@=Ganglia, Invertebrate/chemistry/cytology/growth & development83Ganglia, Invertebrate/chemistry/cytology/physiology$Ganglia, Invertebrate/cytology0,Ganglia, Invertebrate/cytology/*drug effects0*Ganglia, Invertebrate/cytology/*metabolism0*Ganglia, Invertebrate/cytology/*physiology4.Ganglia, Invertebrate/cytology/*ultrastructure<7Ganglia, Invertebrate/cytology/drug effects/*metabolism<7Ganglia, Invertebrate/cytology/drug effects/*physiologyHBGanglia, Invertebrate/cytology/drug effects/immunology/*metabolism<6Ganglia, Invertebrate/cytology/drug effects/metabolism85Ganglia, Invertebrate/cytology/embryology/*metabolism,)Ganglia, Invertebrate/cytology/physiology("Ganglia, Invertebrate/drug effects4.Ganglia, Invertebrate/drug effects/*metabolism<9Ganglia, Invertebrate/drug effects/*metabolism/physiologyHBGanglia, Invertebrate/drug effects/enzymology/growth & development<8Ganglia, Invertebrate/drug effects/metabolism/physiology0-Ganglia, Invertebrate/drug effects/physiologyDAGanglia, Invertebrate/embryology/growth & development/*physiology0+Ganglia, Invertebrate/embryology/physiology<6Ganglia, Invertebrate/enzymology/immunology/metabolism<6Ganglia, Invertebrate/growth & development/*physiology$ Ganglia, Invertebrate/metabolism40Ganglia, Invertebrate/metabolism/*ultrastructure$ Ganglia, Invertebrate/physiology4/Ganglia, Invertebrate/physiology/ultrastructure$ Ganglia, Sympathetic/*physiology Ganglia/*analysis/metabolismGanglia/*chemistryGanglia/*cytology,)Ganglia/*cytology/drug effects/physiology Ganglia/*cytology/physiologyGanglia/*drug effects0+Ganglia/*drug effects/embryology/physiology$ Ganglia/*drug effects/metabolismGanglia/*physiology("Ganglia/*physiology/ultrastructure84Ganglia/anatomy & histology/*drug effects/physiology,'Ganglia/anatomy & histology/*physiology4/Ganglia/anatomy & histology/cytology/physiology Ganglia/chemistry/cytologyGanglia/cytology,)Ganglia/cytology/*drug effects/physiology Ganglia/cytology/*physiology Ganglia/cytology/drug effects,)Ganglia/cytology/drug effects/*physiology Ganglia/cytology/physiology$ Ganglia/drug effects/*physiology0+Ganglia/drug effects/metabolism/*physiologyGanglia/enzymologyGanglia/physiology("Ganglia/physiology/*ultrastructure$ Ganglionic Blockers/pharmacology(%Gap Junctions/drug effects/metabolism,'Gap Junctions/physiology/ultrastructure,(Gastric Emptying/drug effects/physiology Gastric Emptying/physiology("Gastrins/*isolation & purification 94132889*#Meyrand, P. Simmers, J. Moulins, M.n|vDynamic construction of a neural network from multiple pattern generators in the lobster stomatogastric nervous systemd^Animal Axonal Transport Axons/physiology Digestive System/innervation Electric Stimulation In Vitro Lobsters Models, Neurological Motor Neurons/physiology Muscle, Smooth/innervation Nerve Net/*physiology Nervous System/anatomy & histology/*physiology *Nervous System Physiology Neurons/*physiology Neurons, Afferent/physiology Support, Non-U.S. Gov'tIn the stomatogastric nervous system (STNS) of the lobster Homarus gammarus, the rhythmic discharge of a pair of identified modulatory neurons (PS cells) is able to construct de novo a functional network from neurons otherwise belonging to other functional networks. The PS interneurons are electrically coupled and possess endogenous oscillatory properties that can be activated synaptically by stimulation of an identified sensory pathway. PS neurons themselves project synaptically onto the three major neural networks (esophageal, gastric mill, and pyloric) of the STNS. When a PS is rhythmically active in vitro, either spontaneously (rarely) or in response to direct stimulation, it dramatically restructures the otherwise independent activity patterns of all three target networks. This functional reconfiguration elicited by a single cell does not rely on changes in neuronal allegiance to pre-existing circuits, or on a simple merger of these different circuits. Rather, PS is responsible for the creation of an entirely new motor rhythm in that, via its widespread synaptic connections, the interneuron is able to subjugate the ongoing activity of the three STNS circuits and selectively appropriate individual elements to its own intrinsic rhythm. In addition, PS excites motor neurons that innervate dilator muscles of a valve situated between the esophagus and the stomach. The reorganization of the regional foregut motor rhythms by the interneuron is therefore coordinated to the opening of this valve, which itself carries sensory receptors that have been found to activate bursting in PS. Our data suggest that the role of PS in massively restructuring stomatogastric output is to generate a unique motor pattern appropriate for swallowing-like behavior. In a wider context, moreover, the results demonstrate that a neural network may not exist as a predefined entity within the CNS, but may be dynamically assembled according to changing behavioral circumstances. J Neurosci 1994142h 630-44*#Meyrand, P. Simmers, J. Moulins, M. 1994JCModulation and specification of behavior at the small circuit level $Greenspan, R.J. Kyriacou, C.P.60Flexibility and Constraint in Behavioral Systems New York John Wiley & Sons165-176u%#$" rZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11165800?B;Kiehn, O. Kjaerulff, O. Tresch, M. C. Harris-Warrick, R. M.bzContributions of intrinsic motor neuron properties to the production of rhythmic motor output in the mammalian spinal cord.(Animal Anterior Horn Cells/drug effects/*growth & development/physiology Gap Junctions/drug effects/metabolism Ion Channels/drug effects/metabolism Membrane Potentials/drug effects/*physiology Movement/*physiology Neural Inhibition/drug effects/physiology Periodicity Rats Support, Non-U.S. Gov'tXRMotor neurons are endowed with intrinsic and conditional membrane properties that may shape the final motor output. In the first half of this paper we present data on the contribution of I(h), a hyperpolarization-activated inward cation current, to phase-transition in motor neurons during rhythmic firing. Motor neurons were recorded intracellularly during locomotion induced with a mixture of N-methyl-D- aspartate (NMDA) and serotonin, after pharmacological blockade of I(h). I(h) was then replaced by using dynamic clamp, a computer program that allows artificial conductances to be inserted into real neurons. I(h) was simulated with biophysical parameters determined in voltage clamp experiments. The data showed that electronic replacement of the native I(h) caused a depolarization of the average membrane potential, a phase- advance of the locomotor drive potential, and increased motor neuron spiking. Introducing an artificial leak conductance could mimic all of these effects. The observed effects on phase-advance and firing, therefore, seem to be secondary to the tonic depolarization; i.e., I(h) acts as a tonic leak conductance during locomotion. In the second half of this paper we discuss recent data showing that the neonatal rat spinal cord can produce a stable motor rhythm in the absence of spike activity in premotor interneuronal networks. These coordinated motor neuron oscillations are dependent on NMDA-evoked pacemaker properties, which are synchronized across gap junctions. We discuss the functional relevance for such coordinated oscillations in immature and mature spinal motor systems.'~Section of Neurophysiology, Department of Medical Physiology, University of Copenhagen, Copenhagen, Denmark. O.Kiehn@mfi.ku.dk11165800Brain Res Bull 2000535649-59.97062767Kilman, V. L. Marder, E.ZSUltrastructure of the stomatogastric ganglion neuropil of the crab, Cancer borealisAnimal Axons/physiology/ultrastructure Cell Count Crabs/*physiology Extracellular Space/metabolism Ganglia, Invertebrate/cytology/*ultrastructure Gap Junctions/physiology/ultrastructure GABA/metabolism Immunohistochemistry Lanthanum/metabolism Male Microscopy, Electron Neuroglia/ultrastructure Neurons/physiology/*ultrastructure Oligopeptides/metabolism Plastic Embedding Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/physiology/ultrastructure Tannic Acide The stomatogastric ganglion (STG) of the crab, Cancer borealis, contains the neural networks responsible for rhythmic pattern generation of the foregut. Neuron counts indicate that the STG of C. borealis has 25-26 neurons, 4-5 fewer than that found in lobsters. We describe the ultrastructural features of the ganglion by focusing on those that may be involved in storage, release, or range of action of peptide modulators, including a lacunar system and multiple types of intercellular junctions. In the neuropil, we identify five synaptic profile classes that contain the invertebrate presynaptic apparatus (dense bars, small clear vesicles), two of which also contain dense core (modulator-containing) vesicles. These latter two are comprised of multiple immunocytochemical classes that are not easily distinguished by structural criteria. In addition, we find neurohemal-like profiles that contain primarily dense core vesicles. Our finding that multiple profile types in the STG possess modulator-containing vesicles coincides with immunocytochemical results better than do previous ultrastructural studies that report only one such profile type. We show that a single modulatory input, stomatogastric nerve axon 1, makes only classical synapses and not neurohemal-like profiles, although some modulators are found in both these profile types. These data provide the groundwork for understanding the architecture of modulatory input- target interactions and suggest ways that the specificity of modulatory effects within a complex neuropil may be attained. J Comp Neurol 1996 3743 362-75ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10340509dVOKilman, V. Fenelon, V. S. Richards, K. S. Thirumalai, V. Meyrand, P. Marder, E.tSequential developmental acquisition of cotransmitters in identified sensory neurons of the stomatogastric nervous system of the lobsters, Homarus americanus and Homarus gammarus Animal Digestive System/innervation Ganglia, Invertebrate/*chemistry Immunohistochemistry Lobsters/anatomy & histology/*chemistry Microscopy, Confocal Neurons, Afferent/*chemistry Neuropeptides/analysis Neurotransmitters/*analysis Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.We studied the developmental acquisition of three of the cotransmitters found in the gastropyloric receptor (GPR) neurons of the stomatogastric nervous systems of the lobsters Homarus americanus and Homarus gammarus. By using wholemount immunocytochemistry and confocal microscopy, we examined the distribution of serotonin-like, allatostatin-like, and FLRF(NH2)-like immunoreactivities within the stomatogastric nervous system of embryonic, larval, juvenile, and adult animals. The GPR neurons are peripheral sensory neurons that send proprioceptive information to the stomatogastric and commissural ganglia. In H. americanus, GPR neurons of the adult contain serotonin- like, allatostatin-like, and Phe-Leu-Arg-Phe-amide (FLRF(NH2))-like immunoreactivities. In the stomatogastric ganglion (STG) of the adult H. americanus and H. gammarus, all of the serotonin-like and allatostatin-like immunoreactivity colocalizes in neuropil processes that are derived exclusively from ramifications of the GPR neurons. In both species, FLRF(NH2)-like immunoreactivity was detected in the STG neuropil by 50% of embryonic development (E50). Allatostatin-like immunoreactivity was visible first in the STG at approximately E70-E80. In contrast, serotonin staining was not clearly visible until larval stage I (LI) in H. gammarus and until LII or LIII in H. americanus. These data indicate that there is a sequential acquisition of the cotransmitters of the GPR neurons.'b\Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454, USA.10340509 J Comp Neurol 1999 4083318-34.ztKim, M. Baro, D.J. Lanning, C.C. Doshi, M. Farnham, J. Moskowitz, H.S. Peck, J.H. Olivera, B.M. Harris-Warrick, R.M. 1997RLAlternative splicing in the pore-forming region of shaker potassium channels J Neurosci17 8213-8224e( '0& 76192974 King, D. G.yrkOrganization of crustacean neuropil. I. Patterns of synaptic connections in lobster stomatogastric ganglion^XAnimal Autonomic Fibers, Postganglionic/ultrastructure Autonomic Fibers, Preganglionic/ultrastructure Ganglia, Autonomic/cytology/*ultrastructure *Lobsters Mouth/innervation Neuroglia/ultrastructure Neurons/ultrastructure Stomach/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*ultrastructure Synaptic VesiclesThe stomatogastric ganglion of the lobster consists of about thiry neurons, mainly large monopolar cells, which have been well characterized physiologically. This paper presents an anatomical description of this ganglion, emphasizing synaptic connections in the neuropil. The neuron cell bodies are located on the dorsal surface of the ganglion. They send processes into the underlying neuropil mass. The neuropil is differentiated into two regions: a core of coarse neuropil consists of large heavily ensheathed processes; a surrounding region of fine-textured synaptic neuropil consists of smaller unsheather processes. Synapses are found only in synaptic neuropil, not in the core of coarse neuropil. Synaptic contacts, about one million in the entire neuropil, are easily recognized by a set of criteria including presynaptic vesicles and pre- and postsynaptic membrane specializations. Most synaptic contacts invole at least three neural processes, usually one pre- and two postsynaptic elements. Synapses are clustered onto irregular swellings or varicosities on neural processes. These varicosities make both pre- and postsynaptic contacts. Three differenty types of presynaptic profile are recognized. Pyloric dilator, ventricular dilator and lateral posterior gastric neurons belong to type A with clear irregular synaptic vesicles. Lateral pyloric, pyloric, anterior median and dorsal gastric neurons belong to type B with larger clear round vesicles. Many unidentified fibres, presumably stomatogastric nerve afferents, blong to type C with both small clear irregular vesicles and also large dense-core vesicles. The synaptic vesicle types are tentatively correlated with neurotransmitter: type A with acetylcholine, type B with an unknown transmitter, possibly glutamate, and type C with dopamine. The distribution of synaptic contacts on the processes of identified neurons reconstructed from serial section is presented in the following paper. J Neurocytol 197652 207-3776192975 King, D. G.dOrganization of crustacean neuropil. II. Distribution of synaptic contacts on identified motor neurons in lobster stomatogastric ganglionoAnimal Ganglia, Autonomic/cytology/*ultrastructure *Lobsters Motor Neurons/*ultrastructure Mouth/innervation Neuroglia/ultrastructure Stomach/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology/*ultrastructure Synaptic Transmissionp0)Identified neurons in the stomatogastric ganglion of the lobster were examined and reconstructed by serial section electron microscopy. Each motor neuron consists of a soma, a primary process leading directly from the soma to the motor axon which leaves the ganglion, and a group of secondary processes which branch from the primary process and ramify within the neuropil. Synapses are found only on small processes in the synaptic neuropil, never on the primary processes or on larger secondary processes in the coarse neuropil. Nearly every secondary process of every neuron examined makes both pre- and postsynaptic contacts. Hence these neurons are not polarized into distinct pre- and postsynaptic regions but have both input and output distributed over each of the secondary processes in the neuropil. The conncetion between a specific pair of neurons is also distributed over several branches of both the pre- and the postsynaptic neurons. The restriction of synapses to the more distal portions of the secondary processes suggests that no single contact or localized group of contacts can exert an overrriding influence on the neuron by virtue of an especially advantageous position. The close proximity of input and output on most secondary processes suggests that synaptic input may be capable of directly influencing output without the intervention of action potentials. The distribution of specific synapses over several branches of both pre- and postsynaptic neurons suggests that each neuron functions as a whole without differentiation into specialized branches. J Neurocytol 197652 239-66:3Kloppenburg, P. Levini, R. M. Harris-Warrick, R. M.bDopamine modulates two potassium currents and inhibits the intrinsic firing properties of an identified motor neuron in a central pattern generator networktAction Potentials/physiology Animal Central Nervous System/cytology/*physiology Dopamine/*physiology Electric Stimulation Electrophysiology In Vitro Lobsters/*physiology Membrane Potentials/physiology Motor Neurons/*physiology Patch-Clamp Techniques Potassium Channels/*physiology Pylorus/innervation/physiology Stomach/innervation/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologyThe two pyloric dilator (PD) neurons are components [along with the anterior burster (AB) neuron] of the pacemaker group of the pyloric network in the stomatogastric ganglion of the spiny lobster Panulirus interruptus. Dopamine (DA) modifies the motor pattern generated by the pyloric network, in part by exciting or inhibiting different neurons. DA inhibits the PD neuron by hyperpolarizing it and reducing its rate of firing action potentials, which leads to a phase delay of PD relative to the electrically coupled AB and a reduction in the pyloric cycle frequency. In synaptically isolated PD neurons, DA slows the rate of recovery to spike after hyperpolarization. The latency from a hyperpolarizing prestep to the first action potential is increased, and the action potential frequency as well as the total number of action potentials are decreased. When a brief (1 s) puff of DA is applied to a synaptically isolated, voltage-clamped PD neuron, a small voltage- dependent outward current is evoked, accompanied by an increase in membrane conductance. These responses are occluded by the combined presence of the potassium channel blockers 4-aminopyridine and tetraethylammonium. In voltage-clamped PD neurons, DA enhances the maximal conductance of a voltage-sensitive transient potassium current (IA) and shifts its Vact to more negative potentials without affecting its Vinact. This enlarges the "window current" between the voltage activation and inactivation curves, increasing the tonically active IA near the resting potential and causing the cell to hyperpolarize. Thus DA's effect is to enhance both the transient and resting K+ currents by modulating the same channels. In addition, DA enhances the amplitude of a calcium-dependent potassium current (IO(Ca)), but has no effect on a sustained potassium current (IK(V)). These results suggest that DA hyperpolarizes and phase delays the activity of the PD neurons at least in part by modulating their intrinsic postinhibitory recovery properties. This modulation appears to be mediated in part by an increase of IA and IO(Ca). IA appears to be a common target of DA action in the pyloric network, but it can be enhanced or decreased in different ways by DA in different neurons.'rkSection of Neurobiology and Behavior, Seeley G. Mudd Hall, Cornell University, Ithaca, New York 14853, USA.9914264http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9914264 http://jn.physiology.org/cgi/content/full/81/1/29J Neurophysiol 1999811 29-38.5:4 31l2d./ Kushner, P.D. Barker, D.L. 1983voA neurochemical description of the dopaminergic innervation of the stomatogastric ganglion of the spiny lobster J NeurobiolD14 17-28( Kushner, P.D. 1987HACocaine activates the motor output of the stomatogastric ganglion "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag)304-306g67083106 Larimer, J. L. Kennedy, D.HAVisceral afferent signals in the crayfish stomatogastric ganglionlAnimal Crustacea/*physiology Electric Stimulation Electrophysiology Ganglia, Autonomic/*anatomy & histology/*physiology Intestines/innervation Motor Neurons Stomach/innervation J Exp Biol 1966442e 345-54XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=2469179Larimer, J. L.>7The command hypothesis: a new view using an old example tnAnimal Behavior, Animal/*physiology Crustacea/*physiology Interneurons/*physiology Support, U.S. Gov't, P.H.S.2469179sTrends Neurosci, 19881111506-10.cZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10604471m.(Le Feuvre, Y. Fenelon, V. S. Meyrand, P.ZTCentral inputs mask multiple adult neural networks within a single embryonic networkAnimal Ganglia, Invertebrate/embryology/physiology Lobsters/anatomy & histology/*embryology/physiology Nerve Net/*embryology/physiology Nervous System/embryology Neurons/physiologyIt is usually assumed that, after construction of basic network architecture in embryos, immature networks undergo progressive maturation to acquire their adult properties. We examine this assumption in the context of the lobster stomatogastric nervous system. In the lobster, the neuronal population that will form this system is at first orgnanized into a single embryonic network that generates a single rhythmic pattern. The system then splits into different functional adult networks controlled by central descending systems; these adult networks produce multiple motor programmes, distinctively different from the single output of the embryonic network. We show here that the single embryonic network can produce multiple adult-like programmes. This occurs after the embryonic network is silenced by removal of central inputs, then pharmacologically stimulated to restore rhythmicity. Furthermore, restoration of the flow of descending information reversed the adult-like pattern to an embryonic pattern. This indicates that the embryonic network possesses the ability to express adult-like network characteristics, but descending information prevents it from doing so. Functional adult networks may therefore not necessarily be derived from progressive ontogenetic changes in networks themselves, but may result from maturation of descending systems that unmask preexisting adult networks in an embryonic system.y'jcLaboratoire de Neurobiologie des Reseaux, CNRS et Universite Bordeaux I, UMR 5816, Talence, France. 10604471 Nature 1999 402f 6762 660-4..(Le Feuvre, Y. Fenelon, V. S. Meyrand, P.zOntogeny of modulatory inputs to motor networks: early established projection and progressive neurotransmitter acquisitionAnimal Digestive System/cytology/embryology/innervation Dyes Efferent Pathways/cytology/embryology/*metabolism Female GABA/metabolism Ganglia, Invertebrate/cytology/embryology/*metabolism Histamine/metabolism Immunohistochemistry Lobsters Male Motor Neurons/cytology/*metabolism Nerve Net/cytology/embryology/*metabolism Neuronal Plasticity/physiology Neurotransmitters/*metabolism Oligopeptides/metabolism Phenotype Support, Non-U.S. Gov'tModulatory information plays a key role in the expression and the ontogeny of motor networks. Many developmental studies suggest that the acquisition of adult properties by immature networks involves their progressive innervation by modulatory input neurons. Using the stomatogastric nervous system of the European lobster Homarus gammarus, we show that contrary to this assumption, the known population of projection neurons to motor networks, as revealed by retrograde dye migration, is established early in embryonic development. Moreover, these neurons display a large heterogeneity in the chronology of acquisition of their full adult neurotransmitter phenotype. We performed retrograde dye migration to compare the neuronal population projecting to motor networks located in the stomatogastric ganglion in the embryo and adult. We show that this neuronal population is quantitatively established at developmental stage 65%, and each identified projection neuron displays the same axon projection pattern in the adult and the embryo. We then combined retrograde dye migration with FLRFamide-like, histamine, and GABA immunocytochemistry to characterize the chronology of neurotransmitter expression in individual identified projection neurons. We show that this early established population of projection neurons gradually acquires its neurotransmitter phenotype complement. This study indicates that (1) the basic architecture of the known population of projection inputs to a target network is established early in development and (2) ontogenetic plasticity may depend on changes in neurotransmitter phenotype expression within preexisting neurons rather than in the addition of new projection neurons or fibers.'Laboratoire de Neurobiologie des Reseaux, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5816, Universite Bordeaux I, 33405 Talence cedex, France. y.lefeuvre@lnr.u-bordeaux.fr11160402http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11160402 http://www.jneurosci.org/cgi/content/full/21/4/1313 http://www.jneurosci.org/cgi/content/abstract/21/4/1313 J Neurosci 20012141313-26.93206139,%LeMasson, G. Marder, E. Abbott, L. F.uD>Activity-dependent regulation of conductances in model neurons81Animal Calcium/*metabolism/pharmacology Electric Conductivity Electric Stimulation Feedback *Models, Biological Neurons/drug effects/*physiology Potassium/metabolism/pharmacology Second Messenger Systems Sodium/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S..JCNeurons maintain their electrical activity patterns despite channel turnover, cell growth, and variable extracellular conditions. A model is presented in which maximal conductances of ionic currents depend on the intracellular concentration of calcium ions and so, indirectly, on activity. Model neurons with activity-dependent maximal conductances modify their conductances to maintain a given behavior when perturbed. Moreover, neurons that are described by identical sets of equations can develop different properties in response to different patterns of presynaptic activity.Science 1993 259 5103 1915-7-0,+ h*6)F?Kloppenburg, P. Zipfel, W. R. Webb, W. W. Harris-Warrick, R. M.eHighly localized Ca(2+) accumulation revealed by multiphoton microscopy in an identified motoneuron and its modulation by dopamineAnimal Calcium/*metabolism Dopamine/*pharmacology Lobsters Microscopy Motor Neurons/drug effects/*metabolism Neuropil/metabolism Support, U.S. Gov't, P.H.S. Synaptic TransmissionCalcium is essential for synaptic transmission and the control of the intrinsic firing properties of neurons; this makes Ca(2+) channels a prime target for neuromodulators. A combination of multiphoton microscopy and voltage-clamp recording was used to determine the localization of voltage-dependent Ca(2+) accumulation in the two pyloric dilator (PD) neurons of the pyloric network in the spiny lobster, Panulirus interruptus, and its modulation by dopamine. We monitored [Ca(2+)](i) in fine distal branches in the neuropil >350 microm below the surface of the ganglion during controlled voltage steps in voltage clamp. Ca(2+) accumulation originated mostly from small, fairly rare, spatially restricted varicosities on distal neuritic arborizations. Ca(2+) diffused from these point sources into adjacent regions. Varicosities with similar morphology in the PD neuron have been shown previously to be sites of synaptic contacts. We have demonstrated in earlier studies that dopamine inhibits activity and greatly reduces synaptic transmission from the PD neuron. In approximately 60% of the varicosities, the voltage-activated Ca(2+) accumulation was reduced by exogenous dopamine (DA) (10(-4) M). DA decreased the peak amplitude of Ca(2+) accumulation but had no effect on the rise and decay time. We conclude that DA reduces chemical synaptic transmission from the PD neurons at least in part by decreasing Ca(2+) entry at neurotransmitter release sites.i'Department of Neurobiology and Behavior, Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA. pk29@cornell.edui10729332http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10729332 http://www.jneurosci.org/cgi/content/full/20/7/2523 http://www.jneurosci.org/cgi/content/abstract/20/7/2523e J Neurosci 2000207 2523-33.0)Kopell, N. Abbott, L. F. Soto-Trevino, C.1 1998XROn the behavior of a neural oscillator electrically coupled to a bistable element Physica D; 121r 3-40367-395.D>Oscillations; Wave form; Bistable element; Electrical coupling,&We study the periodic solutions of a two-cell network consisting of a relaxation oscillator and a bistable element. The aim is to understand how the frequency and wave form of the network depend on the intrinsic properties of the cells and on the strength of the coupling between them. The network equations constitute a fast-slow system; we show that there are four curves of saddle-node points of the fast system whose geometry in parameter space encodes information about the wave form and frequency. These curves give information about the value of the variables at which transitions are made between high and low voltage states for either of the elements, and how those transition points in phase space depend on the coupling strength. Furthermore, we develop a new geometric method to construct the curves of saddle-nodes from families of curves associated with the equations for each of the two cells. The construction allows one to see how changes in either of the elements affects the wave form of the network output. The analysis also shows that the network can produce unintuitive behavior. For example, though electric coupling may keep the network pinned longer at a higher or lower voltage level than the uncoupled oscillator, larger values of the coupling strength may be less effective at this pinning.D>Krenz, W. D. Nguyen, D. Perez-Acevedo, N. L. Selverston, A. I.~Group I, II, and III mGluR compounds affect rhythm generation in the gastric circuit of the crustacean stomatogastric ganglionAlanine/analogs & derivatives/pharmacology Amino Acids, Dicarboxylic/pharmacology Animal Cycloleucine/analogs & derivatives/pharmacology Dose-Response Relationship, Drug Excitatory Amino Acid Agonists/pharmacology Excitatory Amino Acid Antagonists/pharmacology Female Ganglia, Invertebrate/*drug effects In Vitro Lobsters/*physiology Male Methoxyhydroxyphenylglycol/analogs & derivatives/pharmacology Motor Neurons/drug effects/physiology Nerve Net/*physiology Quisqualic Acid/pharmacology Receptors, Metabotropic Glutamate/agonists/antagonists & inhibitors/*drug effects Stomach/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.We have studied the effects of group I, II, and III metabotropic glutamate receptor (mGluR) agonists on rhythm generation by the gastric circuit of the stomatogastric ganglion (STG) of the Caribbean spiny lobster Panulirus argus. All mGluR agonists and some antagonists we tested in this study had clear and distinct effects on gastric rhythm generation when superfused over combined oscillating or blocked silent STG preparations. A consistent difference between group I agonists and group II and III agonists was that group I agonists acted excitatory. The group I-specific agonists L-quisqualic acid and (S)-3,5- dihydroxyphenylglycine, as well as the nonspecific agonist (1S,3R)-1- aminocyclopentane-1, 3-dicarboxylic acid accelerated ongoing rhythms and could induce gastric rhythms in silent preparations. The group II agonist (2S,1'S, 2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) and the group III agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4) slowed down or completely blocked ongoing gastric rhythms and were without detectable effect on silent preparations. The action of L-CCG-I was blocked partially by the group-II-specific antagonist, (RS)-1-amino-5- phosphonoindan-1-carboxylic acid [(RS)APICA], and the group-III- specific antagonist (RS)-alpha-methyl-4-phosphonophenylglycine completely blocked the action of L-AP4. Besides its antagonistic action, the group-II-specific antagonist (RS)APICA had a remarkably strong apparent inverse agonist action when applied alone on oscillating preparations. The action of all drugs was dose dependent and reversible, although recovery was not always complete. In our experiments, the effects of none of the mGluR-specific agonists were antagonized or amplified by the N-methyl-D-aspartate (NMDA)-receptor- specific antagonist D(-)-2-amino-5-phosphonopentanoic acid, excluding the contamination of responses to mGluR agonists by nonspecific cross- reactivity with NMDA receptors. Picrotoxin did not prevent the inhibitory action of L-CCG-I and L-AP4. We conclude that mGluRs, probably similar to those belonging to groups I, II, and III described in mammals, may play a role as modulators of gastric circuit rhythm generation in vivo.'vpInstitute of Neurobiology, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico 00901, USA.10712449http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10712449 http://www.jn.org/cgi/content/full/83/3/1188 http://www.jn.org/cgi/content/abstract/83/3/1188J Neurophysiol 2000833 1188-201. Kunze, J.C. Anderson, D.T. 1976Functional morphology of the mouthparts and gastric mill in the hermit crabs Clibanaruis taeniatus (Milne Edwards), Clibanarius virescens (Karuss), Paguristes sqamosus McCullock and Dardanus setifer (Milne Edwards) (Anomura: Paguridae) MbtAust J Mar Freshw ResB30683-722 "Kushner, P.D. Maynard, E.A. 1977\VLocalization of monamine fluorescence in the stomatogastric nervous system of lobsters Brain Res 129 13-28 Kushner, P.D. 1979\ULocation of interganglionic neurons in the stomatogastric system of the spiny lobster J Neurocytol8 81-94LKJI12840081904  2003 Oct/Episodic bouts of activity accompany recovery of rhythmic output by a neuromodulator- and activity-deprived adult neural network2720-30tThe pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis, slows or stops when descending modulatory inputs are acutely removed. However, the rhythm spontaneously resumes after one or more days in the absence of neuromodulatory input. We recorded continuously for days to characterize quantitatively this recovery process. Activity bouts lasting 40-900 s began several hours after removal of neuromodulatory input and were followed by stable rhythm recovery after 1-4 days. Bout duration was not related to the intervals (0.3-800 min) between bouts. During an individual bout, the frequency rapidly increased and then decreased more slowly. Photoablation of back-filled neuromodulatory terminals in the stomatogastric ganglion (STG) neuropil had no effect on activity bouts or recovery, suggesting that these processes are intrinsic to the STG neuronal network. After removal of neuromodulatory input, the phase relationships of the components of the triphasic pyloric rhythm were altered, and then over time the phase relationships moved toward their control values. Although at low pyloric rhythm frequency the phase relationships among pyloric network neurons depended on frequency, the changes in frequency during recovery did not completely account for the change in phase seen after rhythm recovery. We suggest that activity bouts represent underlying mechanisms controlling the restructuring of the pyloric network to allow resumption of an appropriate output after removal of neuromodulatory input. 'F@Volen Center, Brandeis University, Waltham, Massachusetts 02454.PJLuther, J. A. Robie, A. A. Yarotsky, J. Reina, C. Marder, E. Golowasch, J.("22896630 0022-3077 Journal ArticleJ Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12840081h12526777371 2003 Jan 9.F?Activity-independent homeostasis in rhythmically active neuronsp 109-20The shal gene encodes the transient potassium current (I(A)) in neurons of the lobster stomatogastric ganglion. Overexpression of Shal by RNA injection into neurons produces a large increase in I(A), but surprisingly little change in the neuron's firing properties. Accompanying the increase in I(A) is a dramatic and linearly correlated increase in the hyperpolarization-activated inward current (I(h)). The enhanced I(h) electrophysiologically compensates for the enhanced I(A), since pharmacological blockade of I(h) uncovers the physiological effects of the increased I(A). Expression of a nonfunctional mutant Shal also induces a large increase in I(h), demonstrating a novel activity-independent coupling between the Shal protein and I(h) enhancement. Since I(A) and I(h) influence neuronal activity in opposite directions, our results suggest a selective coregulation of these channels as a mechanism for constraining cell activity within appropriate physiological parameters.'ZSDepartment of Neurobiology and Behavior, Cornell University, 14853, Ithaca, NY, USAD=MacLean, J. N. Zhang, Y. Johnson, B. R. Harris-Warrick, R. M.("22415622 0896-6273 Journal Article Neuronlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12526777.(Macmillan, D.L. Wales, W. Laverack, M.S. 1976XMandibular movement and their control in Homarus gammarus. III. Effects of load changes)9J Comp Physiol 106t207-221t145735352329 2003 Oct 22ZTShort-term dynamics of a mixed chemical and electrical synapse in a rhythmic network9557-64NHIn the rhythmically active pyloric circuit of the spiny lobster, the synapse between the lateral pyloric (LP) neuron and pyloric constrictor (PY) neuron has an inhibitory depressing chemical and an electrical component. To understand how the dynamics of the LP-->PY synapse affect the relative firing times between these two neurons in an ongoing rhythm, we characterized the dynamics of the LP-->PY synapse after a pharmacological block of ongoing activity. When a train of voltage pulses was applied to the voltage-clamped LP neuron, the inhibitory chemical component of the postsynaptic potential (PSP) in the PY neuron rapidly depressed. Thus, after the first few pulses, the PSP was either hyperpolarizing or depolarizing, depending on the interpulse duration, with shorter interpulse durations producing depolarizing PSPs. To characterize the synaptic response during rhythmic activity, we played back prerecorded realistic waveforms in the voltage-clamped LP neuron. After an initial transient, the resulting PSP in PY was always depolarizing, suggesting that in an ongoing rhythm, the electrical component of the synapse is dominant. However, our results indicate that the chemical component of the synapse acts to delay the peak time of the PSP and to reduce its amplitude, and that these effects become more important at slower cycle periods.'jdCenter for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA.$Mamiya, A. Manor, Y. Nadim, F. 1529-2401 Journal Article J Neurosci~Action Potentials/physiology Animals Electric Stimulation Excitatory Postsynaptic Potentials/physiology In Vitro Models, Neurological Nerve Net/*physiology Nervous System Physiology Neural Inhibition/physiology Neurons/physiology Palinuridae Patch-Clamp Techniques *Periodicity Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiologylehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14573535:978612676158 118 1. 2003PICalcium signaling components of oscillating invertebrate neurons in vitrog 283-96 We have studied the Ca(2+) dynamics of bursting-spiking neurons in the lobster stomatogastric ganglion. Neurons in this ganglion undergo spontaneous oscillations in membrane voltage with a period of 1-10 s in situ. We found that neurons isolated from the ganglion and filled with the fluorescent calcium indicator Fluo-4 show simultaneous changes of membrane potential and cytoplasmic Ca(2+) concentration ([Ca(2+)](I)). These Ca(2+) signals are highly heterogeneous both in terms of amplitude and time constants. They showed variable spatial distributions with the soma exhibiting low and slow signals, and a region in the process with large and fast signals.Ca(2+) transients in the processes are dependent on external Ca(2+) and can be blocked by Co(2+), but not other, more specific Ca(2+) current blockers. Rather, nifedipine a known Ca(2+) current blocker, affects the distribution of the Ca(2+) signal, which suggests a specific localization of Ca(2+) channels. Although the signal is not absolutely dependent on action potentials, it is greatly reduced when action potentials are blocked by tetrodotoxin. Termination of the signal depends only slightly on Ca(2+) buffering mechanisms such as mitochondria, Ca(2+)/Na(+) and Ca(2+)/H(+) exchangers.We also demonstrate the presence of caffeine-sensitive internal stores in stomatogastric ganglion cells. The store distribution is different but overlaps with the voltage-dependent distribution. The maximal caffeine-activated Ca(2+) signal is in the soma and it is smaller in the processes. Unlike the voltage-activated Ca(2+) signal this signal is not blocked by Co(2+). Nevertheless, the two types of signal interact during caffeine application. This unique spatial separation of two Ca(2+) sources may have important functional implication.u'^XInstitute for Nonlinear Sciences, UCSD, 9500 Gilman Drive, 92093-0402, La Jolla, CA, USA.(Levi, R. Samoilova, M. Selverston, A. I.("22563988 0306-4522 Journal Article Neurosciencelehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12676158rZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11840477 RLLi, L. Pulver, S. R. Kelley, W. P. Thirumalai, V. Sweedler, J. V. Marder, E.rkOrcokinin peptides in developing and adult crustacean stomatogastric nervous systems and pericardial organsnAging/*metabolism Amino Acid Sequence/genetics Animal Crabs/growth & development/*metabolism Electrophysiology Embryo Immunohistochemistry Larva Lobsters/growth & development/*metabolism Molecular Sequence Data Nervous System/growth & development/metabolism Nervous System Physiology Neuropeptides/genetics/*metabolism Peptide Fragments/genetics/metabolism Pericardium/growth & development/*metabolism Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Stomach/*innervation Support, U.S. Gov't, P.H.S. Tissue DistributionThe orcokinins are a family of neuropeptides recently isolated from several crustacean species. We found orcokinin-like immunoreactivity in the stomatogastric nervous systems and pericardial organs of three decapod crustacean species, Homarus americanus, Cancer borealis, and Panulirus interruptus. The neuropil of the stomatogastric ganglion was stained in adults of all three species as well as in embryonic and larval H. americanus. In H. americanus, the somata giving rise to this projection were found in the inferior ventricular nerve. Matrix- assisted laser desorption/ionization mass spectrometry mass profiling and sequencing with postsource decay led to the identification of six different orcokinin family peptides, including those previously described in other decapods and two novel shorter peptides. Application of exogenous [Ala(13)]orcokinin to the stomatogastric ganglion of H. americanus resulted in changes in the pyloric rhythm. Specifically, the number of lateral pyloric (LP) neuron spikes/burst decreased, and the phase of firing of the pyloric neurons was altered. Together, these data indicate that the orcokinins are likely to function as modulators of the crustacean stomatogastric ganglion.'jcDepartment of Chemistry and Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA.11840477 J Comp Neurol 2002 4443227-44.14535947873 2003 Nov6Mass spectrometric investigation of the neuropeptide complement and release in the pericardial organs of the crab, Cancer borealis 642-56The crustacean stomatogastric ganglion (STG) is modulated by both locally released neuroactive compounds and circulating hormones. This study presents mass spectrometric characterization of the complement of peptide hormones present in one of the major neurosecretory structures, the pericardial organs (POs), and the detection of neurohormones released from the POs. Direct peptide profiling of Cancer borealis PO tissues using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) revealed many previously identified peptides, including proctolin, red pigment concentrating hormone (RPCH), crustacean cardioactive peptide (CCAP), several orcokinins, and SDRNFLRFamide. This technique also detected corazonin, a well-known insect hormone, in the POs for the first time. However, most mass spectral peaks did not correspond to previously known peptides. To characterize and identify these novel peptides, we performed MALDI postsource decay (PSD) and electrospray ionization (ESI) MS/MS de novo sequencing of peptides fractionated from PO extracts. We characterized a truncated form of previously identified TNRNFLRFamide, NRNFLRFamide. In addition, we sequenced five other novel peptides sharing a common C-terminus of RYamide from the PO tissue extracts. High K+ depolarization of isolated POs released many peptides present in this tissue, including several of the novel peptides sequenced in the current study.f_Li, L. Kelley, W. P. Billimoria, C. P. Christie, A. E. Pulver, S. R. Sweedler, J. V. Marder, E.("22912917 0022-3042 Journal Article J Neurochemlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14535947 Lingle, C. 1980PIThe sensitivity of decapod foregut muscles to acetylcholine and glutamateJ Comp Physiol 138187-199 Lingle, C. 1981XRThe modulatory action of dopamine on crustacean foregut neuromuscular preparations J Exp Biol94285-299= <83294120 Lingle, C.NHDifferent types of blockade of crustacean acetylcholine-induced currentsAnimal Atropine/pharmacology Carbachol/antagonists & inhibitors Curare/pharmacology Decamethonium Compounds/pharmacology Dose-Response Relationship, Drug Ganglionic Blockers/pharmacology Ion Channels/drug effects Lidocaine/analogs & derivatives/pharmacology Lobsters Membrane Potentials/drug effects Muscles/*drug effects Parasympatholytics/*pharmacology Procaine/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Trimethaphan/pharmacology(!The voltage dependence, concentration dependence, and agonist dependence of blocking and unblocking produced by anticholinergic agents on the ionophoretically activated cholinergic currents of the lobster gastric mill 1 (g.m.1) muscle were examined. Although the ionophoretic technique provides only qualitative information as to blocking mechanisms it is useful in revealing slow components of the blocking action of some drugs. At least two qualitatively different types of voltage-dependent block of the crustacean cholinergic currents were observed. For pempidine, mecamylamine and decamethonium (also chlorisondamine: Lingle, 1983), a slowly developing voltage-dependent block was produced that led to the formation of a stable-blocked state. Recovery from this stable-blocked state is largely dependent on subsequent application of agonist. In contrast, recovery from the voltage-dependent block produced by QX-222, atropine, procaine and curare either proceeds independently of agonist application or occurs too rapidly to be observed by the present methods. Blockade by hexamethonium reveals anomalous voltage dependence, being enhanced over some voltages and relieved with additional hyperpolarization. Blockade by trimetaphan is largely independent of membrane potential except at higher concentrations.J Physiol (Lond) 1983 339 419-3783215236Lingle, C. Auerbach, A.aComparison of excitatory currents activated by different transmitters on crustacean muscle. II. Glutamate-activated currents and comparison with acetylcholine currents present on the same muscle>8Acetylcholine/*physiology Animal Comparative Study Crabs/*physiology Electric Conductivity Electricity Glutamates/*physiology Homeostasis Lobsters/*physiology Muscles/*physiology Neurotransmitters/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologyThe properties of glutamate-activated excitatory currents on the gm6 muscle from the foregut of the spiny lobsters Panulirus argus and interruptus and the crab Cancer borealis were examined using either noise analysis, analysis of synaptic current decays, or slow iontophoretic currents. The properties of acetylcholine currents activated in nonjunctional regions of the gm6 muscle were also examined. At 12 degrees C and -80 mV, the predominant time constant of power spectra from glutamate-activated current noise was approximately 7 ms and the elementary conductance was approximately 34 pS. At 12 degrees C and -80 mV, the predominant time constant of acetylcholine- activated channels was approximately 11 ms with a conductance of approximately 12 pS. Focally recorded glutamatergic extracellular synaptic currents on the gm6 muscle decayed with time constants of approximately 7-8 ms at 12 degrees C and -80 mV. The decay time constant was prolonged e-fold about every 225-mV hyperpolarization in membrane potential. The Q10 of the time constant of the synaptic current decay was approximately 2.6. The voltage dependence of the steady-state conductance increase activated by iontophoretic application of glutamate has the opposite direction of the steady-state conductance activated by cholinergic agonists when compared on the gm6 muscles. The glutamate-activated conductance increase is diminished with hyperpolarization. The properties of the marine crustacean glutamate channels are discussed in relation to glutamate channels in other organisms and to the acetylcholine channels found on the gm6 muscle and the gm1 muscle of the decapod foregut (Lingle and Auerbach, 1983). J Gen Physiol 1983814 571-88u ^l($Chromatography, High Pressure Liquid84241937Marder, E. Eisen, J. S.tmElectrically coupled pacemaker neurons respond differently to same physiological inputs and neurotransmittersZTAnimal Cerebral Ventricles/physiology Dopamine/pharmacology Electric Stimulation Electrophysiology Interneurons/drug effects/physiology Lobsters Motor Neurons/drug effects/physiology Neurotransmitters/*physiology Pilocarpine/pharmacology Pyloric Antrum/*innervation Serotonin/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.& The two pyloric dilator (PD) motor neurons and the single anterior burster (AB) interneuron are electrically coupled and together comprise the pacemaker for the pyloric central pattern generator of the stomatogastric ganglion of the lobster, Panulirus interruptus. Previous work (31) has shown that the AB neuron is an endogenously bursting neuron, while the PD neuron is a conditional burster. In this paper the effects of physiological inputs and neurotransmitters on isolated PD neurons and AB neurons were studied using the lucifer yellow photoinactivation technique (33). Stimulation of the inferior ventricular nerve (IVN) fibers at high frequencies elicits a triphasic response in AB and PD neurons: a rapid excitatory postsynaptic potential (EPSP) followed by a slow inhibitory postsynaptic potential (IPSP), followed by an enhancement of the pacemaker slow-wave depolarizations. Photoinactivation experiments indicate that the enhancement of the slow wave is due primarily to actions of the IVN fibers on the PD neurons but not on the AB neuron. Bath-applied dopamine dramatically alters the motor output of the pyloric system. Photoinactivation experiments show that 10(-4) M dopamine increases the amplitude and frequency of the slow-wave depolarizations recorded in the AB neurons but hyperpolarizes and inhibits the PD neurons. Bath- applied serotonin increases the frequency and amplitude of the slow- wave depolarizations in the AB neuron but has no effect on PD neurons. Pilocarpine, a muscarinic cholinergic agonist, stimulates slow-wave depolarization production in both PD neurons and the AB neuron, but the waveform and frequency of the slow waves elicited are quite different. These results show that although the electrically coupled PD and AB neurons always depolarize synchronously and act together as the pacemaker for the pyloric system, they respond differently to a neuronal input and to several putative neuromodulators. Thus, despite electrical coupling sufficient to ensure synchronous activity, the PD and AB neurons can be modulated independently.J Neurophysiol 19845161362-74; A@:?81197230("Lingle, C. Eisen, J. S. Marder, E.LFBlock of glutamatergic excitatory synaptic channels by chlorisondamineAnimal Chlorisondamine/*physiology Crabs/*physiology Glutamates/*physiology In Vitro Lobsters/*physiology Membrane Potentials/drug effects Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Synapses/drug effects/*physiology Mol Pharmacolt 1981192  349-5381185575Lingle, C. Marder, E.tHAA glutamate-activated chloride conductance on a crustacean muscleHAAnimal Chlorides/*metabolism Dose-Response Relationship, Drug Glutamates/*pharmacology GABA/pharmacology Ibotenic Acid/pharmacology Lobsters Membrane Potentials/drug effects Neural Inhibition/drug effects Neuromuscular Junction/*drug effects Picrotoxin/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.tF?A glutamate-activated inhibitory response on a 'crustacean neuromuscular preparation that receives cholinergic excitatory innervation is described. Glutamate produced a dose-dependent conductance increase to C1-ions. The response was mimicked by ibotenic acid, but not by quisqualic acid, and was blocked by picrotoxin.g Brain Res  1981 212 2  481-8 ,%Lingle, C. Marder, E. Nathanson, J.A. 19826/The role of cyclic nucleotides in invertebrates "Kebabian, J. Nathanson, J.A.RLCyclic Necleotides II: Physiology and Pharmacology, Handbook of Pharmacology Berlin Springer-VerlagG787-845.83294118 Lingle, C.PJBlockade of cholinergic channels by chlorisondamine on a crustacean muscleVPAcetylcholine/antagonists & inhibitors Animal Chlorisondamine/*pharmacology Dose-Response Relationship, Drug Ion Channels/*drug effects Lobsters Membrane Potentials/drug effects Muscles/drug effects Receptors, Cholinergic/*drug effects Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Synaptic Membranes/drug effects Time Factors Details of the blocking action of chlorisondamine, a ganglionic nicotinic blocker, on the excitatory cholinergic currents of the spiny lobster gastric mill 1 (g.m.1) muscle are described. The steady-state block of cholinergic ionophoretic currents produced by chlorisondamine is strongly voltage-dependent. During a hyperpolarizing voltage step, a sequence of ionophoretic agonist pulses in the presence of chlorisondamine shows a large interpulse interaction manifested as a gradual diminution in response amplitude. The extent of diminution is dependent on the number of the pulse in a series and not on the duration of the interval between pulses. The slowly developing blockade is entirely dependent on agonist application. If agonist application is suspended for various time intervals following the development of a given blocked level in chlorisondamine, no recovery from the block is observed whether the rest interval is at the step potential or at more depolarized potentials. Recovery from a given blocked level can be observed if, during a depolarizing voltage step (to -60 mV) away from the potential at which the block was established (-140 mV), agonist is applied before return to the initial potential (-140 mV). Chlorisondamine produces a dose-dependent reduction in excitatory junctional current (e.j.c.) decay rate that is linear with chlorisondamine concentration and markedly dependent on voltage (approximately equal to 35 mV/e-fold change). Reduction in the amplitude of e.j.c.s occurred at concentrations of chlorisondamine that produced no detectable effect on e.j.c. decay. Alterations in e.j.c. amplitude showed time- and use-dependent aspects similar to those observed for ionophoretic currents. These results are discussed primarily in terms of a sequential model in which, following the binding of chlorisondamine to the opened ion channel, the channel can undergo a transition to a stable-blocked state that requires reactivation by agonist to become unblocked. This stable-blocked state is considered a closed-blocked channel.J Physiol (Lond) 1983 339395-417HGF EDCB>83215235Lingle, C. Auerbach, A.CComparison of excitatory currents activated by different transmitters on crustacean muscle. I. Acetylcholine-activated channelsXQAcetylcholine/pharmacology/*physiology Animal Comparative Study Crabs/*physiology Electric Conductivity Homeostasis Lobsters/*physiology Muscles/*physiology Neuromuscular Junction/physiology Neurotransmitters/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology Time Factors ^XThe properties of acetylcholine-activated excitatory currents on the gm1 muscle of three marine decapod crustaceans, the spiny lobsters Panulirus argus and interruptus, and the crab Cancer borealis, were examined using either noise analysis, analysis of synaptic current decays, or analysis of the voltage dependence of ionophoretically activated cholinergic conductance increases. The apparent mean channel open time (tau n) obtained from noise analysis at -80 mV and 12 degrees C was approximately 13 ms; tau n was prolonged e-fold for about every 100-mV hyperpolarization in membrane potential; tau n was prolonged e- fold for every 10 degrees C decrease in temperature. Gamma, the single- channel conductance, at 12 degrees C was approximately 18 pS and was not affected by voltage; gamma was increased approximately 2.5-fold for every 10 degrees C increase in temperature. Synaptic currents decayed with a single exponential time course, and at -80 mV and 12 degrees C, the time constant of decay of synaptic currents, tau ejc, was approximately 14-15 ms and was prolonged e-fold about every 140-mV hyperpolarization; tau ejc was prolonged about e-fold for every 10 degrees C decrease in temperature. The voltage dependence of the amplitude of steady-state cholinergic currents suggests that the total conductance increase produced by cholinergic agonists is increased with hyperpolarization. Compared with glutamate channels found on similar decapod muscles (see the following article), the acetylcholine channels stay open longer, conduct ions more slowly, and are more sensitive to changes in the membrane potential. J Gen Physiol 1983814 547-694-Liu, Z. Golowasch, J. Marder, E. Abbott, L.F. 1998`YA model neuron with activity-dependent conductances regulated by multiple calcium sensors J Neurosci18 2309-2320yXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=3973678$Lnenicka, G. A. Atwood, H. L.d]Age-dependent long-term adaptation of crayfish phasic motor axon synapses to altered activitys*Adaptation, Physiological *Aging Animal Axons/*physiology Crayfish/growth & development Electric Stimulation Hoof and Claw/innervation Motor Neurons/*physiology Nervous System/growth & development Neuronal Plasticity Synapses/*physiology Time Factors Crustacean tonic and phasic motoneurons have neuromuscular synaptic properties corresponding with their functional requirements. Phasic axon synapses produce large excitatory postsynaptic potentials (EPSPs) which depress rapidly during repetitive activation. Tonic axon synapses generally produce smaller EPSPs which are more resistant to fatigue. To test whether nerve impulse activity of the motoneuron plays a role in the establishment of these synaptic properties, a phasic axon was tonically stimulated in vivo. The "fast" closer excitor of the crayfish claw, which normally fires few impulses, was stimulated for 2 hr/day at 5 Hz, through implanted electrodes. In young crayfish, this stimulation produced an 11-fold decrease in synaptic fatigue at the fast axon's neuromuscular synapses, as determined from measurements of EPSPs during 5 Hz stimulation of the fast axon for 30 min. In comparison with EPSPs of the contralateral control claw, the initial EPSP amplitude was 44% smaller and the final EPSP amplitude was 4.3 times larger for the chronically stimulated fast axon. These changes in EPSP amplitude are due to changes in transmitter release. This long-term adaptation of the fast axon to imposed tonic activity persists for at least 10 days after the effect has been established. The same chronic stimulation regimen produces significant, although less dramatic, results in adult crayfish. Compared to the contralateral control, the chronically stimulated fast axon showed no change in initial EPSP amplitude and only a 2-fold increase in the EPSP amplitude after 30 min of stimulation at 5 Hz. Thus, the decrease in synaptic fatigue was only 2- to 3-fold, much less than in young crayfish.(ABSTRACT TRUNCATED AT 250 WORDS)3973678 J Neurosci 198552459-67.XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=3746407.'Lnenicka, G. A. Atwood, H. L. Marin, L.nnhMorphological transformation of synaptic terminals of a phasic motoneuron by long-term tonic stimulationAnimal Crayfish Electric Stimulation Microscopy, Electron Mitochondria/ultrastructure Motor Neurons/*ultrastructure Support, Non-U.S. Gov't Synapses/*ultrastructureIn vivo stimulation of a relatively "silent" phasic crayfish motoneuron changes the ultrastructure of its synaptic terminals to a more tonic phenotype. The closer muscle of the crayfish claw is supplied by only 2 excitatory motoneurons, one of which is phasic and the other tonic. The ultrastructures of conditioned phasic, unconditioned phasic, and tonic motor terminals were compared. The terminals of the tonic motor axon were larger in cross-sectional area, had larger mitochondria, greater synaptic contact area, and were more varicose than unconditioned phasic terminals. Following long-term tonic stimulation of the phasic axon, its terminals became more varicose, mitochondrial cross-sectional area more than doubled, and synapses and mitochondria came into closer proximity, although mean terminal cross-sectional area did not change. Thus, the conditioned phasic terminals became more similar to those of the tonic motor axon. These changes in ultrastructure correlate with, and may be causally linked to, previously reported changes in neuromuscular synaptic physiology produced by in vivo tonic stimulation of this motoneuron. We conclude that the ongoing level of impulse activity can affect the ultrastructural differentiation of synaptic terminals and synapses of the phasic motoneuron. 3746407e J Neurosci 19866e8l2252-8.p4-LoFaro, T. Kopell, N. Marder, E. Hooper, S.L.s 1994LFSubharmonic coordination in networks of neurons with slow conductances Neural Comp6 69-844-LoFaro, T. Kopell, N. Marder, E. Hooper, S.L. 1994PIThe effect of ih currents on bursting pattern of pairs of coupled neurons\  Eeckman, F.H.0)Computation in Neurons and Neural Systems Boston Kluwer Academic Publishers 15-208 Lovett, D.L. Felder, D.L. 1989POntogeny of gut mophology in white shrimpPenaeus setiferus (Decapoda: Penaeidae)):J Morph 201253-272 Lovett, D.L. Felder, D.L. 1990]Ontogeny of kinematics in the gut of the white shrimp Penaeus setiferus (Decapoda: Penaeidae)6G J Crust Biol10 53-68ez Russell, D.F.o 1977iCentral control of pattern generators in the stomatogastric ganglion of the lobster Panulirus interruptus0T  San Diegon University of California Ph.D.78159683$Russell, D. F. Hartline, D. K.0)Bursting neural networks: a reexaminationoAction Potentials Animal Cell Membrane/physiology In Vitro Lobsters Membrane Potentials Motor Neurons/physiology Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Periodicity Support, U.S. Gov't, P.H.S.Many of the motor neurons in the lobster (Panulirus interruptus) stomatogastric ganglion exhibit plateau potentials; that is, prolonged regenerative depolarizations resulting from active membrane properties, that drive the neurons to fire impulses during bursts. Plateaus are latent in isolated ganglia but are unmasked by central input. These findings emphasize the role of cellular properties as compared to synaptic wiring in the production of cyclic motor patterns by ensembles of neurons.Science 1978 200 4340 453-6 Russell, D.F. 1979NHCNS control of pattern generation in the lobster stomatogastric ganglion Brain Res 177598-60282024946$Russell, D. F. Hartline, D. K.VOA multiaction synapse evoking both EPSPs and enhancement of endogenous burstingAnimal Axons/physiology Calcium/pharmacology Electric Stimulation Esophagus/innervation Evoked Potentials Ganglia/*physiology Gastrointestinal System/innervation Lobsters Neurons/physiology Support, U.S. Gov't, P.H.S. Synapses/drug effects/*physiologyeXRSelective stimulation of two identified input neurons called the 'IV neurons' has a dual influence on the endogenous bursting activity of certain 'PD' motorneurons in the stomatogastric ganglion of the spiny lobster. The effects include: (i) large, conventional and apparently monosynaptic EPSPs; and (ii) enhancement of the endogenous bursting of the pyloric dilator (PD) cells, seen as an increased amplitude of PD oscillations and a higher spiking rate during bursts. The burst enhancement decayed relatively slowly after stimulation ceased, over seconds or tens-of-seconds, depending on stimulus parameters. Modification of the voltage-dependent membrane properties of the PD cells appeared to underlie this effect. The dual-action nature of the IV-to-PD connection was confirmed by selectively blocking the brief EPSP component with 5 x 10(-4) M curare, under which conditions the burst enhancement still persisted. Data from low-Ca2+ experiments were consistent with a conventional mode of synaptic transmitter release underlying the burst enhancement. Enhancement was found to differ significantly from actions of injected current. The IV inputs appear to act on at least two types of synaptic receptors on PD neurons: a curare- sensitive receptor for the brief conventional EPSP, and a curare- resistant receptor for burst enhancement. Analogies may be drawn to the nicotinic and muscarinic cholinergic receptors of vertebrates. These findings may be considered within the contexts of multiaction synapses, modification of cellular properties, and mechanisms for the CNS activation of motor pattern generators. Brain Res 1981 2231 19-38csq>bdt98039404.(Marder, E. Christie, A. E. Kilman, V. L.\UFunctional organization of cotransmission systems: lessons from small nervous systemsAnimal Invertebrates/*physiology *Nervous System Physiology Neurotransmitters/physiology Support, U.S. Gov't, P.H.S. Synaptic Transmission/*physiology Tissue DistributionSmall invertebrate nervous systems allow one to ask a series of questions concerning the functional roles of cotransmitters. This review outlines some of the implications of cotransmission for target selectivity in complex neuropils. We suggest the possibility that a unique constellation of cotransmitters in individual identified modulatory neurons allows a specificity of action even when peptides may act over an extended distance, and when individual modulatory substances may be released from several modulatory neurons. 1995Invert Neurosci12 105-12 Using Smart Source Parsing96284088 Marder, E.2,Neural modulation: following your own rhythmAnimal Crabs Digestive System/innervation Ganglia, Invertebrate/physiology Neural Inhibition Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synaptic Transmission/physiology Recent studies of an invertebrate neural circuit show how presynaptic inhibition can play a key role in the generation of oscillatory activity, and can allow the directly affected axon terminal to engage in rhythmic activity independently of the rest of the neuron.V Curr Biol4 19966E29 119-21jchttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.pnas.org/cgi/content/full/93/24/1348197098420F@Marder, E. Abbott, L. F. Turrigiano, G. G. Liu, Z. Golowasch, J.>7Memory from the dynamics of intrinsic membrane currentseAnimal Cell Membrane/*physiology Learning/physiology Memory/*physiology Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/*physiology Time Factors.(Almost all theoretical and experimental studies of the mechanisms underlying learning and memory focus on synaptic efficacy and make the implicit assumption that changes in synaptic efficacy are both necessary and sufficient to account for learning and memory. However, network dynamics depends on the complex interaction between intrinsic membrane properties and synaptic strengths and time courses. Furthermore, neuronal activity itself modifies not only synaptic efficacy but also the intrinsic membrane properties of neurons. This paper presents examples demonstrating that neurons with complex temporal dynamics can provide short-term "memory" mechanisms that rely solely on intrinsic neuronal properties. Additionally, we discuss the potential role that activity may play in long-term modification of intrinsic neuronal properties. While not replacing synaptic plasticity as a powerful learning mechanism, these examples suggest that memory in networks results from an ongoing interplay between changes in synaptic efficacy and intrinsic membrane properties.Proc Natl Acad Sci U S A 1996932413481-6i96315616"Marder, E. Calabrese, R. L.6/Principles of rhythmic motor pattern generationrAnimal Circadian Rhythm/*physiology Motor Activity/*physiology Neural Networks (Computer) Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synaptic Transmission/*physiologyl0*Rhythmic movements are produced by central pattern-generating networks whose output is shaped by sensory and neuromodulatory inputs to allow the animal to adapt its movements to changing needs. This review discusses cellular, circuit, and computational analyses of the mechanisms underlying the generation of rhythmic movements in both invertebrate and vertebrate nervous systems. Attention is paid to exploring the mechanisms by which synaptic and cellular processes interact to play specific roles in shaping motor patterns and, consequently, movement. Physiol Rev 1996763687-717 Marder, E. 199782Computational dynamics in rhythmic neural circuitsThe Neuroscientist3295-302,.vnghttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/16/12/3950/96242091"Massabuau, J. C. Meyrand, P.jcModulation of a neural network by physiological levels of oxygen in lobster stomatogastric ganglioniNHAnimal Electrophysiology Ganglia, Invertebrate/drug effects/physiology Lobsters/*physiology Microcirculation/physiology Nervous System/cytology/drug effects/physiology Nervous System Physiology Neurons/drug effects/physiology Oxygen/*pharmacology/physiology Periodicity Pylorus/innervation/physiology Sensitivity and Specificity:3Although a large body of literature has been devoted to the role of O2 in the CNS, how neural networks function during long-term exposures to low but physiological O2 partial pressure (PO2) has never been studied. We addressed this issue in crustaceans, where arterial blood PO2 is set in the 1-3 kPa range, a level that is similar to the most frequently measured tissue PO2 in the vertebrate CNS. We demonstrate that over its physiological range, O2 can reversibly modify the activity of the pyloric network in the lobster Homarus gammarus. This network is composed of 12 identified neurons that spontaneously generate a triphasic rhythmic motor output in vitro as well as in vivo. When PO2 decreased from 20 to 1 kPa, the pyloric cycle period increased by 30- 40%, and the neuronal pattern was modified. These effects were all dose- and state-dependent. Specifically, we found that the single lateral pyloric (LP) neuron was responsible for the O2-mediated changes. At low PO2, the LP burst duration increased without change in its intraburst firing frequency. Because LP inhibits the pyloric pacemaker neurons, the increased LP burst duration delayed the onset of each rhythmic pacemaker burst, thereby reducing significantly the cycling frequency. When we deleted LP, the network was no longer O2-sensitive. In conclusion, we propose that (1) O2 has specific neuromodulator-like actions in the CNS and that (2) the physiological role of this reduction of activity and energy expenditure could be a key adaptation for tolerating low but physiological PO2 in sensitive neural networks. J Neurosci 19961612 3950-9Maynard, D.M. Sallee, A. 1970}Disturbance of feeding behavior in the spiny lobster, Panulirus argus, following bilateral ablation of the Medulla terminalis6ES Vergl Physiold66123-1401 Maynard, E.A. 1971QElectron microscopy of stomatogastric ganglion in the lobster, Homarus americanus?Tissue and Cell3137-149u Maynard, E.A. 1971yMicroscopic localization of cholinesterases in the nervous system of the lobsters, Panulirus argus and Homarus americanusSbgTissue and Cell3 215-250o73050298Maynard, D. M.Simpler networksAction Potentials Animal Ganglia/anatomy & histology/cytology/physiology Interneurons/physiology Lobsters/*physiology Microelectrodes Microscopy, Electron Models, Neurological Neurons/*physiology Pylorus/innervation Stomach/innervation Synapses/physiology Ann N Y Acad Sci 1972 193  59-72 74280324"Maynard, D. M. Dando, M. R.oThe structure of the stomatogastric neuromuscular system in Callinectes sapidus, Homarus americanus and Panulirus argus (Decapoda Crustacea)Animal Crabs/*anatomy & histology Lobsters/*anatomy & histology Motor Neurons/physiology Muscles/*innervation Nervous System/*anatomy & histology1("Philos Trans R Soc Lond B Biol Sci 1974 268  892L161-220 $Maynard, D.M. Selverston, A.I. 1975`YOrganization of the stomatogastric ganglion of the spiny lobster. IV. The pyloric systemJ Comp Physiol 100161-182 Maynard, D.M. Walton, K.D. 1975pjEffects of maintained depolarization of presynaptic neurons on inhibitory transmission in lobster neuropilJ Comp Physiol97215-243yMeier, T. Reichert, H. 1990jcNeuronal development in the crustacean nervous system studied by neuron-specific antibody labelling @:Wiese, K. Krenz, W.-D. Tautz, J. Reichert, H. Mulloney, B.*$Frontiers in Crustacean Neurobiology Baselo Birkhauser Verlag/523-579y Meiss, D.E. 1975voThe stomatogastric neuromuscular system of decapod crustacea. A comparative anatomical and physiological study University of Connecticut Ph.D.Meiss, D.E. Norman, R.S. 1977`YComparative study of the stomatogastric system of several decapod crustacea. I. SkeletonJ Morph 152 21-53Meiss, D.E. Norman, R.S. 1977d]Comparative study of the stomatogastric system of several decapod crustacea. II. MusculatureJ Morph 152 55-76XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=1320945 Meunier, C.UVPThe electrical coupling of two simple oscillators: load and acceleration effectsAnimal Biological Clocks/*physiology Invertebrates Mathematics Models, Neurological Nerve Net/*physiology Synapses/physiology Synaptic Transmission/physiologyWe consider two electrically coupled oscillators described by modified Fitzhugh-Nagumo equations. We study the relative influence of the individual cellular characteristics and the electrical coupling on the behavior of the coupled system. We show that, for similar oscillators, the load effect of the slow oscillator increases with the coupling strength. We prove that an asymmetry between the uncoupled bursters can accelerate the system with respect to the free cells, this effect depending on the characteristics of the coupling.'D>Department of Physics, Brandeis University, Waltham, MA 02254.1320945 1992 Biol Cybern672 155-64 Using Smart Source ParsingMeyrand, P. Moulins, M.n 1986VOMyogenic oscillatory activity in the pyloric rhythmic motor system of crustaceavJ Comp Physiol 158]489-503 Meyrand, P. 1987pjAppendix: Conditional regenerative properties in the pyloric dilator muscle: Their functional implications "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag 48-5692309023,%Meyrand, P. Weimann, J. M. Marder, E.eTNMultiple axonal spike initiation zones in a motor neuron: serotonin activationPJAnimal Axons/drug effects/*physiology Crabs Digestive System/innervation Electric Conductivity/drug effects Evoked Potentials/drug effects Ganglia/*physiology In Vitro Motor Neurons/drug effects/*physiology Muscle, Smooth/innervation Serotonin/*pharmacology Sucrose/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The late92309023,%Meyrand, P. Weimann, J. M. Marder, E.eTNMultiple axonal spike initiation zones in a motor neuron: serotonin activationPJAnimal Axons/drug effects/*physiology Crabs Digestive System/innervation Electric Conductivity/drug effects Evoked Potentials/drug effects Ganglia/*physiology In Vitro Motor Neurons/drug effects/*physiology Muscle, Smooth/innervation Serotonin/*pharmacology Sucrose/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The lateral gastric (LG) motor neuron of the stomatogastric nervous system of the crab Cancer borealis has a large soma in the stomatogastric ganglion (STG). The LG motor neuron makes inhibitory synaptic connections within the neuropil of the STG, and also projects to the periphery, where it innervates a series of muscles that control the movements of the lateral teeth of the gastric mill. The LG motor neuron has a spike initiation zone close to its neuropilar integrative regions, from which spikes propagate orthodromically to the muscles. Additionally, under certain conditions, the LG neuron can initiate spikes at peripheral axonal sites that can be 0.5-2.0 cm from the STG. Peripherally initiated spikes propagate antidromically into the STG and also propagate to the muscle. The peripheral spike initiation zones are often active in combined preparations in which the muscles are left attached. When the muscles are removed, depolarization of the LG soma together with 5-HT applied to the motor nerve also evokes peripheral spike initiation. At a given 5-HT concentration, the duration of the trains of antidromic spikes can be controlled by current injection into the soma, suggesting the presence of a slow voltage-dependent conductance in the LG axon. The antidromic spikes contribute to lengthening of the duration of contraction in some of the muscles innervated by the LG, but do not evoke IPSPs onto LG follower neurons. Thus, the LG neuron can send different signals to its peripheral and central targets. J Neurosci 19921272803-12$& Abarbanel1998 Abarbanel1999 Abarbanel2000 Abarbanel2000B Abarbanel2000 Abarbanel2001 Abarbanel2001 Abarbanel2001 Abarbanel2002k Abarbanel2003 Abbott1990 Abbott1991 Abbott1991 Abbott1992n Abbott1992 Abbott19922F Abbott1992 Abbott19935 Abbott19939m Abbott1993p Abbott1993 Abbott19939G Abbott1993H Abbott1993 Abbott1994o Abbott1994J Abbott1994 Abbott19941l Abbott1995 Abbott1995q Abbott1996D Abbott1996a Abbott19961P Abbott1997 Abbott1998 Abbott19981* Abbott1998B Abbott19989. Abbott19991 Abbott19999 Abbott19999w Abbott1999o Abbott20010` Abbott2001 Abbott20022 Abel19999 Abele1985 Abele1986 Abele1989 Adams1996Agricola1999% Akoev2000 Albert1986i Allen1978 An2003,Anderson1976Anderson1980Anderson1981gAnderson1981]Anderson19866 Anderson1987t Ando19861A Archavsky1997 Arshavsky1993 Arshavsky1994 Atwood1975  Atwood1977  Atwood1978C Atwood19858D Atwood19868 Auerbach1981=Auerbach1983>Auerbach1983  Ayali1998 Ayali1998 Ayali1998 Ayali1999 Ayali2000 Ayali2002 Ayali2002 Ayali2004 Ayers1977 Ayers1979 Ayers1984R Ayers1987 Bal1988 Bal1990 Bal1991 Bal1994 Baldwin1993 Baldwin1995K Baldwin1995M Baldwin1997 Baldwin2003 Barazangi1995 Barker1972 Barker1977 Barker1979 Barker19818 Barker19818/ Barker19833 Barker1987 Baro1994 Baro1996 Baro1996" Baro1996  Baro1997 Baro1997r% Baro1997 Baro2000! Baro2001 Baro20010 Baro20040$ Bartos1997| Bartos1998# Bartos1999% Bedrov2000 Beenhakker2002& Beenhakker2004Q Beenhakker2004 Beenhakker2004 Beenhakker2004Belanger1989( Beltz1983' Beltz1984l Beltz1994j Beltz1995 Beltz2003) Bem2002* Benson1984+ Bidaut1980- Billimoria20037 Billimoria2003 Billimoria2003  Birmingham19989. Birmingham1999E Birmingham2000, Birmingham2001 Birmingham2001- Birmingham2003l Bittner1995 Blanck199770 Blitz19951 Blitz1997/ Blitz19992 Blitz1999 Blitz2001& Blitz2004 Blitz2004 Bohm199393 Bohm19955 Bohm19976 Bohm19974 Bohm2001 Booth1990 Booth2003 Booth2003X Borner2003 Bose20011 Bose20033 Bose20033 Bose2004r Bucher20017 Bucher2003 Bucher2004 Bucher20058 Buchholtz1992 Buchholtz1992m Buchholtz1993 Buchman2002 Buchner1999 Budelli1981 Buisson1990 Buisson19919 Cabirol-Pol2000 Cain20042: Caine1975; Calabrese1991 Calabrese1993 Calabrese1993s Calabrese1996< Calabrese1998= Calabrese1999Caldwell1978>Callaway1987? Calvin1977 Calvin19797B Cardi1990@ Cardi1991A Cardi1994 Cardi1994 Cardi1994C Carlton1989D Casasnovas1995j Casasnovas1995 Casasnovas1998 Casasnovas1998 Casey1999 Castelfranco2003UCattaert1999ECazalets1987FCazalets1987GCazalets1990HCazalets1990BCazaletz1990I Chabaud1991! Chang1998p Chanussot1974N Cherny20033 Cherny20044o Chiba1991J Chiba1992p Chiba1993q Chiba1994OChristie19940Christie1995KChristie1995LChristie1995tChristie1995MChristie1997PChristie1997/Christie1999Christie2000hChristie20000NChristie20037Christie20030Christie2003QChristie2004Christie2004S Claiborne1984T Claiborne1984R Claiborne1987c Claiborne1992U Clarac1999 Clark2004N Clason20033 Clason20044 Cleland1993W Cleland1995V Cleland1996X Cleland1997Y Cleland1998Z Clemens1998[ Clemens1998^ Clemens1998\ Clemens1999] Clemens2001_ Cohen1990 Cohen2002 Cole1994 Cole1996 Cole19961" Cole1996c Coleman1992` Coleman1994b Coleman1994 Coleman1994a Coleman1995 Coleman1996/ Coleman1999h Coleman2000h Combes1993f Combes1995g Combes1997Z Combes19988d Combes1999e Combes1999Coniglio1995kConiglio1995kConiglio1996Coniglio1997k* Cooke1984r Cooke1986s Cooke1990i Coombs1978 Corey1979Cottrell1992 Cournil1982k Cournil1984E Cournil1987 Cournil1989m Cournil1990n Cournil1990c Cournil1992l Cournil1994 Cournil1994j Cournil1995 Cowan2004o Dall1983q Dando1969s Dando1972p Dando1974 ljo\a`p(m _ .n81Marder, E. Abbott, L.F. Kepler, T.B. Hooper, S.L. 1992ZTModification of oscillator function by electrical coupling to nonoscillatory neurons Baar, E. Bullock, T.H."Induced Rhythms in the Brain Boston  Birkhauser287-296s"Marder, E. Selverston, A.I. 19920*Modeling the stomatogastric nervous system BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MAP  MIT Press161-196eMarder, E. Weimann, J.M. 1992ZSModulatory control of multiple task processing in the stomatogastric nervous system & Kien, J. McCrohan, C. Winlow, B.0)Neurobiology of Motor Programme Selection New York Pergamon Press 3-1982Marder, E. Weimann, J.M. Kepler, T.B. Abbott, L.F. 1992tmComputational implications of a serotonin-sensitive region of axonal membrane on a dual function motor neuron Eeckmann, F.H.,%Neural Systems: Analysis and ModelingP Boston Kluwer Academic Pressm377-390H Marder, E. 1993PIModulating membrane properties of neurons: Role in information processing Poggio, T.A. Glaser, D.A.81Exploring Brain Functions: Models in Neurosciencee West Sussex, UKt John Wiley & Sons Ltd. 27-42Dahlem Workshop Reportsb[Marder, E. Abbott, L.F. Buchholtz, F. Epstein, I.R. Golowasch, J. Hooper, S.L. Kepler, T.B.o 1993zsPhysiological insights from cellular and network models of the stomatogastric nervous systems of lobsters and crabsiAm Zoole33 29-394.Marder, E. Abbott, L.F. Sharp, A.A. Kopell, N. 1993<6Electrical coupling in networks containing oscillators :3Rudomin, P. Arbib, M.A. Cervates-Peres, F. Romo, R.D=Neuroscience: From Neural Networks to Artificial Intelligencee Berlin Springer-Verlagr 33-427 Marder, E. 1994"Polymorphic neural networksn Curr Bioli428l 752-4 95041371Animal Aplysia/physiology Behavior, Animal/*physiology Invertebrates/*physiology Models, Neurological Nerve Net/*physiology Serotonin/physiology Synapses/physiologyRecent work on small invertebrate nervous systems provides new insights into the way in which neurons are organized into functional networks to generate behavior. Invertebrate neurobiology Marder, E. 19940*Dynamic modulation of neurons and networks ,%Cowan, J.D. Tesauro, G. Alspector, J.81Advances in Neural Information Processing Systems  San Franciscoe Morgan Kaufman Publishersn6&511-518XQMarder, E. Abbott, L.F. LeMasson, G. O'Neil, M.B. Renaud-LeMasson, S. Sharp, A.A. 1994leBiological simulators: Computer modification of neuronal conductances and formation of novel networksn "Stenger, D.A. McKenna, T.M.82Enabling Technologies for Cultured Neural Networks  San Diegov Academic Press261-275P\Vhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://biomednet.com/article/nb561296403291Marder, E. Abbott, L. F.Theory in motionAnimal Human *Models, Neurological Movement/*physiology Nerve Net/cytology/physiology Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Modeling studies are now a significant part of mainstream research in motor control. Novel and classical modeling techniques used in recent work on small and large motor systems illustrate the different roles that models play in furthering our understanding of motor systems. The models presented reveal single neuron short-term memory, unexpected effects of reciprocal inhibition and methods for decoding activity in large populations of neurons.Curr Opin Neurobiol 199556 832-40VU 83149457HAMarder, E. O'Neil, M. Grossman, R. I. Davis, K. R. Taveras, J. M.+("Cholinergic actions of metrizamide}Acetylcholine/pharmacology Acetylcholinesterase/metabolism Action Potentials/drug effects Animal Cholinergic Fibers/drug effects/*physiology Crabs Dose-Response Relationship, Drug Electrophysiology In Vitro Metrizamide/*pharmacology Muscles/enzymology Neural Conduction/drug effects Neuromuscular Junction/drug effects/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.In a study of the possible mechanisms of the clinical side effects of metrizamide, it was applied to several in vitro model preparations. It was shown that, although high metrizamide concentrations are without noticeable effect on many basic neuronal functions, metrizamide does interfere with cholinergic mechanisms. At concentrations equivalent to, or significantly lower than, those probably achieved during clinical procedures, metrizamide is both an inhibitor of the enzyme acetylcholinesterase and an antagonist of cholinergic transmission. These data suggest the possibility that some of the side effects resulting from clinical procedures employing metrizamide may be explained by its actions on cholinergic synapses.AJNR Am J Neuroradiol 198341 61-585081885 Marder, E.b\Roles for electrical coupling in neural circuits as revealed by selective neuronal deletionsAnimal Cell Survival Electrophysiology Isoquinolines/diagnostic use Light Neural Pathways/*physiology Neurons/drug effects/physiology/radiation effects Peptide Hydrolases/pharmacology Support, U.S. Gov't, P.H.S. Synapses/physiology Time FactorsUnderstanding fully the operation of a neural circuit requires both a description of the individual neurones within the circuit as well as the characterization of their synaptic interactions. These aims are often particularly difficult to achieve in neural circuits containing electrically-coupled neurones. In recent years two new methods (photoinactivation after Lucifer Yellow injection and intracellular injection of pronase) have been employed to delete selectively single neurones or small groups of neurones from neural circuits. These techniques have been successfully used in the analysis of circuits containing electrically-coupled neurones. In several systems new roles for electrical synapses in the integrative function of neural circuits have been proposed. In the nervous systems of both the leech and lobster it is now thought that synaptic interactions previously thought to be direct are mediated through an interposed, electrically-coupled neurone. In the pyloric system of the stomatogastric ganglion of the lobster, Panulirus interruptus, the Lucifer Yellow photoinactivation technique has permitted a separate analysis of the properties of several electrically-coupled neurones previously thought quite similar. We now know that the Anterior Burster (AB) interneurone and the Pyloric Dilator (PD) motor neurones, which together act as the pacemaker ensemble for the pyloric network, differ in many regards including their intrinsic ability to generate bursting pacemaker potentials, their neurotransmitters, their sensitivity to some neurotransmitters and hormones, the neural inputs they receive and their pattern of synaptic connectivity. These results will be discussed in the context of the role of electrical coupling in neuronal integration. J Exp Biol 1984 112 147-67 Marder, E. 1984LEMechanisms underlying neurotransmitter modulation of neuronal circuit TINS7 48-53#Meyrand, P. Simmers, J. Moulins, M.n|vDynamic construction of a neural network from multiple pattern generators in the lobster stomatogastric nervous systemd^Animal Axonal Transport Axons/physiology Digestive System/innervation Electric Stimulation In Vitro Lobsters Models, Neurological Motor Neurons/physiology Muscle, Smooth/innervation Nerve Net/*physiology Nervous SyMeyrand, P. Moulins, M. 1988Phylogenetic plasticity of crustacean stomatogastric circuits. I. Pyloric pattern and pyloric circuit of the shrimp Palaemon serratusu J Exp Biol 138107-13291186208Meyrand, P. Marder, E.PJMatching neural and muscle oscillators: control by FMRFamide-like peptides|vAnimal Dose-Response Relationship, Drug Fluorescent Dyes/diagnostic use Immunohistochemistry Isoquinolines/diagnostic use Muscles/drug effects Nervous System/*physiology *Nervous System Physiology Neuropeptides/pharmacology/*physiology Oscillometry Peptides/pharmacology/*physiology Shrimp/*physiology Stomach/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.Stomatogastric nervous systems of the shrimp, Palaemon serratus, were stained with antisera raised against the peptide FMRFamide. FMRFamide- like immunoreactivity was found in fibers in the input nerve to the stomatogastric ganglion (STG), in several STG somata, in dense neuropil in the STG, in the motor nerves that innervate the dilator muscles of the pyloric region, but not in the pyloric dilator (PD) motor neurons. FMRFamide and several FMRFamide-like peptides elicited sequences of rhythmic depolarizations and contractions of the pyloric dilator muscle. As peptide concentrations were increased, a discrete threshold for contraction was found, above which contractions were initiated with a decreasing latency in an all-or-none fashion. Muscles stopped rhythmically contracting after many seconds to several minutes of activity; the duration of spontaneous oscillatory activity in peptide was proportional to the concentration of applied peptide. In the absence of peptide, each motor neuron discharge evoked small graded muscle contractions. During peptide-induced oscillations, motor neuron activity did not always entrain muscle oscillations. After spontaneous oscillations had stopped, when the motor neurons were stimulated in the presence of the peptide, each motor neuron burst evoked large amplitude contractions as a result of the peptide-induced regenerative properties of the muscle membrane. J Neurosci 1991114o1150-61y91226535*#Meyrand, P. Simmers, J. Moulins, M.od^Construction of a pattern-generating circuit with neurons of different networks [see comments]Animal Digestive System/*innervation Ganglia/*physiology Lobsters Membrane Potentials Models, Neurological Motor Neurons/physiology Muscle, Smooth/*innervation Neurons/*physiology Periodicity Synapses/physiology  Nature 1991 351- 6321 60-3 ^X]v\~}[ZYXWylxv 84241936Marder, E. Eisen, J. S.lfTransmitter identification of pyloric neurons: electrically coupled neurons use different transmittersF@Acetylcholine/pharmacology Animal Electrophysiology Glutamates/pharmacology Interneurons/drug effects/physiology Lobsters Motor Neurons/drug effects/*physiology Neural Inhibition Neurotransmitters/*physiology Parasympatholytics/pharmacology Pyloric Antrum/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. {The neurotransmitters mediating the synaptic interactions among the neurons of the pyloric system of the stomatogastric ganglion (STG) of the lobster, Panulirus interruptus, were examined using a combination of electrophysiological, pharmacological, and biochemical techniques. Iontophoretically applied L-glutamate inhibited all motor neurons of the pyloric system. This inhibitory response was blocked by low concentrations of picrotoxin but unaffected by atropine. The anterior burster (AB) interneuron, pyloric dilator (PD) motor neurons, and ventricular dilator (VD) motor neuron were depolarized and excited by iontophoretically applied acetylcholine (ACh). The lateral pyloric (LP) and pyloric (PY) constrictor motor neurons were inhibited by ACh and by the cholinergic agonist, carbachol. These inhibitory cholinergic responses were blocked by atropine but not by picrotoxin. The inhibitory postsynaptic potentials (IPSPs) evoked by the constrictor motor neurons were blocked by picrotoxin but not by atropine. Taken together with previously published data (15, 18), this suggests that the constrictor motor neurons release glutamate at both their excitatory neuromuscular junctions and their inhibitory intraganglionic junctions. The lucifer yellow photoinactivation technique (27) was used to study separately the neurotransmitters released by the electrically coupled PD and AB neurons. The AB-evoked IPSPs were blocked by picrotoxin but not by atropine. The PD-evoked IPSPs were blocked by atropine and other muscarinic antagonists but not by picrotoxin. Somata of PD neurons contained choline acetyltransferase (CAT) activity, but somata of AB neurons contained no detectable CAT activity. On the basis of the data in this paper and previously published data (17, 18), we conclude that the PD neurons release ACh at both their excitatory neuromuscular junctions and their inhibitory intraganglionic connections. Although the AB neuron is electrically coupled to the PD neurons, the AB neuron is not cholinergic. Glutamate is a likely transmitter candidate for the AB neuron. These data show that electrically coupled neurons can release different transmitters. Furthermore, these data show that an IPSP can be the result of the combined actions of two different neurotransmitters, each released from a different neuron. The functional consequences of these conclusions are explored in the following papers (9, 22).J Neurophysiol 19845161345-61Marder, E. Hooper, S. L. 1985XQNeurotransmitter modulation of the stomatogastric ganglion of decopod crustaceansn Selverston, A.("Model neural networks and behavior Plenum319-337XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=2869069.'Marder, E. Hooper, S. L. Siwicki, K. K.vpModulatory action and distribution of the neuropeptide proctolin in the crustacean stomatogastric nervous system Animal Chromatography, High Pressure Liquid Comparative Study Crabs/*physiology Fluorescent Antibody Technique Ganglia/*physiology Lobsters/*physiology Neurotransmitters Oligopeptides/*physiology Radioimmunoassay Species Specificity Support, U.S. Gov't, P.H.S. Synaptic TransmissionImmunocytochemical methods were used to map the distribution of proctolinlike immunoreactivity in the stomatogastric nervous systems (stomatogastric ganglion (STG), paired commissural ganglia (CG), oesophageal ganglion (OG), and connecting nerves) of three crustacean species: Panulirus interruptus, Cancer borealis, and Homarus americanus. Although the patterns of proctolinlike staining were similar among the three species, some differences were also observed. Over 70% of the proctolinlike material in STGs, as measured by radioimmunoassay, was indistinguishable from authentic proctolin in reverse-phase high-performance liquid chromatography. Bath application of proctolin to STGs from Cancer and Panulirus induced characteristic and robust (though somewhat different) changes in their motor patterns. The threshold concentration was approximately 10(-9)M proctolin, and the effects were dose-dependent. These data suggest that the neuropeptide proctolin serves as a neuromodulator of the stomatogastric ganglion.b2869069o J Comp Neurold 1986 243 4i454-67.n Marder, E. 1987,%Neurotransmitters and neuromodulators "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag263-300 Marder, E. 1987"The stomatogastric ganglion  Adelman, G.& The Encyclopedia of Neuroscience Boston  Birkhauser 1143-114488334690 Marder, E.*$Modulating a neuronal network [news]81Animal Lobsters *Neural Pathways Stomach/injuriesl Nature 1988 335 6188 296-7 Marder, E. 1989F?Introduction: Modulation of neural networks underlying behavior Altman, J. Marder, E. SINS1 3-4 Marder, E. 1989$Modulation of neural networks 2,Erber, J. Menzel, R. Pfluger, H.-J. Todt, D.$Neural Mechanisms of Behavior  Stuttgart Georg Thieme Verlag 55-60mMarder, E. Meyrand, .M. 198981Chemical modulation of oscillatory neural circuit  Jacklet, J.w(!Neuronal and Cellular Oscillators New York Marcel Dekker, Inc.317-338/Marder, E. Nusbaum, M.P. 1989\UPeptidergic modulation of the motor pattern generators in the stomatogastric ganglion Carew, T.C. Kelley, D.2+Perspectives in Neural Systems and Behaviorr New York Alan R. Liss, Inc. 73-91r91226527 Marder, E.*$A new act to swallow [news; comment]\VAnimal Crustacea Digestive System/*innervation Ganglia/*physiology Neurons/*physiology Nature 1991 3512 632118 Marder, E. 1991*#Modifiability of pattern generationCurr Opin Neuronbiol1571-576 Marder, E. 1991Plateaus in time Curr Biol1326-327.h92005630Mortin, L. I. Marder, E.Differential distribution of beta-pigment-dispersing hormone (beta-PDH)- like immunoreactivity in the stomatogastric nervous system of five species of decapod crustaceans2+Animal Crabs/*metabolism Crayfish/*metabolism Fluorescent Antibody Technique Immune Sera/immunology Immunohistochemistry Lobsters/*metabolism Nervous System/*immunology/metabolism/ultrastructure Neurons/immunology/metabolism/ultrastructure Peptides/*immunology/metabolism Support, U.S. Gov't, P.H.S. Pigment-dispersing hormone (PDH) acts to disperse pigments within the chromatophores of crustaceans. Using an antibody raised against beta- PDH from the fiddler crab Uca pugilator, we characterized the distribution of beta-PDH-like immunoreactivity in the stomatogastric nervous system of five decapod crustaceans: the crabs, Cancer borealis and Cancer antennarius, the lobsters, Panulirus interruptus and Homarus americanus, and the crayfish, Procambarus clarkii. No somata were stained in the stomatogastric ganglion (STG) or the esophageal ganglion in any of these species. Intense PDH-like staining was seen in the neuropil of the STG in P. interruptus only. In all 5 species, cell bodies, processes, and neuropil within the paired circumesophageal ganglia (CGs) showed PDH-like staining; the pattern of this staining was unique for each species. In each CG, the beta-PDH antibody stained: 1 large cell in C. borealis; 3 small to large cells in C. antennarius; 3-8 medium cells in P. clarkii; 1-4 small cells in H. americanus; and 13-17 small cells in P. interruptus. The smallest cell in each CG in C. antennarius sends its axon, via the inferior esophageal nerves, into the opposite CG; this pair of cells, not labeled in the other species studied, may act as bilateral coordinators of sensory or motor function. These diverse staining patterns imply some degree of evolutionary diversity among these crustaceans. A beta-PDH-like peptide may act as a neuromodulator of the rhythms produced by the stomatogastric nervous system of decapod crustaceans.Cell Tissue Res 1991 2651 19-33(!Moulins, M. Vedel, J. Dando, M.R. 1974ngRelations fonctionnelles entre sequences motrices centralement programmees chez les crustaces decapodesC R Acad Sci Paris D 279A 1895-1898 78048125Moulins, M. Vedel, J. P.nh[Central organization of rhythmic motor activity of the foregut in decapoda Crustacea (author's transl)]:3Action Potentials Animal English Abstract Ganglia/*physiology Gastrointestinal Motility Gastrointestinal System/innervation In Vitro Lobsters/anatomy & histology/*physiology Motor Neurons/*physiology Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Periodicity Synapses/physiology  1977 J Physioly734*471-510m Using Smart Source Parsing 0)Nadim, F. Manor, Y. Kopell, N. Marder, E.`ZSynaptic depression creates a switch that controls the frequency of an oscillatory circuitPJAction Potentials/*physiology Animal Computer Simulation Digestive System/*innervation Feedback Ganglia, Invertebrate/physiology Lobsters *Models, Neurological Nerve Net/physiology Neuronal Plasticity/*physiology Neurons/*physiology Oscillometry Periodicity Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/*physiologySynaptic depression is a form of short-term plasticity exhibited by many synapses. Nonetheless, the functional significance of synaptic depression in oscillatory networks is not well understood. We show that, in a recurrent inhibitory network that includes an intrinsic oscillator, synaptic depression can give rise to two distinct modes of network operation. When the maximal conductance of the depressing synapse is small, the oscillation period is determined by the oscillator component. Increasing the maximal conductance beyond a threshold value activates a positive-feedback mechanism that greatly enhances the synaptic strength. In this mode, the oscillation period is determined by the strength and dynamics of the depressing synapse. Because of the regenerative nature of the feedback mechanism, the circuit can be switched from one mode of operation to another by a very small change in the maximal conductance of the depressing synapse. Our model was inspired by experimental work on the pyloric network of the lobster. The pyloric network produces a simple motor rhythm generated by a pacemaker neuron that receives feedback inhibition from a depressing synapse. In some preparations, elimination of the synapse had no effect on the period of the rhythm, whereas in other preparations, there was a significant decrease in the period. We propose that the pyloric network can operate in either of the two modes suggested by the model, depending on the maximal conductance of the depressing synapse.'Department of Mathematics, New Jersey Institute of Technology and Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA. farzan@andromeda.rutgers.edu10393973http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10393973 http://www.pnas.org/cgi/content/full/96/14/8206 http://www.pnas.org/cgi/content/abstract/96/14/8206 Proc Natl Acad Sci U S A 199996148206-11.TS76240178 Marder, E.LFCholinergic motor neurones in the stomatogastric system of the lobsterTNAcetylcholine/*physiology Animal Cholinesterase Inhibitors/pharmacology Digestive System/innervation Edrophonium/pharmacology Ganglia/physiology Glutamates/pharmacology/physiology In Vitro Lobsters/*physiology Membrane Potentials/drug effects Motor Neurons/*physiology Muscles/drug effects Receptors, Cholinergic Synaptic Transmission}1. A study of the neurotransmitters used by each of the eleven types of excitatory motor neurones (identified according to the muscle innervated) of the lobster stomatogastric ganglion was undertaken. 2. The dorsal dilator muscle is innervated by the two motor neurones designated 'PD'. Bath and iontophoretic applications of acetylcholine (ACh) produce contractures and depolarizations respectively in the dorsal dilator muscle. 3. Pharmacological experiments support the cholinergic nature of the excitatory junctional potentials (e.j.p.s) recorded in the dorsal dilator muscle when the PD motor nerve is stimulated. 4. The apparent reversal potentials for the e.j.p.s and the iontophoretic ACh response in the dorsal dilator muscle are the same. 5. On the basis of choline acetyltransferase assays on identified stomatogastric ganglion motor neurone somata and tension measurements on the muscles innervated by each type of stomatogastric ganglion motor neurone, a transmitter candidate was established for each type of motor neurone. Motor neurones named VD, LPG, GM, MG, LG, and DG are putatively cholinergic. L-Glutamate is a transmitter candidate for the motor neurones called LP, PY, IC, and AM. 6. Potential correlations between the distribution of putatively cholinergic and glutaminergic motor neurones and the electrical coupling among the stomatogastric ganglion motor neurones are discussed.rJ Physiol (Lond) 1976 257 1s 63-86L79007175& Marder, E. Paupardin-Tritsch, D.|The pharmacological properties of some crustacean neuronal acetylcholine, gamma-aminobutyric acid, and L-glutamate responses\UAcetylcholine/*pharmacology Animal Chlorides/physiology Crabs/*physiology Ganglia/cytology/drug effects Glutamates/*pharmacology GABA/*pharmacology In Vitro Male Membrane Potentials/drug effects Neurons/drug effects/*physiology Picrotoxin/pharmacology Potassium/physiology Receptors, Cholinergic/drug effects/physiology Synaptic Transmission \U1. A study was performed of the L-glutamate, gamma-aminobutyric acid (GABA), and acetylcholine (ACh) responses of cells in the stomatogastric ganglion of the crab, Cancer pagurus. 2. Ionophoretic or pressure application of L-glutamate revealed three classes of responses: a K+-dependent inhibition which reversed at 15-20 mV more negative than the resting potential; a Cl- dependent inhibitory response which was at equilibrium at the resting potential; and a depolarizing response. 3. Ionophoretic or pressure applications of GABA likewise produced three kinds of responses: an increase in K+ conductance, an increase in Cl- conductance, and a depolarizing response. 4. Picrotoxin (10(-6)-10(-5) M) was effective in blocking both the glutamate inhibitory responses. 10(-4) M-picrotoxin, which was necessary to produce a 50% block of the GABA-K+-dependent response, had no effect on the GABA-Cl- response. 5. beta-Guanidinopropionic acid (beta-GP) was found to be an agonist for the GABA-K+ response, but was ineffective in mimicking or blocking the GABA-Cl- response. 6. ACh applications produced large depolarizing responses with a pharmacological profile similar to that of the nicotinic ganglionic response in vertebrates. 7. The muscarinic agonist, acetyl-beta-methyl choline (MeCh), produced depolarizations which decreased in amplitude as the membrane was hyperpolarized from -40 to -100 mV. Pilocarpine and oxotremorine produced changes in the endogenous activity of ganglionic neurones. 8. Implications of these results for the identification of synaptic transmitters in the somatogastric ganglion are discussed.J Physiol (Lond) 1978 280 213-3680089379& Marder, E. Paupardin-Tritsch, D.6/Picrotoxin block of a depolarizing ACh responsee2+Acetylcholine/*antagonists & inhibitors Animal Crabs Dose-Response Relationship, Drug GABA/pharmacology Ion Channels/drug effects Membrane Potentials/drug effects Neuromuscular Junction/drug effects Picrotoxin/*pharmacology Sodium/metabolism Synapses/drug effects Synaptic Transmission/*drug effectsM Brain Resa 1980 181s1  223-7 81095509& Marder, E. Paupardin-Tritsch, D.VPThe pharmacological profile of the acetylcholine response of a crustacean muscleAcetylcholine/*pharmacology Animal Bungarotoxins/pharmacology Crabs/*physiology Muscle Contraction/drug effects Neuromuscular Junction/physiology Parasympathomimetics/pharmacology Receptors, Muscarinic/drug effects Stomach/innervation Support, Non-U.S. Gov't A pharmacological analysis was made of the depolarizing acetylcholine (ACh) response found on the gastric mill I muscles of the crabs Cancer pagurus, Cancer irroratus and Cancer borealis. Acetylcholine, carbamylcholine, trimethylammonium, nicotine, and dimethyl-4-phenyl- piperazinium were effective in producing contractures and depolarizations in these muscles. No response to decamethonium, suberyldicholine, acetyl-beta-methylcholine, carbamyl-beta- methylcholine, pilocarpine and oxotremorine could be detected. High concentrations of muscarinic agonists (10(-4) to 10(-3) M) potentiated and prolonged the ACh iontophoretic response. When the acetylcholinesterase activity was inhibited with neostigmine, or when the response was elicited with carbamylcholine, muscarinic agonists partially inhibited the response. ACh responses were most effectively blocked by vertebrate nicotinic ganglionic antagonists, including dihydro-beta-erythroidine, pempidine, and mecamylamine. alpha- Bungarotoxin was without effect on the ACh response. J Exp Biol 198088 147-59 Marder, E. 1982,&Review of neuropharmacology of incects Ciba Foundation Symposium Pitman Ltd. Science 217924-925 dk:jrih>g.\Uhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=0010996080l Marder, E.My word. Colored chalk'^WVolen Center, Brandeis University, 415 South Street, Massachusetts 02454, Waltham, USA.0 0010996080 Curr BiolB 20001017 R613.- Marder, E.Bitter and twisted'PJBiology Department, Volen Center, Brandeis University, Waltham, 02454, USA10662654 Curr Biol  2000101P R1. |http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10662654 http://www.biomednet.com/article/bb10a74ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11298422U Marder, E.Moving rhythmsAnimal Human Models, Neurological *Movement Muscle Contraction/physiology *Nervous System Physiology Neural Pathways Neuromuscular Junction/physiology Neurons/physiology Psychomotor Performance Reflex, Stretch Spinal Cord/physiology'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.11298422 Nature 2001 410 6830 755.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11728329Marder, E. Bucher, D.F@Central pattern generators and the control of rhythmic movementsAnimal Human Movement/*physiology Nerve Net/*physiology Neurons/physiology Neurotransmitters/physiology Spinal Cord Injuries/physiopathologyCentral pattern generators are neuronal circuits that when activated can produce rhythmic motor patterns such as walking, breathing, flying, and swimming in the absence of sensory or descending inputs that carry specific timing information. General principles of the organization of these circuits and their control by higher brain centers have come from the study of smaller circuits found in invertebrates. Recent work on vertebrates highlights the importance of neuro-modulatory control pathways in enabling spinal cord and brain stem circuits to generate meaningful motor patterns. Because rhythmic motor patterns are easily quantified and studied, central pattern generators will provide important testing grounds for understanding the effects of numerous genetic mutations on behavior. Moreover, further understanding of the modulation of spinal cord circuitry used in rhythmic behaviors should facilitate the development of new treatments to enhance recovery after spinal cord damage.'~xVolen Center, MS 013, Brandeis University, 415 South Street, Waltham, Massachusetts 02454-9110, USA. marder@brandeis.edu11728329 Curr Biol 20011123R986-96.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=12015611 Marder, E.HANon-mammalian models for studying neural development and functionBEarly neuroscientists scoured the animal kingdom for the ideal preparation with which to study specific problems of interest. Today, non-mammalian nervous systems continue to provide ideal platforms for the study of fundamental problems in neuroscience. Indeed, the peculiarities of body plan and nervous systems that have evolved to carry out precise tasks in unique ecological niches enable investigators not only to pose specific scientific questions, but also to uncover principles that are general to all nervous systems.12015611 Nature 2002 417  6886318-21.cZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11894076 Marder, E..'Developmental biology: senseless motiona\UAnimal Drosophila melanogaster/*embryology/genetics/growth & development/*physiology Embryo, Nonmammalian/*embryology/*innervation/metabolism/physiology Larva/growth & development/*physiology Motor Activity/*physiology Neurons, Afferent/physiology Peripheral Nervous System/embryology/metabolism/*physiology Tetanus Toxin/genetics/metabolismg11894076 Nature 2002 416p 6877 131-2.124479792412 2002 Dec\VModeling stability in neuron and network function: the role of activity in homeostasis1145-54tnIndividual neurons display characteristic firing patterns determined by the number and kind of ion channels in their membranes. We describe experimental and computational studies that suggest that neurons use activity sensors to regulate the number and kind of ion channels and receptors in their membrane to maintain a stable pattern of activity and to compensate for ongoing processes of degradation, synthesis and insertion of ion channels and receptors. We show that similar neuronal and network outputs can be produced by a number of different combinations of ion channels and synapse strengths. This suggests that individual neurons of the same class may each have found an acceptable solution to a genetically determined pattern of activity, and that networks of neurons in different animals may produce similar output patterns by somewhat variable underlying mechanisms.'ZSVolen Center, Brandeis University, Waltham, MA 02454-9110, USA. marder@brandeis.eduMarder, E. Prinz, A. A.@:22335022 0265-9247 Journal Article Review Review, Tutorial BioessayszAnimal *Homeostasis Human Ions/*metabolism Models, Biological Nerve Net/*physiology Neurons/*pathology Synapses/metabolismlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=124479791237150615 4-6 2002Jun-Jul@9Cellular, synaptic and network effects of neuromodulation 479-93All network dynamics emerge from the complex interaction between the intrinsic membrane properties of network neurons and their synaptic connections. Nervous systems contain numerous amines and neuropeptides that function to both modulate the strength of synaptic connections and the intrinsic properties of network neurons. Consequently network dynamics can be tuned and configured in different ways, as a function of the actions of neuromodulators. General principles of the organization of modulatory systems in nervous systems include: (a) many neurons and networks are multiply modulated, (b) there is extensive convergence and divergence in modulator action, and (c) some modulators may be released extrinsically to the modulated circuit, while others may be released by some of the circuit neurons themselves, and act intrinsically. Some of the computational consequences of these features of modulator action are discussed.'ngVolen Center for Complex Systems, Brandeis University, Waltham, MA 02454-9110, USA. kimack@brandeis.edu Marder, E. Thirumalai, V.("22258250 0893-6080 Journal Article Neural Netwlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1237150612526765371 2003 Jan 92,Current compensation in neuronal homeostasis 2-4c(!How do neurons maintain stable intrinsic properties over long periods of time as the channels that govern excitability turn over in the membrane? In this issue of Neuron, MacLean et al. argue that homeostatic regulation of intrinsic activity can occur by an activity-independent mechanism.d'@:Volen Center, Brandeis University, 02454, Waltham, MA, USAMarder, E. Prinz, A. A.p("22415610 0896-6273 Journal Article Neuronlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12526765e ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10947833)HBMeyrand, P. Faumont, S. Simmers, J. Christie, A. E. Nusbaum, M. P.@:Species-specific modulation of pattern-generating circuits4-Animal Cholecystokinin/analysis Crabs Electrophysiology Fluorescent Dyes GABA/analysis Isoquinolines Lobsters/*physiology Nervous System/cytology Neural Pathways Neurons/chemistry/*physiology Oligopeptides/analysis *Periodicity Phylogeny Species Specificity Stomach/innervation Support, Non-U.S. Gov'tCPhylogenetic comparison can reveal general principles governing the organization and neuromodulation of neural networks. Suitable models for such an approach are the pyloric and gastric motor networks of the crustacean stomatogastric ganglion (STG). These networks, which have been well studied in several species, are extensively modulated by projection neurons originating in higher-order ganglia. Several of these have been identified in different decapod species, including the paired modulatory proctolin neuron (MPN) in the crab Cancer borealis [Nusbaum & Marder (1989) J. Neurosci., 9,1501-1599; Nusbaum & Marder (1989), J. Neurosci., 9, 1600-1607] and the apparently equivalent neuron pair, called GABA (gamma-aminobutyric acid) neurons 1 and 2 (GN1/2), in the lobster Homarus gammarus [Cournil et al. (1990) J. Neurocytol., 19, 478-493]. The morphologies of MPN and GN1/2 are similar, and both exhibit GABA-immunolabelling. However, unlike MPN, GN1/2 does not contain the peptide transmitter proctolin. Instead, GN1/2, but not MPN, is immunoreactive for the neuropeptides related to cholecystokinin (CCK) and FLRFamide. Nonetheless, GN1/2 excitation of the lobster pyloric rhythm is similar to the proctolin-mediated excitation of the crab pyloric rhythm by MPN. In contrast, GN1/2 and MPN both use GABA but produce opposite effects on the gastric mill rhythm. While MPN stimulation produces a GABA-mediated suppression of the gastric rhythm [Blitz & Nusbaum (1999) J. Neurosci., 19, 6774- 6783], GN1/2 activates or enhances gastric rhythmicity. These results highlight the care needed when generalizing neuronal organization and function across related species. Here we show that the 'same' neuron in different species does not contain the same neurotransmitter complement, nor does it exert all of the same effects on its postsynaptic targets. Conversely, a different transmitter phenotype is not necessarily associated with a qualitative change in the way that a modulatory neuron influences target network activity.'Laboratoire de Neurobiologie des Reseaux, Universite de Bordeaux I & CNRS UMR 5816, Talence, France. p.meyrand@lnr.u-bordeaux.fr10947833Eur J Neurosci 20001272585-96.^ntials/*physiology Animal90131242Mulloney, B. Hall, W. M.GABA-ergic neurons in the crayfish nervous system: an immunocytochemical census of the segmental ganglia and stomatogastric systemAnimal Crayfish/*anatomy & histology Ganglia/*cytology GABA/*physiology Neurons/*cytology/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.We used an antiserum directed against gamma-aminobutyric acid (GABA) fixed with glutaraldehyde (Hoskins et al., Cell Tissue Res. 244:243- 252, '86) to label neurons with GABA-like immunoreactivity (GLI) in wholemounts of the stomatogastric ganglion and each segmental ganglion of crayfish, except the brain. Each abdominal ganglion had an average of 63 labeled neurons, or 10% of all their neurons. Each peripheral nerve of each abdominal ganglion except the last contained labeled axons. Within each segment, the first peripheral nerve, N1, had five axons; the second peripheral nerve, N2, had at most four; and the third peripheral nerve, N3, had two. In the last ganglion, N2 had one labeled axon, N3 had two and N6 had two; the other nerves contained no labeled axons. A tabulation of the identified inhibitory neurons in the abdominal ganglia revealed that 40% of these GABA-ergic neurons have been identified. The subesophageal ganglion had many labeled neurons in clusters that formed a repeating pattern; it also had labeled neurons near its dorsal midline. The thoracic ganglia contained more labeled neurons than did the abdominals, but their patterns of labeling were similar. The commissural ganglia contained three clusters of labeled neurons and sent labeled axons to the esophageal ganglion. The esophageal ganglion contained four labeled neurons and many labeled axons. The stomatogastric ganglion contained labeled axon terminals but not labeled neurons.i J Comp NeurolT 1990 291 3e 383-94 Mulloney, B. 19914-Circuit dynamics and the strength of synapses Curr Biol1t3'xqDepartment of Biology Emory University 1510 Clifton Road, Atlanta, Georgia 30322, USA. rcalabre@biology.emory.edui f2w*|e(d8{z<6Marder, E. Jorge-Rivera, J.C. Kilman, V. Weimann, J.M. 1997PJPeptidergic modulation of synaptic transmission in a rhythmic motor system Advances in Organ Biology JAI Press, Inc.k2213-233 ("Marder, E. Kopell, N. Sigvardt, K. 1997@9How computation aids in understanding biological networks >8Stein, P.S.G. Grillner, S. Selverston, A.I. Stuart, D.G.*#Neuron, Networks and Motor Behavior  Cambridge, MAM  MIT Pressl139-160 XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9530490 Marder, E.4-From biophysics to models of network functionivpAnimal *Biophysics *Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.ZTNeurons and synapses display a rich range of time-dependent processes. Which of these are critical to understanding specific integrative functions in the brain? Computational methods of various kinds are used to understand how systems of neurons interact to produce behavior. However, these models often assume that neuronal dynamics and synaptic strengths are fixed. This review presents some recent models that illustrate that short-term synaptic plasticity mechanisms such as facilitation and depression can have important implications for network function. Other features of synaptic transmission such as multi- component synaptic potentials, cotransmission, and neuromodulation with obvious potential computational implications are presented. These examples illustrate that synaptic strength and intrinsic properties in networks are continuously varying on numerous time scales as a function of the temporal patterns of activity in the network. Thus, both firing frequency of the neurons in a circuit, and the modulatory environment determine the intrinsic and synaptic properties that produce behavior.'f_Volen Center, Brandeis University, Waltham, Massachusetts 02254, USA. marder@volen.brandeis.edu9530490 1998Annu Rev Neuroscim21 25-45s Using Smart Source Parsing Marder, E.D>Electrical synapses: beyond speed and synchrony to computationhbAnimal Electrophysiology Neurons/*physiology Synapses/*physiology Synaptic Transmission/physiologyF@Classically, electrical synapses were thought only to increase the speed and synchrony of neural activity, but recent results suggest that rectifying electrical synapses can act as coincidence detectors, and regulation of the strength of other electrical synapses can enhance oscillatory or asynchronous neural activity.'^XBiology Department, MS 013, Brandeis University, Waltham, Massachusetts 02454-9110, USA.9811596zhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9811596 http://www.biomednet.com/article/bb8v04 Curr Biol 1998822R795-7.XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9928315>8Marder, E. Manor, Y. Nadim, F. Bartos, M. Nusbaum, M. P.Frequency control of a slow oscillatory network by a fast rhythmic input: pyloric to gastric mill interactions in the crab stomatogastric nervous systemAnimal Crabs Ganglia, Invertebrate/cytology/physiology Motor Neurons/*physiology Nervous System Physiology *Periodicity Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.oThe stomatogastic nervous system of the crab, Cancer borealis, produces a slow gastric mill rhythm and a fast pyloric rhythm. When the gastric mill rhythm is not active, stimulation of the modulatory commissural ganglion neuron 1 (MCN1) activates a gastric mill rhythm in which the lateral gastric (LG) neuron fires in antiphase with interneuron 1 (Int1). We present theoretical and experimental data that indicate that the period of the MCN1 activated gastric mill rhythm depends on the strength and time course of the MCN1 evoked slow excitatory synaptic potential (EPSP) in the LG neuron, and on the strength of inhibition of Int 1 by the pacemaker of the pyloric network. This work demonstrates a new mechanism by which a slow network oscillator can be controlled by a much faster oscillatory neuron or network and suggests that modulation of the slow oscillator can occur by direct action on the neurons and synapses of the slow oscillator, or indirectly by actions on the fast oscillator and its synaptic connection with the slow oscillator.n'|vVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02254, USA. Marder@volen.brandeis.edu9928315cAnn N Y Acad Sci 1998 860l226-38. ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10068214e Marder, E. Pearson, K. G.nB;Editorial overview: motor control from molecules to bedside Animal Human Models, Biological Motor Activity/*physiology Movement Disorders/physiopathology/therapy Neurotransmitters/physiology Sensation/physiology10068214Curr Opin Neurobiol 199886 693-6.\UMarder, E. Golowasch, J. Richards, K. S. Soto-Trevino, C. Miller, W. L. Abbott, L. F.n 199981Self-assembly of oscillatory neurons and networks $Mira, M. Sanchez-Andres, J. V.0)Foundations and tools for neural modelingV Berlin Springer-Verlag 1606 1-11 Marder, E. Richards, K. S.XRDevelopment of the peptidergic modulation of a rhythmic pattern generating networkAnimal Ganglia, Invertebrate/physiology Lobsters/*physiology Motor Activity/physiology Nerve Net/*physiology Neuropeptides/*physiology Periodicity Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The stomatogastric ganglion (STG) of adult lobsters and crabs receives dense aminergic and peptidergic projections. The neuropeptides are found in sensory neurons and in descending interneurons that modulate the output of the rhythmic central pattern generating networks in the STG. We describe the presence of these peptidergic projections in the adult Homarus americanus, and the effects of some of these neuropeptides on the motor patterns of the adult STG. We describe the developmental acquisition of these neuropeptides during embryonic and larval times and demonstrate that the immature STG networks are already sensitive to a variety of neuromodulators.'Volen Center and Biology Department, MS 013, Brandeis University, 415 South Street, Waltham, MA 02454, USA. marder@brandeis.edu10612696http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10612696 http://www.elsevier.com:80/cgi-bin/cas/tree/store/bres/cas_sub/browse/browse.cgi?year=1999&volume=848&issue=1-2&aid=19088 Brain Res 1999 848 1-2 35-44.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11240277E Marder, E.Motor pattern generationAnimal Central Nervous System/cytology/*physiology Motor Neurons/*physiology Movement/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.gpjRecent work on the circuits that generate rhythmic movements illustrates the role of cotransmitter complement in motor pattern selection and demonstrates that many principles first established in invertebrates also hold in vertebrates. Major new areas of investigation include the development of central pattern generating networks, and the use of mouse mutants.'NGVolen Center, MS 013, Brandeis University, Waltham, MA 02454-9110, USA.D11240277Curr Opin Neurobiol0 2000106- 691-8. P80036452"Miller, J. P. Selverston, A.TNRapid killing of single neurons by irradiation of intracellularly injected dyeleCell Survival/drug effects Dyes/toxicity Histological Techniques Human Lobsters Neurons/*drug effectss&A simple technique for rapidly killing all or part of single neurons consists of filling the cell with Lucifer Yellow CH and irradiating all or part of it with intense blue light. Such treatment kills the irradiated part of the cell within a few minutes. Adjacent cells are not affected.eSciencet 1979 206s 4419 702-4c Miller, J.P. 1980RKMechanisms underlying pattern generation in lobster stomatogastric ganglion  San Diego University of California Ph.D.83111098&Miller, J. P. Selverston, A. I.IMechanisms underlying pattern generation in lobster stomatogastric ganglion as determined by selective inactivation of identified neurons. IV. Network properties of pyloric systempAnimal Ganglia/anatomy & histology/*physiology Interneurons/physiology Lobsters/*physiology Motor Neurons/*physiology Periodicity Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologyo1. In three preceding papers in this series (6, 33, 45), the functional roles, intrinsic cellular properties, and synaptic connections of identified neurons in the lobster stomatogastric ganglion were investigated using the dye-sensitized photoinactivation technique. In this paper, we investigate the network properties of the pyloric system. 2. The relative strengths of the synaptic interactions between all possible motor neuron pairs were measured from the neuronal cell bodies. 3. Experiments were performed to determine the minimal subset of the pyloric neurons that could generate rhythmic activity due to network interactions alone. With the endogenously bursting anterior burster (AB) cell excluded from consideration, the minimum number of elements was found to be two. These two elements behaved as a classical "half-center" oscillator when their overall activity levels were appropriately adjusted. 4. Two cells in the commissural ganglia supply the pyloric system with rhythmic excitatory input phase locked to ongoing pyloric activity. The rhythmicity of that input is shown to be functionally irrelevant. The inputs can exert their effects on pyloric system activity through tonic firing. 5. A qualitative explanation of three important aspects of the pyloric motor pattern is presented, based on the intrinsic properties of pyloric neurons and the systematic properties of the network they form. The existence of the pattern results from oscillatory membrane properties of the individual neurons in combination with the multiple reciprocally inhibitory interactions within the network. The phase relationships derive from the synaptic connectivity and depend on relative synaptic strengths, postinhibitory rebound, rebound delay, and the kinetics of the plateau and bursting pacemaker-potential generation mechanisms. The overall pattern frequency is determined by the AB interneuron via its intrinsic oscillatory behavior and strong synapses with the rest of the pyloric neurons.tJ Neurophysiol 1982486c1416-32083111096&Miller, J. P. Selverston, A. I.IMechanisms underlying pattern generation in lobster stomatogastric ganglion as determined by selective inactivation of identified neurons. II. Oscillatory properties of pyloric neuronsAnimal Electric Stimulation Ganglia/*physiology Interneurons/physiology Lobsters/*physiology *Movement Periodicity Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.1. The motor program controlling the rhythmic movements of the pyloric region of the lobster stomach is generated by neurons in the stomatogastric ganglion. Neurons within this "pyloric network" were tested for their ability to generate bursting pacemaker potentials (BPPs). For these experiments, each neuron to be tested was isolated from other cells within the stomatogastric ganglion by use of the dye- sensitized photoinactivation technique. All extraganglionic inputs to the stomatogastric ganglion were blocked. 2. Only one cell in the pyloric network, the anterior burster (AB) cell, continued to generate BPPs when isolated in this manner. The AB cell is also the only interganglionic interneuron in the pyloric network. 3. Two other neurons that were previously thought to be endogenous bursters, the pyloric dilator (PD) cells, fired tonically when isolated from synaptic input. However, tonic stimulation of the stomatogastric nerve elicited BPP generation in the PD cells. These membrane-potential oscillations were generated for periods of up to a minute following cessation of the stimulus. 4. Stimulation of the stomatogastric nerve also elicited BPP generation in two other pyloric cell types: the ventricular dilator (VD) and lateral pyloric (LP) cells. 5. A reduced subset of the pyloric network was obtained by photoinactivation of several cells, including the spontaneously oscillatory AB interneuron. When inputs to this reduced network were blocked, all pattern generation ceased. A short stimulus to the stomatogastric nerve induced an episode of coordinated patterned activity from these cells. Thus, BPP production contributes to the production and stability of the pyloric motor program.J Neurophysiol 1982486t1378-91f$Miller, J.P. Selverston, A.I. 1985PINeural mechanisms for the production of the lobster pyloric motor pattern "Selverston, A.I. Moulins, M.("Model Neural Networks and Behavior New York  Plenum Press 37-48l Miller, J.P. 1987Pyloric mechanisms "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag109-136 &x  12590348 2131 2003 FebDevelopment of the nervous system in the quot;head" of Limulus polyphemus (Chelicerata: Kiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata  9-17We investigated brain development in the horseshoe crab Limulus polyphemus and several other arthropods via immunocytochemical methods, i.e. antibody stainings against acetylated alpha-tubulin and synapsin. According to the traditional view, the first appendage-bearing segment in chelicerates (the chelicerae) is not homologous to the first appendage-bearing segment of mandibulates (first antenna, deutocerebrum) but to the segment of the second antenna (tritocerebrum) or the intercalary segment in hexapods and myriapods. Accordingly, the segment of the deutocerebrum in chelicerates would be completely reduced. The main arguments for this view are: (1) the postoral origin of the cheliceral ganglion, (2) a poststomodaeal commissure, and (3) a connection of the cheliceral ganglion to the stomatogastric system. Our data show that these arguments are not convincing. During the development of horseshoe crabs there is no evidence for a former additional segment in front of the chelicerae. Instead, comparison of the brain structure (neuropil ring) between chelicerates, crustaceans and insects shows remarkable similarities. Furthermore, the cheliceral commissure in horseshoe crabs runs mainly praestomodaeal, which would be unique for a tritocerebral commissure. An unbiased view of the developing nervous system in the "head" of chelicerates, crustaceans and insects leads to a homologisation of the cheliceral segment and that of the (first) antenna (= deutocerebrum) of mandibulates that is also congruous to the interpretation of the Hox gene expression patterns. Thus, our data provide morphological evidence for the existence of a chelicerate deutocerebrum.'Institut fur Biologie, Vergleichende Zoologie, Humboldt-Universitat zu Berlin, Philippstr. 13, 10115, Berlin, Germany, Beate.Mittmann@rz.hu-berlin.deMittmann, B. Scholtz, G.("22477956 0949-944x Journal ArticleDev Genes Evollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12590348xrMizrahi, A. Dickinson, P. S. Kloppenburg, P. Fenelon, V. Baro, D. J. Harris-Warrick, R. M. Meyrand, P. Simmers, J.Long-term maintenance of channel distribution in a central pattern generator neuron by neuromodulatory inputs revealed by decentralization in organ culture/*#Animal Antibodies/pharmacology Biological Clocks/drug effects/*physiology Cell Membrane/metabolism Digestive System/innervation Ganglia, Invertebrate/cytology/drug effects/metabolism In Vitro Ion Channels/antagonists & inhibitors/*metabolism Lobsters Motor Neurons/drug effects/*metabolism Nerve Net/cytology/drug effects/metabolism Neurites/metabolism Neurotransmitters/*metabolism Patch-Clamp Techniques Periodicity Potassium/metabolism Potassium Channel Blockers Potassium Channels/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.a>7Organotypic cultures of the lobster (Homarus gammarus) stomatogastric nervous system (STNS) were used to assess changes in membrane properties of neurons of the pyloric motor pattern-generating network in the long-term absence of neuromodulatory inputs to the stomatogastric ganglion (STG). Specifically, we investigated decentralization-induced changes in the distribution and density of the transient outward current, I(A), which is encoded within the STG by the shal gene and plays an important role in shaping rhythmic bursting of pyloric neurons. Using an antibody against lobster shal K(+) channels, we found shal immunoreactivity in the membranes of neuritic processes, but not somata, of STG neurons in 5 d cultured STNS with intact modulatory inputs. However, in 5 d decentralized STG, shal immunoreactivity was still seen in primary neurites but was likewise present in a subset of STG somata. Among the neurons displaying this altered shal localization was the pyloric dilator (PD) neuron, which remained rhythmically active in 5 d decentralized STG. Two-electrode voltage clamp was used to compare I(A) in synaptically isolated PD neurons in long-term decentralized STG and nondecentralized controls. Although the voltage dependence and kinetics of I(A) changed little with decentralization, the maximal conductance of I(A) in PD neurons increased by 43.4%. This increase was consistent with the decentralization-induced increase in shal protein expression, indicating an alteration in the density and distribution of functional A-channels. Our results suggest that, in addition to the short-term regulation of network function, modulatory inputs may also play a role, either directly or indirectly, in controlling channel number and distribution, thereby maintaining the biophysical character of neuronal targets on a long-term basis.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and Centre National de la Recherche Scientifique, Talence 33405, France.11549743 J Neurosci 200121187331-9.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11549743 http://www.jneurosci.org/cgi/content/full/21/18/7331 http://www.jneurosci.org/cgi/content/abstract/21/18/7331Mocquard, M.F. 1983.(L'estomac des Crustaces podaphthalmairesAnn Sci Nat Zool16 1-311Morris, J. Maynard, D.M. 1970JDRecordings from the stomatogastric nervous system in intact lobstersComp Biochem Physiol33969-974nghttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/17/15/5956.97368249"Morris, L. G. Hooper, S. L.wMuscle response to changing neuronal input in the lobster (Panulirus interruptus) stomatogastric system: spike number- versus spike frequency-dependent domainsyAnimal Electromyography Gastrointestinal System/*physiology Lobsters Motor Neurons/*physiology Muscle Contraction/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.sWe aimed to determine the neuronal parameters controlling the contraction of slowly contracting, non-twitch ("tonic") muscles driven by rhythmic neuronal activity. These muscles are almost completely absent in mammals but are common in lower vertebrates and invertebrates. Slow muscles are often believed to function primarily in tonic motor patterns. However, previous research and data presented here indicate that slow muscles are also driven by rhythmic neuronal inputs. In rapidly contracting "twitch" muscles, motor unit force is believed to be primarily determined by motor neuron spike frequency. What determines slow muscle output is less well understood. We present a simple model that suggests that when motor neuron burst duration is brief compared with muscle summation time, spike number, not spike frequency, determines slow muscle contraction amplitude. We present analyses that distinguish between spike number and spike frequency dependence in two slow muscles in the lobster stomatogastric system. Our analysis shows that, functionally, one muscle is spike number dependent, whereas the other is primarily spike frequency dependent. Thus, both of these parameters can determine slow muscle output. To predict the movements elicited by neuronal activity in preparations in which slow muscles are common, it may be necessary to determine spike number versus spike frequency dependence for each muscle. Spike number dependence couples motor neuron burst duration and spike frequency in that changing either parameter alone alters spike number (and hence muscle contraction amplitude). Neural networks innervating spike number- dependent muscles may therefore have specific properties to compensate for the complexity intrinsic to spike number coding. J Neurosci 199717155956-71n h lfhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/18/9/343398213720"Morris, L. G. Hooper, S. L.Muscle response to changing neuronal input in the lobster (Panulirus interruptus) stomatogastric system: slow muscle properties can transform rhythmic input into tonic output>8Action Potentials/physiology Animal Ganglia, Invertebrate/physiology Linear Models Lobsters/*physiology Muscle Contraction/physiology Muscle Fibers, Slow-Twitch/physiology Neuromuscular Junction/physiology Neurons/physiology Periodicity Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.Slow, non-twitch muscles are widespread in lower vertebrates and invertebrates and are often assumed to be primarily involved in posture or slow motor patterns. However, in several preparations, including some well known invertebrate "model" preparations, slow muscles are driven by rapid, rhythmic inputs. The response of slow muscles to such inputs is little understood. We are investigating this issue with a slow stomatogastric muscle (cpv1b) driven by a relatively rapid, rhythmic neural pattern. A simple model suggests that as cycle period decreases, slow muscle contractions show increasing intercontraction temporal summation and at steady state consist of phasic contractions overlying a tonic contracture. We identify five components of these contractions: total, average, tonic, and phasic amplitudes, and percent phasic (phasic amplitude divided by total amplitude). cpv1b muscle contractions induced by spontaneous rhythmic neural input in vitro consist of phasic and tonic components. Nerve stimulation at varying cycle periods and constant duty cycle shows that a tonic component is always present, and at short periods the muscle transforms rhythmic input into almost completely tonic output. Varying spike frequency, spike number, and cycle period show that frequency codes total, average, and tonic amplitudes, number codes phasic amplitude, and period codes percent phasic. These data suggest that tonic contraction may be a property of slow muscles driven by rapid, rhythmic input, and in these cases it is necessary to identify the various contraction components and their neural coding. Furthermore, the parameters that code these components are interdependent, and control of slow muscle contraction is thus likely complex.o J Neurosci 1998189n3433-42.(Morris, L. G. Thuma, J. B. Hooper, S. L.f_Muscles express motor patterns of non-innervating neural networks by filtering broad-band inputTNAction Potentials/physiology Animal Electric Stimulation Heart/innervation/physiology Lobsters/cytology/*physiology Motor Neurons/cytology/*physiology Muscle Contraction/*physiology Muscles/*innervation/*physiology Nerve Net/cytology/*physiology Neuromuscular Junction/cytology/physiology Stomach/innervation/physiology Weight-BearingWe describe three slow muscles that responded to low-frequency modulation of a high-frequency neuronal input and, consequently, could express the motor patterns of neural networks whose neurons did not directly innervate the muscles. Two of these muscles responded to different frequency components present in the same input, and as a result each muscle expressed the motor pattern of a different, non- innervating, neural network. In an analogous manner, the distinct dynamics of the multiple intracellular processes that most cells possess may allow each process to respond to, and hence differentiate among, specific frequency ranges present in broad-band input.'Department of Physiology and Biophysics, Mt. Sinai Medical School, Box 1218, 1 Gustave L. Levy Place, New York, New York 10029, USA.10700256 Nat Neurosci 200033245-50. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10700256 http://www.nature.com/cgi-taf/DynaPage.taf?file=/neuro/journal/v3/n3/full/nn0300_245.html http://www.nature.com/cgi-taf/DynaPage.taf?file=/neuro/journal/v3/n3/abs/nn0300_245.html"Morris, L. G. Hooper, S. L.~xMechanisms underlying stabilization of temporally summated muscle contractions in the lobster (Panulirus) pyloric system.(Animal Electric Stimulation In Vitro Isotonic Contraction/*physiology Lobsters *Models, Biological Muscle Contraction/*physiology Muscle Tonus/physiology Nerve Net/*physiology Periodicity Pylorus/innervation/*physiology Reaction Time/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Muscles are the final effectors of behavior. The neural basis of behavior therefore cannot be completely understood without a description of the transfer function between neural output and muscle contraction. To this end, we have been studying muscle contraction in the well-investigated lobster pyloric system. We report here the mechanisms underlying stabilization of temporally summating contractions of the very slow dorsal dilator muscle in response to motor nerve stimulation with trains of rhythmic shock bursts at a physiological intraburst spike frequency (60 Hz), physiological cycle periods (0.5-2 s), and duty cycles from 0.1 to 0.8. For temporal summation to stabilize, the rise and relaxation amplitudes of the phasic contractions each burst induces must equalize as the rhythmic train continues. Stabilization could occur by changes in rise duration, rise slope, plateau duration, and/or relaxation slope. We demonstrate a generally applicable method for quantifying the relative contribution changes in these characteristics make to contraction stabilization. Our data show that all characteristics change as contractions stabilize, but their relative contribution differs depending on stimulation cycle period and duty cycle. The contribution of changes in rise duration did not depend on period or duty cycle for the 1-, 1.5-, and 2-s period regimes, contributing approximately 30% in all cases; but for the 0.5-s period regime, changes in rise duration increased from contributing 25% to contributing 50% as duty cycle increased from 0.1 to 0.8. At all cycle periods decreases in rise slope contributed little to stabilization at small duty cycles but increased to contributing approximately 80% at high duty cycles. The contribution of changes in plateau duration decreased in all cases as duty cycle increased; but this decrease was greater in long cycle period regimes. The contribution of changes in relaxation slope also decreased in all cases as duty cycle increased; but for this characteristic, the decrease was greatest in fast cycle period regimes, and in these regimes at high duty cycles these changes opposed contraction stabilization. Exponential fits to contraction relaxations showed that relaxation time constant increased with total contraction amplitude; this increase presumably underlies the decreased relaxation slope magnitude seen in high duty cycle, fast cycle period regimes. These data show that changes in no single contraction characteristic can account for contraction stabilization in this muscle and suggest that predicting muscle response in other systems in which slow muscles are driven by rapidly varying neuronal inputs may be similarly complex.'LEDepartment of Biology, Emory University, Atlanta, Georgia 30322, USA.11152725J Neurophysiol 2001851254-68.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11152725 http://www.jn.physiology.org/cgi/content/full/85/1/254 http://www.jn.physiology.org/cgi/content/abstract/85/1/254 :q0,Neurosecretory Systems/*chemistry/embryology("Neurosecretory Systems/*physiology$!Neurosecretory Systems/*secretion<6Neurosecretory Systems/anatomy & histology/*physiologyNeurotoxins/pharmacologyNeurotransmitters Neurotransmitters/*analysis,&Neurotransmitters/*analysis/immunology Neurotransmitters/*metabolism0*Neurotransmitters/*metabolism/pharmacology$Neurotransmitters/*pharmacology Neurotransmitters/*physiology Neurotransmitters/*secretion Neurotransmitters/analysis(%Neurotransmitters/analysis/physiology<6Neurotransmitters/antagonists & inhibitors/*metabolism84Neurotransmitters/chemistry/metabolism/*pharmacology,'Neurotransmitters/immunology/metabolism<6Neurotransmitters/isolation & purification/*physiology Neurotransmitters/metabolism,(Neurotransmitters/metabolism/*physiology,'Neurotransmitters/metabolism/physiology$Neurotransmitters/pharmacology Neurotransmitters/physiology NickelNickel/*pharmacology("Nicotine/*antagonists & inhibitorsNicotine/metabolismNifedipine/pharmacology$ Nitric Oxide Donors/pharmacologyNitric Oxide/*metabolismNitric Oxide/*physiology$Nitric-Oxide Synthase/analysis Nitroprusside/pharmacologyNonlinear Dynamics4.Nucleic Acid Synthesis Inhibitors/pharmacologyOctopamine/pharmacology(#Octopamine/pharmacology/*physiologyOctopamine/physiologyOligochaeta/*chemistry OligopeptidesOligopeptides/*analysisOligopeptides/*metabolism,&Oligopeptides/*metabolism/pharmacology Oligopeptides/*pharmacologyOligopeptides/*physiologyOligopeptides/analysis0-Oligopeptides/analysis/immunology/*metabolism40Oligopeptides/chemistry/metabolism/*pharmacology(#Oligopeptides/immunology/metabolismOligopeptides/metabolism,&Oligopeptides/metabolism/*pharmacology($Oligopeptides/metabolism/*physiology(%Oligopeptides/metabolism/pharmacology Oligopeptides/pharmacology,&Oligopeptides/pharmacology/*physiologyOligopeptides/physiology Oocytes Oocytes/cytology/metabolismOocytes/physiology Open Reading Frames/genetics Organ Culture Oscillation Oscillations OscillometryOuabain/pharmacologyOxotremorine/pharmacologyOxygen/*pharmacokineticsOxygen/*pharmacology$Oxygen/*pharmacology/physiology Pacemaker PalinuridaePalinuridae/*physiology$ Palinuridae/genetics/*physiology83Parasympathetic Nervous System/cytology/*physiology$ Parasympatholytics/*pharmacology$Parasympatholytics/pharmacology$!Parasympathomimetics/pharmacologyPatch-Clamp Techniques,'Patch-Clamp Techniques/*instrumentation$Patch-Clamp Techniques/methods40Penicillamine/analogs & derivatives/pharmacology Peptide Fragments/*analysisHBPeptide Fragments/administration & dosage/*pharmacology/physiology Peptide Fragments/analysis(%Peptide Fragments/genetics/metabolism$Peptide Hydrolases/pharmacology$Peptides/*immunology/metabolismPeptides/*physiologyPeptides/analysis$Peptides/immunology/physiology$!Peptides/pharmacology/*physiology0,Pericardium/growth & development/*metabolismPericardium/metabolism Periodicity0+Peripheral Nerves/metabolism/ultrastructure Peripheral Nerves/physiology(#Peripheral Nervous System/chemistry@;Peripheral Nervous System/embryology/metabolism/*physiology PeristalsisPeristalsis/drug effects Pertussis Toxins/pharmacologyphase maintenance Phenotype Phospholipase C/metabolismPhosphorylation Phosphorylcholine/metabolism0-Photoreceptors/drug effects/radiation effects PhylogenyPhysical StimulationPicrotoxin/*pharmacologyPicrotoxin/pharmacologyPilocarpine/pharmacology6@ 530474133 1979 AughbComplex motor neurone in crustacea: three axonal spike initiating zones in three different ganglia 231-6(!Moulins, M. Vedel, J. P. Nagy, F.("80121174 0304-3940 Journal Article Neurosci LettuAction Potentials Animal Axons/physiology Electric Stimulation Ganglia/cytology/*physiology Motor Activity/physiology Motor Neurons/*physiology Nephropidae/*physiology Neural Conduction Periodicityjchttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=530474Moulins, M. Nagy, F. 1981Participation of an unpaired motor neurone in the bilaterally organized oesophageal rhythm in the lobsters Jasus lalandii and Panulirus vulgarisiky~ J Exp Biol90205-230sMoulins, M. Nagy, F. 1981@9Complex integrative functions in crustacean motor neurons Adv Physiol23385-406r83032545Moulins, M. Cournil, I.dvpAll-or-none control of the bursting properties of the pacemaker neurons of the lobster pyloric pattern generatorAfferent Pathways/physiology Animal Calcium/metabolism Female Ganglia/*physiology Lobsters/*physiology Male Membrane Potentials Motor Neurons/physiology Neurons/physiology Pylorus/*innervation Support, Non-U.S. Gov't *Synaptic TransmissionIn Crustacea the central pattern generator for the pyloric motor rhythm (filtration to the midgut) is known to be located within the stomatogastric ganglion (STG); its cycling activity is known to be organized by three endogenous burster neurons acting as pacemakers and driving 11 follower neurons. In Homarus, recordings from the isolated stomatogastric nervous system (Fig. 1) indicate that (1) the pyloric output can be generated only when the STG is afferented (i.e., connected to the more rostral oesophageal and commissural ganglia) (Fig. 2) and (2) the deafferentation of the STG results in a complete loss of the bursting properties of the pacemaker neurons (Fig. 4). Manipulation of the STG inputs responsible for unmasking the properties of the pacemakers strongly suggests that (1) they are not phasic inputs (Fig. 5) and (2) they are long-term acting inputs (Fig. 6). These results provide evidence for a neural all-or-none control of the bursting properties of the pacemaker neurons of a motor pattern generator. J Neurobiol 1982135 447-58Moulins, M. Nagy, F. 1983TMControl of integration by extrinsic inputs in the crustacean pyloric circuitss J Physioln78739-748 Moulins, M. 1985:3Rhythm generation in an invertebrate nervous system & Bianchi, A.L. Devanit-Saubie, M.0*Neurogenesis of Central Respiratory Rhythm  M.T.P. Press 33-40oMoulins, M. Nagy, F. 1985`ZExtrinsic inputs and flexibility in the motor output of the lobster pyloric neural network Selverston, A.I.("Model Neural Networks and Behavior New York  Plenum Press 49-68c Moulins, M. 1988*#Les petits cerveaux des invertebres Kordon, C. Degos, L.,&Communication Cellulaire et Pathologie London John Libbey Inserm155-16172229732"Mulloney, B. Selverston, A.ZSAntidromic action potentials fail to demonstrate known interactions between neurons*Action Potentials Animal Electrophysiology Ganglia/physiology In Vitro Lobsters Motor Neurons/physiology Muscles/innervation Neural Inhibition Neurons/*physiology Stomach/innervation Synapses/physiology Scienceb 1972 177 43 69-72 $Mulloney, B. Selverston, A.I.g 1974ngOrganization of the stomatogastric ganglion in the spiny lobster. I. Neurons driving the lateral teethJ Comp Physiol91 1-32$Mulloney, B. Selverston, A.I.s 1974{Organization of the stomatogastric system in the spiny lobster. III. Coordination of the two subsets of the gastric systemJ Comp Physiol91 53-78l Mulloney, B. 1977|uOrganization of the stomatogastric ganglion of the spiny lobster. V. Coordination of the gastric and pyloric systemsJ Comp Physiol 122227-240820696960)Mulloney, B. Perkel, D. H. Budelli, R. W.PIMotor-pattern production: interaction of chemical and electrical synapsesl Animal Dendrites/physiology Lobsters Membrane Potentials Models, Neurological Motor Activity/*physiology *Neural Inhibition Neurons/physiology Neurotransmitters/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/physiology *Synaptic Transmission A pair of neurons exhibiting postinhibitory rebound, if connected through reciprocally inhibitory chemical synapses, will exhibit a stable pattern of alternating bursts. If two such oscillating pairs, of similar but not identical properties are connected by means of an electrical synapse and an inhibitory chemical synapse between two neurons, one in each pair, the burst patterns may drift, may lock in synchrony, may entrain in antiphase, may entrain at an intermediate phase, or may be suppressed in the inhibited pair. The behavior depends on the strengths of the chemical and electrical coupling as well as on the degree of depression at the chemical synapse. There relationships of the motor patterns are illustrated quantitatively through theoretical calculations. Brain Res 1981 2291 25-33 Mulloney, B. 1987Neural circuits "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag 57-75 n|$ ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11240276Nadim, F. Manor, Y.a@9The role of short-term synaptic dynamics in motor controlDuring the past few years, much attention has been given to the role of short-term synaptic plasticity, in particular depression and facilitation, in sculpting network activity. A recent study shows that synaptic depression in rhythmic motor networks could switch the control of network frequency from intrinsic neuronal properties to the synaptic dynamics. Short-term synaptic plasticity is also involved in the stabilization and reconfiguration of motor circuits and in the initiation, maintenance and modulation of motor programs.'Department of Mathematical Sciences, New Jersey Institute of Technology and Department of Biological Sciences, Rutgers University, University Heights Newark, 07102, Newark, NJ, USA11240276Curr Opin Neurobiol 2000106683-90."Nadim, F. Manor, Y. Bose, A. 200160Control of network output by synaptic depressionNeurocomputing 38-40b 1-4f781-787o,%Oscillations; Inhibition; Bistability In a network of an excitatory and an inhibitory neuron, depression in the inhibitory synapse can produce two distinct oscillatory regimes. In one regime, the network has a short period cell-dominated solution; in the other regime, the solution has much longer period and is synapse-dominated. These regimes overlap to produce an interval of bistability. Neuromodulatory input that targets one of multiple parameters in the network can switch the network control between the intrinsic properties of cells and the dynamics of the synapses./'81Department of Mathematical Sciences, Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, Newark, NJ 07102, USA Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA Life Sciences Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel$://000183514300014 ISI:000183514300014*NeurocomputingjNShort-term synaptic dynamics promote phase maintenance in multi-phasic rhythms"79-87B&Nadim, F. Booth, V. Bose, A. Manor, Y.synaptic dynamics phase maintenance multi-phasic rhythms interruptus stomatogastric ganglion intersegmental coordination pyloric pattern lobster crab locomotion behavior'2Nadim, F. New Jersey Inst Technol, Dept Math Sci, Newark, NJ 07102 USA New Jersey Inst Technol, Dept Math Sci, Newark, NJ 07102 USA Rutgers State Univ, Dept Sci Biol, Newark, NJ 07102 USA Ben Gurion Univ Negev, Zlotowski Ctr Neurosci, Dept Life Sci, IL-84105 Beer Sheva, IsraelnWe show that in an inhibitory rhythmic network synaptic depression promotes phase constancy. As cycle period increases, the synapse recovers from depression and becomes more effective in delaying the postsynaptic cell. As a result, the delay between the pre- and postsynaptic bursts increases as cycle period increases. We discuss the dependence of the bursting phase of the postsynaptic cell on the strength and kinetics of the depressing synapse. (C) 2003 Elsevier Science B.V. All rights reserved.\?Times Cited: 1 Article English Cited References Count: 14 689vu*Neurocomputing0Elsevier Science Bv 52-4 JUNo 2003Nagy, F. 1981Etude de l'expression d'actrivites motrices rhythmiques organisees par des generateurs paucineuroniques du systeme nerveux stomatogastrique des crustaces decapodes. Bordeaux, France Univerity of Bordeaux I Ph.D.81241612,%Nagy, F. Dickinson, P. S. Moulins, M.NPJRhythmical synaptic control of axonal conduction in a lobster motor neuronAnimal Axons/*physiology Esophagus/innervation Female Lobsters/*physiology Male Motor Neurons/*physiology Nerve Block Neural Conduction Support, Non-U.S. Gov't Synapses/*physiologyJ Neurophysiol 1981456S1109-24h81245886,%Nagy, F. Dickinson, P. S. Moulins, M.ujdModulatory effects of a single neurons on the activity of the pyloric pattern generator in CrustaceaAnimal Crustacea/*physiology Esophagus/innervation Ganglia/physiology Lobsters/physiology Neurons/*physiology Pylorus/innervation/physiology Support, Non-U.S. Gov'tThe firing of a single neuron (named anterior pyloric modulator: APM) of the esophageal ganglion considerably modifies the pyloric rhythm of the rock lobster. These modifications, characterized by a long delay to onset and a long duration, include increased frequency and amplitude of oscillations of the motor neurons, changes in the efficacy of certain synapses within the network, and voltage-dependent modifications of membrane properties of some motor neurons. APM thus seems to be a true modulatory neuron. The APM-provoked changes resemble changes seen in the whole animal, making this a suitable system for an analysis of modulation on several levels.y Neurosci Lett7 1981232a 167-73Nagy, F. Moulins, M. 1981Proprioceptive control of the bilaterally organized rhythmic activity of the oesophageal neuronal network in the Cape lobster Jasus lalandii~ J Exp Biol90231-25184009534 Nagy, F. Dickinson, P. S..Control of a central pattern generator by an identified modulatory interneurone in crustacea. I. Modulation of the pyloric motor outputaAnimal Axons/physiology Digestive System/*innervation Electric Conductivity Female Ganglia/physiology Interneurons/*physiology Lobsters Male Support, Non-U.S. Gov't Synapses/physiologyIn the lobsters Fasus lalandii and Palinurus vulgaris, the rhythmical activity of the pyloric pattern generator of the stomatogastric nervous system is strongly modified by the firing of a single identified interneurone, whose activity we have recorded from the cell body, in vitro. The cell body of this interneurone, the anterior pyloric modulator (APM), is located in the oesophageal ganglion and sends two axons to the stomatogastric ganglion via the inferior oesophageal nerves, the commissural ganglia, the superior oesophageal nerves and the stomatogastric nerve. Firing of neurone APM modifies the activity of all the neurones of the pyloric network, including pacemaker and follower neurones. Its effects are both quantitative (increase in the frequency of the rhythm and in the frequency of spikes within cell bursts) and qualitative (modifications in relative efficacies of the synaptic relationships within the pyloric network, which in turn lead to changes in the phase relationships between the discharges of the neurones). The effects on pyloric activity induced by firing of neurone APM are established slowly (one or two seconds) and are of long duration (ten times the duration of APM's discharge). These modifications most probably involve muscarinic cholinergic receptors. APM's influences on the activity of pyloric neurones appear to be characteristic of a neuromodulatory process and are such that they may be of behavioural significance in the intact animal. J Exp Biol 1983 105t 33-58 Nagy, E. Miller, J.P.  1987Appendix A: Pyloric pattern generation in Panulirus interruptus is terminated by blockade of activity through the stomatogastric nerve*? "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag136-139 rpNagy, F. Moulins, M. 1987Extrinsic inputs "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag205-24288316388,%Nagy, F. Dickinson, P. S. Moulins, M. Control by an identified modulatory neuron of the sequential expression of plateau properties of, and synaptic inputs to, a neuron in a central pattern generatorAction Potentials Animal Electrophysiology Female Interneurons/physiology Lobsters Male Nerve Regeneration Nervous System/*physiology *Nervous System Physiology Neurons/*physiology Stomach/innervation Support, Non-U.S. Gov't Synapses/*physiologytXQRecordings from the lateral gastric (LG) neuron, which forms part of the gastric mill central pattern generator in the red lobster, Palinurus vulgaris, indicate that regenerative membrane properties (plateau properties) and synaptic inputs interact sequentially rather than simultaneously to determine its discharge pattern. LG thus presents a composite discharge, consisting of 2 separate segments of firing and one silent period. The first firing segment depends on regenerative membrane properties; this is the endogenous component, or segment, of LG's discharge. The second firing segment is the result of extrinsic synaptic input, forming the synaptic component of LG's discharge. The relative importance of these 2 components can vary, and thus LG's discharge ranges from one in which LG fires only as a result of its endogenous component to one in which its endogenous component is entirely absent and only the synaptic component underlies action potentials. Activity in an identified modulatory neuron suppresses the endogenous segment and enhances the synaptic segment of LG's discharge. This long-lasting effect in turn changes phase relationships within the gastric mill network and provides mechanisms for producing flexibility in the gastric pattern generator and for ensuring that a specific motor output is generated by a flexible neural network.n J Neurosci 19888n8f2875-86y95016937Nagy, F. Cardi, P.A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. II. Modulatory control of the pyloric CPGhPIAnimal Female Ganglia, Invertebrate/*physiology Gastric Emptying/physiology Laterality/physiology Lobsters/*physiology Male Membrane Potentials/physiology Mouth/*innervation Nerve Net/*physiology Neural Inhibition/*physiology Neurons/physiology Pyloric Antrum/*innervation Support, Non-U.S. Gov't Synaptic Transmission/physiologyl1. In the European rock lobster, Homarus gammarus, two bilaterally symmetrical pairs of commissural neurons, P and commissural pyloric (CP), evoke excitatory postsynaptic potentials in the neurons of the pyloric motor network. The present paper shows that the two commissural neurons also exert a modulatory control over the pyloric network. 2. The P and CP neurons were active during ongoing pyloric rhythms. Ongoing pyloric activity was terminated when the neurons were hyperpolarized to inhibit their firing. 3. When the pyloric network was quiescent, depolarizing either the P or CP neuron induced a robust pyloric rhythm. 4. We studied the actions of the P and CP neurons on individual pyloric neurons isolated in situ from network interactions by a photoinactivation techniques. The P neuron induced oscillatory properties in the pacemaker pyloric dilator (PD) neurons and the motor neuron, ventricular dilator (VD), whereas the CP neuron induced rhythmogenic properties in all the network neurons but VD. Together, the P-CP neurons modulated the entire pyloric network. The modulatory effects of the P-CP neurons did not outlast the duration of their discharge. 5. The P and CP neurons also controlled the firing frequency of all the pyloric neurons. They may, in addition, control phasing of the constrictor neurons discharges, but this effect was state-dependent and occurred only when the pyloric central pattern generator was functioning weakly. Their role in providing flexibility to the network operation appeared relatively limited. 6. We conclude that the P and CP neurons are good candidates for insuring long-term maintenance of pyloric network activity patterns.J Neurophysiol 19947162490-50295016936$Nagy, F. Cardi, P. Cournil, I.A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. I. Pyloric-related neurons in the commissural gangliahNHAnimal Female Ganglia, Invertebrate/*physiology GABA/physiology Interneurons/physiology Laterality/physiology Lobsters/*physiology Male Membrane Potentials/physiology Mouth/*innervation Nerve Net/*physiology Neural Inhibition/*physiology Neurons/physiology Pyloric Antrum/*innervation Support, Non-U.S. Gov't Synapses/physiology  1. Operation of the pyloric neural network in the crustacean stomatogastric ganglion (STG) depends on constant firing of modulatory inputs from anterior ganglia. We have identified two bilaterally symmetrical pairs of these inputs in the commissural ganglia (COGs) of the European rock lobster Homarus gammarus. During operation of the pyloric CPG, they fired in pyloric time, out of phase with the pyloric pacemakers. 2. One of the pair was the commissural pyloric (CP) neuron and the other was homologous to the P neuron described in the spiny lobster Panulirus interruptus. We describe their morphology and location in the COG. The CP neuron projected to the STG via the superior esophageal nerve (son) and the stomatogastric nerve (stn), whereas the P neuron projected via the inferior esophageal nerve (ion) and stn. 3. To determine the total number of commissural neurons projecting to the STG, we used cobalt and Lucifer yellow backfilling from their cut axons in the stn. With the ion cut, there were between 8 to 12 labeled somata in each COG including CP cell body, whereas only 2 somata (including P) were labeled with the son cut. Among these neurons, CP and P appeared to be the only commissural neurons that fired in pyloric time and projected in the STG on the pyloric network. 4. The CP neuron produced monosynaptic excitatory postsynaptic potentials (EPSPs) on the pyloric dilator (PD), lateral pyloric (LP), and inferior cardiac (IC) neurons, whereas the P neuron produced monosynaptic EPSPs on all pyloric motoneurons but IC. The P neuron was gamma-aminobutyric acid immunoreactive, and the P-derived EPSPs in pyloric neurons were reversibly blocked by bicuculline, picrotoxin, and D-tubocurarine. 5. The CP and P neurons were electrically coupled, and modification of membrane potential in either one of them appreciably changed the firing frequency of the coupled neuron. 6. A negative- feedback loop from the pyloric anterior burster (AB) interneuron provoked simultaneous rhythmic inhibitions in the P and CP neurons. Together with the electrical coupling, the rhythmic inhibition contributed to synchronize firing of the two commissural neurons. 7. The following papers in the series of describe the modulatory and rhythmic control exerted by the P and CP neurons over the pyloric pattern generator.J Neurophysiol 19947162477-89 Nakemura, K. Takemoto, T. 19862+Morphology of stomach ossicles in Brachyura$Mem Fac Fish (Kagoshima Univ)351 7-15 l  Nargeot, R.ztLong-lasting reconfiguration of two interacting networks by a cooperation of presynaptic and postsynaptic plasticityztAction Potentials/physiology Animal Digestive System/innervation Electric Stimulation Excitatory Postsynaptic Potentials/*physiology Ganglia, Invertebrate/cytology/physiology In Vitro Lobsters Membrane Potentials/physiology Models, Neurological Nerve Net/cytology/*physiology Neuronal Plasticity/*physiology Neurons/physiology Periodicity Presynaptic Terminals/*physiologyThe functional reconfiguration of central neuronal networks, a phenomenon by which neurons change their participation in network operation, is important for organizing adaptive behaviors. Such reconfiguration can be expressed in a long-lasting manner (hours, days) after a training paradigm. The present study shows that such a long- lasting network reconfiguration requires a cooperation of both presynaptic and postsynaptic modifications in a neuronal interaction between two functionally distinct networks. In isolated preparations of the lobster stomatogastric nervous system, the single ventral dilator (VD) neuron can switch its functional participation from one discrete network (the pyloric network) to another (the cardiac sac network). This switching capability can be long-lasting and can be induced by a sensitizing procedure. A persistent change that was associated with this neuronal switching was found in each of the two networks. First, the intrinsic membrane properties of the VD neuron that allow it to participate spontaneously in the pyloric network are altered. Second, bursting activity is strengthened in the inferior ventricular neurons that both drive cardiac sac network activity and monosynaptically excite the VD neuron in phase with this network activity. Importantly, these changes in intrinsic properties of both presynaptic and postsynaptic neurons are required to allow the VD neuron switching, because expression of either the presynaptic or the postsynaptic change alone did not permit VD neuron switching to occur. These results suggest that a cooperative modification of a discrete network interaction is able to persistently switch the output pattern of a motor neuron as a result of a sensitizing paradigm.'Universite Bordeaux 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5816, Laboratoire de Neurobiologie des Reseaux Batiment Biologie Animale, 33405 Talence Cedex, France. r.nargeot@lnr.u- bordeaux.fr11312313http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11312313 http://www.jneurosci.org/cgi/content/full/21/9/3282 http://www.jneurosci.org/cgi/content/abstract/21/9/3282 J Neurosci 20012193282-94.128325002312 2003 Jun 15d^Voltage-dependent switching of sensorimotor integration by a lobster central pattern generator 4803-8Behavioral adaptations and the underlying neural plasticity may not simply result from peripheral information conveyed by sensory inputs. Central neuronal networks often spontaneously generate neuronal activity patterns that may also contribute to sensorimotor integration and behavioral adaptations. The present study explored a novel form of sensory-induced plasticity by which the resulting changes in motor output depend essentially on the preexisting functional state of an identified neuron of an endogenously active central network. In the isolated lobster stomatogastric nervous system, electrical stimulation of a mechanosensory nerve transiently inactivated rhythmic spike bursting in the lateral pyloric (LP) neuron of the pyloric motor pattern-generating network. Repeated sensory nerve stimulation gradually and long-lastingly strengthened the bursting of the LP neuron to the detriment of sensory-elicited inactivation. This strengthening of pyloric-timed rhythmic activity was enhanced by experimental depolarization of the neuron. Conversely, when the LP neuron was hyperpolarized, the same sensory stimulation paradigm now gradually increased the susceptibility of the pyloric-timed bursting of the network neuron to sensory-elicited inactivation. Modulation of depolarization-activated and hyperpolarization-activated ionic conductances that underlie the intrinsic bursting properties of the LP neuron may contribute via differential voltage-dependent recruitment and effects to the respective adaptive processes. These data therefore suggest a novel state-dependent mechanism by which an endogenously active central network can decrease or increase its responsiveness to the same sensory input.r'Universites Bordeaux 1 et 2, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 5543, Laboratoire de Physiologie et Physiopathologie de la Signalisation Cellulaire, 33076 Bordeaux Cedex, France. r.nargeot@lnr.u-bordeaux.fr Nargeot, R.F("22716500 1529-2401 Journal Article J Neurosci`YAction Potentials/physiology Adaptation, Physiological/physiology Animal Digestive System/innervation Electric Stimulation In Vitro Membrane Potentials/physiology Motor Neurons/*physiology Nerve Net/*physiology *Nervous System Physiology Neuronal Plasticity/physiology Neurons, Afferent/*physiology Palinuridae Patch-Clamp Techniques Periodicityilehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12832500v. Marder19991/ Marder19999 Marder19999 Marder19999 Marder19999# Marder19999Q Marder19999w Marder1999 Marder1999 Marder1999 Marder19999f Marder2000g Marder2000h Marder2000 Marder20000h Marder20000i Marder20000 Marder20010 Marder20012i Marder2001r Marder2001 Marder20011` Marder2001j Marder20011 Marder200228 Marder20020j Marder2002k Marder2002 Marder2002 Marder2002 Marder2002x Marder20022- Marder200337 Marder200327 Marder20030I Marder20030 Marder2003 Marder20032 Marder20032 Marder20030 Marder20030Q Marder20042 Marder2004 Marder20040 Marder2005D Marin1986> Masinovsky1987 Massabuau1996[ Massabuau1998\ Massabuau1999] Massabuau2001 Matly2004 Maynard1970 Maynard1970 Maynard1971 Maynard1971 Maynard1972r Maynard1974 Maynard1974 Maynard1975 Maynard1975 Maynard1975 Maynard19750 Maynard1977 Mayrand19908 Mazzoni1989 McCollum1996z Mecsas19909y Mecsas19939 Meier1990 Meiss1975 Meiss1977 Meiss1977 Mercier1997Y Meseke2002X Meseke20035 Messai19976 Messai1997 Meunier1992 Meyrand1986 Meyrand1987 Meyrand1988} Meyrand1989 Meyrand1989m Meyrand1990n Meyrand1990 Meyrand1991 Meyrand1991 Meyrand1991 Meyrand1992 Meyrand1994 Meyrand1994D Meyrand1995a Meyrand1995O Meyrand1995Q Meyrand1995 Meyrand1996Z Meyrand1998[ Meyrand1998^ Meyrand1998 Meyrand1998 Meyrand1998 Meyrand1998\ Meyrand1999d Meyrand1999e Meyrand1999 Meyrand1999# Meyrand19993 Meyrand19999 Meyrand2000 Meyrand2000] Meyrand20014 Meyrand2001 Meyrand2001) Meyrand2002 Meyrand2004C Miller19766 Miller1979 Miller19809 Miller19801 Miller1982 Miller1982: Miller19821; Miller19831< Miller19831= Miller19831 Miller1985 Miller1987 Miller1987w Miller1999o Miller19999Mittmann2003tMiyatani1986uMiyazaki19919 Mizrahi2000 Mizrahi2001Mocquard1983oMoriarty1983 Morris1970 Morris1997 Morris1998 Morris2000 Morris2001 Morris2003 Mortin1991% Moskowitz1997 Moulins1974 Moulins1977 Moulins1977 Moulins1979 Moulins1980} Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1981 Moulins1982 Moulins1983 Moulins1983k Moulins1984 Moulins1984 Moulins1985 Moulins1985> Moulins1985 Moulins1986? Moulins1986E Moulins1987F Moulins1987 Moulins1987 Moulins1988~ Moulins1988 Moulins1988 Moulins1988 Moulins1988R Moulins1988S Moulins1988 Moulins1989 Moulins1990B Moulins1990G Moulins1990H Moulins1990m Moulins1990n Moulins1990 Moulins1990 Moulins1990P Moulins1990 Moulins1991 Moulins1991{ Moulins1992 Moulins1992h Moulins1993 Moulins1994 Moulins1994 Moulins1994f Moulins1995O Moulins1995Q Moulins1995g Moulins1997Mulloney1972Mulloney1974Mulloney1974Mulloney1974@Mulloney19747Mulloney1977Mulloney1981KMulloney1982LMulloney1982Mulloney1984Mulloney1987Mulloney1990Mulloney1991Mulloney1991 Muren1999P Nadim1997| Nadim1998 Nadim1998# Nadim1999 Nadim1999Q Nadim1999 Nadim1999 Nadim2000N Nadim2001O Nadim2001 Nadim2001L Nadim2003 Nadim2003 Nadim2003 Nadim2004 Nadim2004 Nadim2004p Nagy1974 Nagy19799} Nagy1981 Nagy19819 Nagy19819 Nagy1981 Nagy1981 Nagy1981 Nagy1981| Nagy1983 Nagy19839 Nagy1983 Nagy19859F Nagy19871 Nagy1987 Nagy1987 Nagy1988~ Nagy1988 Nagy1988 Nagy1990B Nagy19900G Nagy19901H Nagy19901 Nagy19909 Nagy19919 Nagy1992r Nagy1994A Nagy19944 Nagy19944 Nagy1994 Nagy1994 Nakanishi2001Nakemura1986 Nargeot2001 Nargeot2003P Nassel19979 Nassel19999 Nassel1999A Nathanson1982d Nemoto1988 Nemoto19900+ Nguyen2000 Nishida1990 Nold20044Nonnotte1990n964197862+Norris, B. J. Coleman, M. J. Nusbaum, M. P.ztPyloric motor pattern modification by a newly identified projection neuron in the crab stomatogastric nervous systemAnimal Crabs/*physiology Ganglia, Invertebrate/*physiology Gastric Emptying/physiology Membrane Potentials/physiology Motor Neurons/*physiology Nerve Net/*physiology Pylorus/*innervation Support, U.S. Gov't, P.H.S. Synaptic Transmission/physiologyvzt1. We have used multiple, simultaneous intra- and extracellular recordings as well as Lucifer yellow dye-fills to identify modulatory commissural neuron 5 (MCN5) and characterize its effects in the stomatogastric nervous system (STNS) of the crab, Cancer borealis. MCN5 has a soma and neuropilar arborization in the commissural ganglion (CoG; Figs. 1 and 2), and it projects through the inferior esophageal nerve (ion) and stomatogastric nerve (stn) to the stomatogastric ganglion (STG; Figs. 1-3). 2. Within the CoGs, MCN5 receives esophageal rhythm-timed excitation and pyloric rhythm-timed inhibition (Fig. 4). Additionally, during the lateral teeth protractor phase of the gastric mill rhythm, the pyloric-timed inhibition of MCN5 is reduced or eliminated. 3. Intracellular stimulation of MCN5 excites the pyloric pacemaker ensemble, including the anterior burster (AB), pyloric dilator (PD), and lateral posterior gastric (LPG) neurons. This produces a faster pyloric rhythm. MCN5 stimulation also inhibits all nonpacemaker pyloric neurons, reducing or eliminating their activity (Figs. 5 and 6A; Tables 1 and 2). After MCN5 stimulation, bursting is enhanced for several cycles in some pyloric neurons when compared with their prestimulus activity (Figs. 5 and 6A; Tables 1 and 2). 4. MCN5 evokes distinct responses from each pyloric pacemaker neuron (Figs. 6- 8). The AB and LPG neurons respond with increased activity. The AB response includes the presence of large amplitude excitatory postsynaptic potentials (EPSPs) that contribute to a depolarization of the trough of its rhythmic oscillations (Fig. 6). LPG responds by exhibiting increased activity that prolongs the duration of its burst beyond that of AB and PD (Fig. 7). In contrast, MCN5 stimulation initially produces decreased PD neuron activity, followed by a slight enhancement of each PD burst (Figs. 7 and 8). PD activity is further enhanced after MCN5 stimulation (Figs. 7 and 8). 5. MCN5-elicited action potentials evoke discrete, constant latency inhibitory postsynaptic potentials (IPSPs) in all nonpacemaker pyloric neurons, including the inferior cardiac (IC), lateral pyloric (LP), pyloric (PY), and ventricular dilator (VD) neurons (Fig. 9). MCN5 activity also inhibits these neurons indirectly, via its excitation of the pacemaker neurons. The pyloric pacemaker neurons synaptically inhibit all four nonpacemaker neurons. 6. The increased activity in the VD neuron, after MCN5 stimulation, is not mimicked by either direct hyperpolarization or by synaptically inhibiting VD via another pathway (Fig. 10). The poststimulation increase in IC neuron activity is stronger than that after hyperpolarizing current injection but is comparable with that resulting from stimulation of another inhibitory pathway (Fig. 10). The enhanced PY neuron activity is comparable with that resulting from either direct current injection or synaptic inhibition from another pathway (Fig. 10). 7. MCN5 activity increases the pyloric cycle frequency of both slow ( 1 Hz) and fast (1-2 Hz) rhythms (Fig. 11), and it significantly alters the phase relationships that define this motor pattern (Fig. 12). These phase relationships change again after MCN5 stimulation (Fig. 12). 8. MCN5 acts in concert with the pyloric pacemaker ensemble to elicit a pyloric rhythm that exhibits enhanced pacemaker neuron activity and reduced activity in all nonpacemaker neurons. Additionally, despite their electrical coupling, the three types of pacemaker neurons exhibit distinct responses to MCN5 stimulation. This partially uncouples their normally coactive bursts. The resulting motor pattern is distinct from all previously characterized pyloric rhythms.J Neurophysiol 1996751 97-108 d ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=100986351 Nassel, D. R.0<6Tachykinin-related peptides in invertebrates: a reviewAnimal Cockroaches/chemistry Crustacea/chemistry Horseshoe Crabs/chemistry Invertebrates/*chemistry Mollusca/chemistry Neuropeptides/*analysis/isolation & purification/metabolism Substance P/analysis Tachykinins/*analysis/isolation & purification/metabolism 6 0Peptides with sequence similarities to members of the tachykinin family have been identified in a number of invertebrates belonging to the mollusca, echiuridea, insecta and crustacea. These peptides have been designated tachykinin-related peptides (TRPs) and are characterized by the preserved C-terminal pentapeptide FX1GX2Ramide (X1 and X2 are variable residues). All invertebrate TRPs are myostimulatory on insect hindgut muscle, but also have a variety of additional actions: they can induce contractions in cockroach foregut and oviduct and in moth heart muscle, trigger a motor rhythm in the crab stomatogastric ganglion, depolarize or hyperpolarize identified interneurons of locust and the snail Helix and induce release of adipokinetic hormone from the locust corpora cardiaca. Two putative TRP receptors have been cloned from Drosophila; both are G-protein coupled and expressed in the nervous system. The invertebrate TRPs are distributed in interneurons of the CNS of Limulus, crustaceans and insects. In the latter two groups TRPs are also present in the stomatogastric nervous system and in insects endocrine cells of the midgut display TRP-immunoreactivity. In arthropods the distribution of TRPs in neuronal processes of the brain displays similar patterns. Also in coelenterates, flatworms and molluscs TRPs have been demonstrated in neurons. The activity of different TRPs has been explored in several assays and it appears that an amidated C-terminal hexapeptide (or longer) is required for bioactivity. In many invertebrate assays the first generation substance P antagonist spantide I is a potent antagonist of invertebrate TRPs and substance P. Locustatachykinins stimulate adenylate cyclase in locust interneurons and glandular cells of the corpora cardiaca, but in other tissues the putative second messenger systems have not yet been identified. The heterologously expressed Drosophila TRP receptors coupled to the phospholipase C pathway and could induce elevations of inositol triphosphate. The structures, distributions and actions of TRPs in various invertebrates are compared and it is concluded that the TRPs are multifunctional peptides with targets both in the central and peripheral nervous system and other tissues, similar to vertebrate tachykinins. Invertebrate TRPs may also be involved in developmental processes.'PJDepartment of Zoology, Stockholm University, Sweden. dnassel@zoologi.su.se10098635 1999Peptides201 141-58 Using Smart Source ParsingBPresynaptic control of neurones in pattern-generating networks\VAnimal Crayfish/physiology Ganglia/physiology Ganglia, Invertebrate/physiology Human Motor Activity/physiology *Neural Networks (Computer) Presynaptic Terminals/*physiology Psychomotor Performance/physiology Somatosensory Cortex/physiology Stomach/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Recent studies have revealed presynaptic influences on neurones that participate in rhythmic motor patterns. Although there is still little direct information about the effects of these inputs at presynaptic terminals, their functional consequences are being unraveled. These presynaptic influences gate sensory input to pattern-generating networks and locally alter the synaptic strength and/or the activity pattern of network neurones.hCurr Opin Neurobiol 199446 909-14>8Nusbaum, M.P. El Manira, A. Gossard, J.-P. Rosingnol, S. 1997VPPresynaptic mechanisms during rhythmic activity in vertebrates and invertebrates >8Stein, P.S.G. Grillner, S. Selverston, A.I. Stuart, D.G.*#Neuron, Networks and Motor Behavior  Cambridge, MA  MIT Press237-253V4ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11182454nD>Nusbaum, M. P. Blitz, D. M. Swensen, A. M. Wood, D. Marder, E.@9The roles of co-transmission in neural network modulation  Animal Crustacea/physiology Digestive System/innervation Ganglia, Invertebrate/*physiology Models, Neurological Nerve Net/*physiology Neurons/*physiology Neurotransmitters/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synaptic Transmission/*physiologyUNeuromodulation provides considerable flexibility to the output of neural networks. In spite of the extensive literature documenting the presence of modulatory peptide co-transmitters in many neurons, considerably less is known about the specific roles of co-transmission in circuit function. This review describes some of the potential consequences of peptide co-transmission in functional circuits, using specific examples from recent work on the actions of identified peptidergic projection neurons acting on the multifunctional neural network within the crustacean stomatogastric ganglion. This system reveals that co-transmission provides projection neurons with a rich assortment of strategies for eliciting multiple outputs from a multifunctional network.'Dept of Neuroscience, University of Pennsylvania School of Medicine, 215 Stemmler Hall, Philadelphia, PA 19104, USA. nusbaum@mail.upenn.edu11182454Trends Neurosci 2001243146-54.12563170606p 2002NHRegulating peptidergic modulation of rhythmically active neural circuits 378-87The ability of neuropeptides to modulate neural circuit activity is well established, but little is known regarding how the actions of neurally-released peptides are regulated. This issue is being studied in the isolated stomatogastric nervous system (STNS) of decapod crustaceans. The STNS is a small neural system that contains the rhythmically active gastric mill (chewing) and pyloric (filtering of chewed food) motor circuits within the stomatogastric ganglion (STG). These circuits are influenced by a set of modulatory projection neurons in the neighboring commissural and oesophageal ganglia. This system includes three different projection neurons that contain the peptide transmitter proctolin among an overlapping complement of cotransmitters. Despite their shared proctolinergic phenotype, when these projection neurons are activated individually each of them has distinct actions on the gastric mill and pyloric circuits. These distinct actions result only partly from the presence of different cotransmitters in these projection neurons. Also contributing to these distinct actions are differences in the pattern of transmitter release as well as a differential, peptidase-mediated sculpting of the actions of the proctolin released from each projection neuron. There is also a convergence of peptide cotransmitter actions, at the level of the target ion channel, which might limit the effectiveness of each individual cotransmitter. One lesson already learned from this small neural system is that there is a diverse collection of regulatory mechanisms for controlling the actions of neurally-released peptides on rhythmically active neural circuits.g'jcDepartment of Neuroscience, University of Pennsylvania, School of Medicine, Philadelphia, Pa., USA.CNusbaum, M. P.("22450251 0006-8977 Journal ArticleBrain Behav Evollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12563170,ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=120156152& Nusbaum, M. P. Beenhakker, M. P.:4A small-systems approach to motor pattern generationTNHow neuronal networks enable animals, humans included, to make coordinated movements is a continuing goal of neuroscience research. The stomatogastric nervous system of decapod crustaceans, which contains a set of distinct but interacting motor circuits, has contributed significantly to the general principles guiding our present understanding of how rhythmic motor circuits operate at the cellular level. This results from a detailed documentation of the circuit dynamics underlying motor pattern generation in this system as well as its modulation by individual transmitters and neurons.12015615 Nature 2002 417 6886343-50.9:3O'Neil, M. B. Abbott, L. F. Sharp, A. A. Marder, E.. 1995,&Dynamic clamp: computer-neural hybrids  Arbib, M.A.2,Handbook of Brain Theory and Neural Networks  Cambridge`  MIT Press`326-329XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=2568390.(Orchard, I. Belanger, J. H. Lange, A. B.2,Proctolin: a review with emphasis on insectsAnimal Insects/*metabolism/physiology Muscles/drug effects/*innervation Neurons/*metabolism/physiology Neurotransmitters/metabolism/*physiology Oligopeptides/metabolism/*physiologyThe distribution, physiological role, mode of action, and pharmacology of the pentapeptide neuroregulator proctolin are reviewed, with special emphasis on insects. Whereas proctolin is distributed extensively throughout arthropods, its presence in molluscs, annelids, or chordates is not well established. In the arthropods, proctolin acts as a neuromodulator and possibly as a neurohormone. It does not appear to function as a conventional neurotransmitter. Two model proctolinergic systems are highlighted: motor control of the visceral muscles of the locust oviduct and of the skeletal muscles of the locust ovipositor. In these preparations proctolin is a cotransmitter acting to enhance neuromuscular transmission and muscular contraction. The mode of action of proctolin is not well understood, although the second messengers cAMP, phosphatidyl inositol, and calcium have been implicated in various systems. Pharmacologically, the proctolin receptor has been examined with structure/activity studies, and the effects of a variety of amino acid substitutions and deletions of the pentapeptide are described. It is unfortunate that no specific antagonists of the proctolin receptor appear to be available and that no receptor-binding studies have been reported. The prospects are good for advances in our understanding of modulatory mechanisms, since proctolin appears to be emerging as the model for studies of this type.'D>Department of Zoology, University of Toronto, Ontario, Canada.2568390i J Neurobioli 1989205p470-96.r ~H* r @93353235D=Panchin, Y. V. Arshavsky, Y. I. Selverston, A. Cleland, T. A.rRKLobster stomatogastric neurons in primary culture. I. Basic characteristicspAction Potentials/drug effects Animal Axons/drug effects Cells, Cultured Dopamine/pharmacology Electrophysiology Ganglia/cytology Lobsters/*physiology Membrane Potentials/drug effects Neural Pathways/drug effects Neurites/drug effects Neurons/drug effects/*physiology Neurotransmitters/pharmacology Pilocarpine/pharmacology Stomach/*innervation Subtilisins/pharmacology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.r 1. A method for the isolation of stomatogastric neurons with neuropilar processes and an axon or = 7-10 days in a simple medium (salt-adjusted Leibovitz-15). Neurite outgrowth started immediately after plating and was maximal during the first 2-3 days. The electrical activity of neurons and their responses to bath application of pilocarpine were studied between 2 and 10 days after plating. 2. Identified neurons [pyloric dilator (PD), pyloric (PY), and lateral pyloric (LP) neurons from the pyloric pattern generator as well as gastric mill (GM) and lateral posterior gastric (LPG) neurons from the gastric mill pattern generator], isolated with neuropilar processes and axons, behaved in general like corresponding neurons in the isolated stomatogastric ganglion (STG). PD neurons were tonically active or silent in culture; pilocarpine caused them to begin rhythmic activity, which at particular levels of imposed polarization was similar to the pyloric rhythm in vitro. PY and LP neurons were silent. Pilocarpine produced some rhythmicity in the PY neuron, whereas in LP neurons it decreased the firing threshold to depolarizing current and accentuated postinhibitory rebound. LPG neurons were tonically active. Pilocarpine depolarized the LPG neurons and accelerated their tonic activity; neuron hyperpolarization by current injection led to bursting pacemaker activity that was similar to the gastric rhythm in vitro. GM neurons were silent; pilocarpine did not cause them to generate rhythmic activity but did lower their thresholds to depolarizing current. Simultaneous recordings from the soma and axon under direct visual control demonstrated that the intrasomatic spikes (15-20 mV in amplitude) were attenuated action potentials generated in the axon. 3. Neurons isolated with short primary neurites, including those without any noticeable primary neurite (in contrast to neurons isolated with longer neuropilar processes and axons), never generated any kind of electrical activity immediately after extraction from the STG. After 2 days in culture, these "short-neurite" neurons became capable of generating different types of electrical activity (e.g., fast spikes with amplitudes of or = 40-45 mV, plateau potentials, bursting potentials, etc.). The capability of isolated somata to generate electrical activity did not depend on whether or not the cell had adhered to the substrate and demonstrated neurite outgrowth.(ABSTRACT TRUNCATED AT 400 WORDS)J Neurophysiol 19936961976-92 Parker, T.J. 1976,&On the stomach of fresh-water crayfishJ Anat Physiol11 54-60Patwardhan, S.S. 1934On the structure and mechanism of the gastric mill in Decapoda. I. The structure of the gastric mill in Paratelphusa guerini (M. Edw.)ri}Proc Indian Acad Sci B1183-196Patwardhan, S.S. 1935{On the structure and mechanism of the gastric mill in Decapoda. II. A comparative account of the gastric mill in BrachyuraProc Indian Acad Sci B1359-375Patwardhan, S.S. 1935tnOn the structure and mechanism of the gastric mill in Decapoda. III. Structure of the gastric mill in AnomuraProc Indian Acad Sci B1405-413Patwardhan, S.S. 1935|On the structure and mechanism of the gastric mill in Decapoda. IV. The structure of the gastric mill in Reptantous MacruraProc Indian Acad Sci B1414-422Patwardhan, S.S. 1935On the structure and mechanism of the gastric mill in Decapoda. V. The structure of the gastric mill in Natantous Macrura - CaridaProc Indian Acad Sci B11693-704Patwardhan, S.S. 1935On the structure and mechanism of the gastric mill in Decapoda. VI. The structure of the gastric mill in Natantous Macrura - Panaediea and StenopideaProc Indian Acad Sci B1e155-174}"Pearson, K.G. Ramirez, J.-M. 1992D>Parallels with other invertabrate and vertebrate motor systems BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MAu  MIT Pressh263-282SB8Animal Cell Membrane/enzymology Crabs Cyclic GMP/*metabolism Cytosol/enzymology Digestive System/*innervation Ganglia, Invertebrate/*metabolism Guanylate Cyclase/metabolism Male Neurotransmitters/*physiology Nitric Oxide/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tissue DistributionIn the neural circuits that comprise the crustacean stomatogastric nervous system (STNS), synaptically delivered neurotransmitters and circulating neurohormones elicit a wide range of rhythmic motor outputs. However, functional roles for second messengers in this system are poorly understood. Here we demonstrate two different signaling pathways that control the synthesis of 3',5'-cGMP in the crab STNS. One pathway is activated by nitric oxide (NO) and is mediated by a cytoplasmic guanylate cyclase. A second pathway is stimulated by peptide-containing extracts from a crab neurohemal organ that activate a membrane-associated guanylate cyclase. Using whole-mount immunocytochemistry to localize individual cGMP-containing cells, we find that NO elevates intracellular cGMP in a small subset of STNS neurons. Immunopositive cells are found predominantly in the stomatogastric ganglion, with a few additional cells located in the oesophageal and commissural ganglia. Crab tissues differ in their sensitivities to NO and to the peptide-containing extract. The NO- mediated pathway is apparently restricted to the nervous system, whereas the peptidemediated pathway is present in every tissue tested. The results of these experiments demonstrate that multiple signaling pathways involving cGMP are present in the STNS and suggest that this second messenger may help control the metabolic and physiological status of these motor circuits. J Neurosci 1996165h1614-22o ,lyCrabs/chemistry/*genetics Crabs/genetics/*metabolism,&Crabs/growth & development/*metabolismCrabs/metabolism Crayfish Crayfish/*anatomy & histology,(Crayfish/*anatomy & histology/metabolismCrayfish/*chemistryCrayfish/*metabolismCrayfish/*physiology Crayfish/growth & developmentCrayfish/physiologyCross Reactions Crustacea($Crustacea Nervous system Congresses.Crustacea/*metabolismCrustacea/*physiologyCrustacea/chemistry Crustacea/cytology/physiologyCrustacea/physiology Culture MediaCurare/pharmacology CyberneticsCyclic AMP/*physiologyCyclic GMP/*metabolismCyclic GMP/*physiology4/Cycloleucine/analogs & derivatives/pharmacologyCytosol/enzymologyDactinomycin/pharmacology($Decamethonium Compounds/pharmacologyDecerebrate StateDendrites/*physiologyDendrites/metabolismDendrites/physiologyDendrites/ultrastructure Denervation Dentitiondevelopment/*physiologyDifferential ThresholdDigestive Physiology Digestive System/*innervation,&Digestive System/chemistry/innervationDigestive System/cytology40Digestive System/cytology/embryology/innervation84Digestive System/drug effects/innervation/physiology,'Digestive System/embryology/innervation Digestive System/innervation,(Digestive System/innervation/*physiology,'Digestive System/innervation/metabolism,'Digestive System/innervation/physiology DNA, Complementary/analysis Dopamine/*analysis/immunology Dopamine/*analysis/metabolismDopamine/*pharmacologyDopamine/*physiology<7Dopamine/administration & dosage/*metabolism/physiology$Dopamine/immunology/*metabolismDopamine/pharmacology$!Dopamine/pharmacology/*physiology$ Dopamine/pharmacology/physiologyDopamine/physiology$ Dose-Response Relationship, Drug85Drosophila melanogaster/*embryology/genetics/growth &Drosophila/geneticsDrug ResistanceDrug SynergismDyes Dyes/toxicityEating/*physiologyEdrophonium/pharmacology41Efferent Pathways/cytology/embryology/*metabolism Efferent Pathways/physiology0-Egtazic Acid/analogs & derivatives/metabolism4/Egtazic Acid/analogs & derivatives/pharmacologyEgtazic Acid/pharmacologyElectric Conductivity("Electric Conductivity/drug effectsElectric Stimulation($Electric Stimulation/instrumentationElectric WiringElectrical coupling ElectricityElectrochemistryElectromyographyElectrophysiologyElectroretinography EmbryoHCEmbryo, Nonmammalian/*embryology/*innervation/metabolism/physiology$Embryo, Nonmammalian/chemistry$Embryo, Nonmammalian/physiologyEmbryo/physiologyEnglish Abstract("Enteric Nervous System/*physiology$Enzyme Inhibitors/pharmacology<9Esophagus/anatomy & histology/*innervation/ultrastructureEsophagus/innervationEvoked Potentials$Evoked Potentials/drug effects,)Evoked Potentials/drug effects/physiology Evoked Potentials/physiology EvolutionEvolution, Molecular0+Excitatory Amino Acid Agonists/pharmacology4.Excitatory Amino Acid Antagonists/pharmacology4.Excitatory Postsynaptic Potentials/*physiology@:Excitatory Postsynaptic Potentials/drug effects/physiology0-Excitatory Postsynaptic Potentials/physiology$Extracellular Space/*physiology$Extracellular Space/metabolism4/Eye/anatomy & histology/innervation/*physiology$Eye/innervation/ultrastructure FeedbackFeedback/physiology Feeding Behavior/*physiology,)Feeding Behavior/drug effects/*physiology Feeding Behavior/physiology Female$Fluorescent Antibody Technique,(Fluorescent Antibody Technique, IndirectFluorescent Dyes$Fluorescent Dyes/diagnostic use D hPaupardin-Tritsch, D.Pearson, K. G. Pearson, K.G. Peck, J. Peck, J. H. Peck, J.H. Penzlin, H.Perez-Acevedo, N. L. Perkel, D. H. Pfluger, H.Pfluger, H. J.Pfluger, H.-J. Pinkser, H. Pinto, R. D. Poggio, T.A. Powell, R.R. Powers, L.S. Prinz, A. A. Proske, U. Pulver, S. R. Quigley, B.D.Quinlan, J. E. Quinones, L.Rabinovich, M.Rabinovich, M. I.Ramirez, J.-M. Raper, J. A. Raper, J.A.Rattananont, P. Reddy, A.R. Reglodi, D. Rehder, V. Reichert, H. Reina, C.Renaud-LeMasson, S. Rezer, E.Richards, K. S. Richter, D.W. Ritt, J.Roberts, P. D.Robertson, R. M.Robertson, R.M. Robie, A. A.Rodriguez, H.E. Romo, R. Rosingnol, S. Ross, W. N. Ross, W.N. Rossignol, S.Rothman, B. S. Rowat, P. Rowat, P. F. Rowat, P.F. Royer, S.M. Rudomin, P. Ruiz, M.Russell, D. F. Russell, D.F. Sallee, A. Samoilova, M.Sanchez-Andres, J. V. Schaefer, N. Scheer, B.T. Schlessinger Schmidt, M. Schmitt, F.O. Schmitz, E.H. Schneider, H. Scholtz, G. Scholz, N. L. Schulz, D. J. Segev, I.Sellereit, K. L.Selverston, A.Selverston, A. I.Selverston, A.I.Selverston, Allen I. Sen, K. Sharman, A. Sharp, A. A. Sharp, A.A. Si-Liang, Y. Siegel, M. Sigvardt, K.Sigvardt, K. A.Sillison, J.H.M. Simmers, A.J. Simmers, J. Simon, D. J. Sirchia, C.D.Siwicki, K. K.Skarbinski, J. Skiebe, P.Skilleter, G.A.Skinner, F. K. Sosa, M. A. Soto, C.Soto-Trevino, C. Spirito, C.P. Spruston, N. Stein, P.S.G. Stein, W. Stenger, D.A.Stewart, R. A. Storch, V. Storm, E. E.Strassburg, H. P. Stuart, D.G. Suh, H.-L.Sullivan, R. E. Suthers, I.M.Sweedler, J. V.Swensen, A. M. Szelier, M. Szucs, A. Szuts, Z. B. Takemoto, T. Tanner, S. L. Tautz, J.Taveras, J. M. Tazaki, K. Tazaki, Y. Terio, K. Tesauro, G.Thirumalai, V. Thistle, A.B.Thoby-Brisson, M.Thompson, R.S.Thoroughman, K. A. Thuma, J. B.Tierney, A. J. Todt, D. Torres, J. J.Touretsky, D.S. Touretzky, D. Tresch, M. C. Truman, J. W. Tsien, R.Y. Tsung, F.-S.Turrigiano, G.Turrigiano, G. G.Turrigiano, G.G.Van Weel, P.B.Van Wormhoudt, A. Varona, P. Vedel, J. Vedel, J. P. Vedel, J.-P. Vincent, P.Volkovskii, A. R. Wadepuhl, M. Wagner, R. Wales, W. Walton, K.D. Warner, G.F.Warshaw, H. S. Watling, L. Weaver, A. L. Webb, W. W. Weckwerth, W. Weigeldt, D.Weimann, J. M. Weimann, J.M. Weise, K. Wiese, K.Wilensky, A. E. Williams, L. Willis, W. Willms, A. Willms, A.R. Winlow, B.Withers, M. D.Wollenschlager, T. Wood, D. Wood, D. E.Wootton, J. F. Worden, F.G. Wu, J. Y. Xu, P. Yang, S.L. Yaple, R. Yarotsky, J. Yonge, C.M. Zarrin, A.R. Zhang, B. Zhang, Y.Zilberstein, Y. Zipfel, W. R. Zirpel, L.Nn Potentials Animal BiomechanicsDifferential ThresholdElectrophysiologyInterneurons/*physiologyLobsters/*physiologyD.JDStud Simmers, A.J. 1987JDAppendix A: Cellular integration in a gastric proprioceptive pathway "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlage242-251azPfluger, H. J.<5Neuromodulation during motor development and behavior,nhAging/*physiology Animal Behavior, Animal/*physiology Movement/*physiology Neurotransmitters/*physiologyImportant recent advances have been made in understanding the role of aminergic modulation during the maturation of Xenopus larvae swimming rhythms, including effects on particular ion channel types of component neurons, and the role of peptidergic modulation during development of adult central patterns generators in the stomatogastric ganglion of crustaceans. By recording from octopaminergic neuromodulatory neurons during ongoing motor behavior in the locust, new insights into the role of this peripheral neuromodulatory mechanism have been gained. In particular, it is now clear that the octopaminergic neuromodulatory system is automatically activated in parallel to the motor systems, and that both excitation and inhibition play important functional roles.'|Freie Universitat Berlin, Institut fur Biologie/Neurobiologie, Berlin, D-14195, Germany. pflueger@neurobiologie.fu-berlin.de10607635{http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10607635 http://www.biomednet.com/article/nb9602Curr Opin Neurobiol 199996 683-9.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11088744\VPinto, R. D. Varona, P. Volkovskii, A. R. Szucs, A. Abarbanel, H. D. Rabinovich, M. I.<6Synchronous behavior of two coupled electronic neuronsAnimal *Biological Clocks Computer Simulation Electrophysiology Ganglia, Invertebrate/cytology Lobsters/*physiology Membrane Potentials Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Synapses/physiologyWe report on experimental studies of synchronization phenomena in a pair of analog electronic neurons (ENs). The ENs were designed to reproduce the observed membrane voltage oscillations of isolated biological neurons from the stomatogastric ganglion of the California spiny lobster Panulirus interruptus. The ENs are simple analog circuits which integrate four-dimensional differential equations representing fast and slow subcellular mechanisms that produce the characteristic regular/chaotic spiking-bursting behavior of these cells. In this paper we study their dynamical behavior as we couple them in the same configurations as we have done for their counterpart biological neurons. The interconnections we use for these neural oscillators are both direct electrical connections and excitatory and inhibitory chemical connections: each realized by analog circuitry and suggested by biological examples. We provide here quantitative evidence that the ENs and the biological neurons behave similarly when coupled in the same manner. They each display well defined bifurcations in their mutual synchronization and regularization. We report briefly on an experiment on coupled biological neurons and four-dimensional ENs, which provides further ground for testing the validity of our numerical and electronic models of individual neural behavior. Our experiments as a whole present interesting new examples of regularization and synchronization in coupled nonlinear oscillators.'rkInstitute for Nonlinear Science, University of California, San Diego, La Jolla, California 92093-0402, USA.11088744B2 sites is desirable when studying neural circuits with serial or ring connectivity. Here, we describe how to extend dynamic clamp control to four neurons and their associated synaptic interactions, using a single IBM-compatible PC, an ADC/DAC interface with two analog outputs, and an additional demultiplexing circuit. A specific C++ program, DYNCLAMP4, implements these procedures in a Windows environment, allowing one to change parameters while the dynamic clamp is running. Computational efficiency is increased by varying the duration of the input-output cycle. The program simulates < or =8 Hodgkin-Huxley-type conductances and < or =18 (chemical and/or electrical) synapses in < or =4 neurons and runs at a minimum update rate of 5 kHz on a 450 MHz CPU. (Increased speed is possible in a two-neuron version that does not need auxiliary circuitry). Using identified neurons of the crustacean stomatogastric ganglion, we illustrate on-line parameter modification and the construction of three-member synaptic rings.t'Institute for Nonlinear Science, University of California, San Diego, 9500 Gilman Dr. #0402, La Jolla, CA 92093-0402, USA. reynaldo@ucsd.edu11459616J Neurosci Methods 2001 108v1t 39-48. Powell, R.R. 1974|The functional morphology of the foreguts of the thalassinid crustaceans Callianassa californiensis and Upogebia pugettensisIchUniv Cal Publ Zool 102n 1-41 Powers, L.S. 1973*$Gastric mill rhythms in intact crabsComp Biochem Physiol 46An767-783|> 12574423233 2003 Feb 1tmThe functional consequences of changes in the strength and duration of synaptic inputs to oscillatory neurons 943-54zsWe studied the effect of synaptic inputs of different amplitude and duration on neural oscillators by simulating synaptic conductance pulses in a bursting conductance-based pacemaker model and by injecting artificial synaptic conductance pulses into pyloric pacemaker neurons of the lobster stomatogastric ganglion using the dynamic clamp. In the model and the biological neuron, the change in burst period caused by inhibitory and excitatory inputs of increasing strength saturated, such that synaptic inputs above a certain strength all had the same effect on the firing pattern of the oscillatory neuron. In contrast, increasing the duration of the synaptic conductance pulses always led to changes in the burst period, indicating that neural oscillators are sensitive to changes in the duration of synaptic input but are not sensitive to changes in the strength of synaptic inputs above a certain conductance. This saturation of the response to progressively stronger synaptic inputs occurs not only in bursting neurons but also in tonically spiking neurons. We identified inward currents at hyperpolarized potentials as the cause of the saturation in the model neuron. Our findings imply that activity-dependent or modulator-induced changes in synaptic strength are not necessarily accompanied by changes in the functional impact of a synapse on the timing of postsynaptic spikes or bursts.a'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.i,&Prinz, A. A. Thirumalai, V. Marder, E.("22462250 1529-2401 Journal Article J NeurosciAction Potentials/physiology Animal Biological Clocks/*physiology Computer Simulation Electric Stimulation Ganglia, Invertebrate/cytology/physiology In Vitro *Models, Neurological Nephropidae Neural Conduction/physiology Neural Inhibition/physiology Neurons/*physiology Patch-Clamp Techniques Reaction Time/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synapses/*physiology Synaptic Transmission/physiologyclehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12574423/15558066712 2004 Decn@:Similar network activity from disparate circuit parameters1345-52LngIt is often assumed that cellular and synaptic properties need to be regulated to specific values to allow a neuronal network to function properly. To determine how tightly neuronal properties and synaptic strengths need to be tuned to produce a given network output, we simulated more than 20 million versions of a three-cell model of the pyloric network of the crustacean stomatogastric ganglion using different combinations of synapse strengths and neuron properties. We found that virtually indistinguishable network activity can arise from widely disparate sets of underlying mechanisms, suggesting that there could be considerable animal-to-animal variability in many of the parameters that control network activity, and that many different combinations of synaptic strengths and intrinsic membrane properties can be consistent with appropriate network performance.'Volen Center and Biology Department, Brandeis University, Mail Stop 013, 415 South Street, Waltham, Massachusetts 02454-9110, USA.("Prinz, A. A. Bucher, D. Marder, E. 1097-6256 Journal Article Nat Neuroscilehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1555806612209843 4511 2002 Sep 9haNeuromodulatory complement of the pericardial organs in the embryonic lobster, Homarus americanus 79-90]TMThe pericardial organs (POs) are a pair of neurosecretory organs that surround the crustacean heart and release neuromodulators into the hemolymph. In adult crustaceans, the POs are known to contain a wide array of peptide and amine modulators. However, little is known about the modulatory content of POs early in development. We characterize the morphology and modulatory content of pericardial organs in the embryonic lobster, Homarus americanus. The POs are well developed by midway through embryonic (E50) life and contain a wide array of neuromodulatory substances. Immunoreactivities to orcokinin, extended FLRFamide peptides, tyrosine hydroxylase, proctolin, allatostatin, serotonin, Cancer borealis tachykinin-related peptide, cholecystokinin, and crustacean cardioactive peptide are present in the POs by approximately midway through embryonic life. There are two classes of projection patterns to the POs. Immunoreactivities to orcokinin, extended FLRFamide peptides, and tyrosine hydroxylase project solely from the subesophageal ganglion (SEG), whereas the remaining modulators project from the SEG as well as from the thoracic ganglia. Double-labeling experiments with a subset of modulators did not reveal any colocalized peptides in the POs. These results suggest that the POs could be a major source of neuromodulators early in development.o'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA. Pulver, S. R. Marder, E.("22198808 0021-9967 Journal Article J Comp NeurolmNGAnimal Heart/embryology/innervation Lobsters/chemistry/*embryology Nervous System/chemistry/cytology/embryology Neural Pathways Neuropeptides/*analysis Neurosecretory Systems/*chemistry/embryology Neurotransmitters/analysis Oligopeptides/analysis Serotonin/analysis Support, U.S. Gov't, P.H.S. Tyrosine 3-Monooxygenase/analysisJlehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12209843a<79203252 Raper, J. A.`YNonimpulse-mediated synaptic transmission during the generation of a cyclic motor programuAnimal Lobsters Membrane Potentials Motor Neurons/physiology Support, U.S. Gov't, P.H.S. Synapses/*physiology *Synaptic Transmission/drug effects Tetrodotoxin/pharmacologyhA small neuronal network in the lobster stomatogastric ganglion, composed of impulse-producing motor neurons, gives rise to cyclic patterned outputs. This network continues to generate its cyclic motor program if impulse production within the ganglion is blocked. Continuously graded, nonimpulse-mediated, chemical synaptic transmission is suffucient to coordinate neuronal activity in a functioning pattern generator.Science 1979 205 4403 304-6 Reddy, A.R. 1935The structure, mechanism and development of the gastric armature in Stomatopoda with a discussion as to its evolution in decapodaProc Indian Acad Sci B1h650-675hZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10465508 6/Reglodi, D. Lubics, A. Szelier, M. Lengvari, I.ub[Gastrin- and cholecystokinin-like immunoreactivities in the nervous system of the earthwormr Animal Cholecystokinin/*isolation & purification Ganglia, Invertebrate/chemistry Gastrins/*isolation & purification Immunohistochemistry Nervous System/*chemistry Oligochaeta/*chemistry Peripheral Nervous System/chemistry Serotonin/*isolation & purification Support, Non-U.S. Gov't& The distribution of cholecystokinin and gastrin-like immunoreactive cell bodies and fibers in the nervous system of 2 annelid worms, Lumbricus terrestris and Eisenia fetida, has been studied by means of immunohistochemistry. The cerebral ganglion contains 170-250, the subesophageal ganglion contains 120-150, and the ventral ganglia contain 50-75 cholecystokinin immunoreactive cells, that represent 8- 12%, 8-10% and 4-5% of the total cell number, respectively. The anti- gastrin serum stained 330-360 nerve cells in the cerebral, 32-46 in the subesophageal and 7-25 in the ventral cord ganglia, representing 15- 16%, 2-3% and 0.5-2% of the total cell number. Immunopositivity was found with both antisera in the enteric nervous system, where the stomatogastric ganglia and the enteric plexus contain immunoreactive cells and fibers. Immunopositive cells were found in the epithelial and subepithelial cells, as well as in nerve cells innervating the muscular layer of the gastrointestinal tube. Various epidermal sensory cells also displayed strong immunoreactivity. According to our findings and the results of several functional studies, it is suggested that in annelids cholecystokinin- and gastrin-like peptides may be involved in digestive regulation, sensory processes and central integrating processes.'f`Department of Anatomy, University Medical School, Pecs, Hungary. dreglod@mailhost.tcs.tulane.edu10465508 1999Peptides205  569-77 Using Smart Source Parsing>8Renaud-LeMasson, S. LeMasson, G. Marder, E. Abbott, L.F. 1993JDHybrid circuits of interacting computer model and biological neurons *$Hanson, S.J. Cowan, J.D. Giles, C.L.81Advances in Neural Information Processing Systemsd  San Mateos Morgan Kaufmann Publishers5e813-819BRezer, E. Moulins, M.e 1980piModalites d'expression du generateur du rythme pylorique chez les crustaces: Analyses electromyographiqueC R Acad Sci Paris 291353-356/Rezer, E. Moulins, M 1983RKExpression of the crustacean pyloric pattern generator in the intact animalJ Comp Physiol 153 17-28 Rezer, E. 1987XRLes activites motrices rhythmiques de l'intestin anterieur des crustaces decapodes  Leger, C.L.0*La Nutrition des Crustaces et des Insectes Paris CNERNA 38-57f |156019442450 2004 Dec 15\UDifferent sensory systems share projection neurons but elicit distinct m12944532906 2003 DecrlAlternative to hand-tuning conductance-based models: construction and analysis of databases of model neurons 3998-4015|Conventionally, the parameters of neuronal models are hand-tuned using trial-and-error searches to produce a desired behavior. Here, we present an alternative approach. We have generated a database of about 1.7 million single-compartment model neurons by independently varying 8 maximal membrane conductances based on measurements from lobster stomatogastric neurons. We classified the spontaneous electrical activity of each model neuron and its responsiveness to inputs during runtime with an adaptive algorithm and saved a reduced version of each neuron's activity pattern. Our analysis of the distribution of different activity types (silent, spiking, bursting, irregular) in the 8-dimensional conductance space indicates that the coarse grid of conductance values we chose is sufficient to capture the salient features of the distribution. The database can be searched for different combinations of neuron properties such as activity type, spike or burst frequency, resting potential, frequency-current relation, and phase-response curve. We demonstrate how the database can be screened for models that reproduce the behavior of a specific biological neuron and show that the contents of the database can give insight into the way a neuron's membrane conductances determine its activity pattern and response properties. Similar databases can be constructed to explore parameter spaces in multicompartmental models or small networks, or to examine the effects of changes in the voltage dependence of currents. In all cases, database searches can provide insight into how neuronal and network properties depend on the values of the parameters in the models.'voVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454, USA. prinz@brandeis.edu0)Prinz, A. A. Billimoria, C. P. Marder, E. 0022-3077 Journal ArticleJ NeurophysiolAlgorithms Animals Computer Simulation *Databases, Factual Electric Stimulation Electrophysiology Membrane Potentials/physiology Models, Neurological Nephropidae Neurons/classification/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.lehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12944532 Axons/physiology94045853$Rowat, P. F. Selverston, A. I.ngModeling the gastric mill central pattern generator of the lobster with a relaxation-oscillator networkejdAnimal Computer Simulation Ganglia, Invertebrate/physiology Lobsters/*physiology Mastication/*physiology Membrane Potentials/physiology *Models, Neurological Models, Theoretical Nerve Net/*physiology Neural Inhibition/physiology Stomatognathic System/*innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synaptic Transmission/physiology 1. The gastric mill central pattern generator (CPG) controls the chewing movements of teeth in the gastric mill of the lobster. This CPG has been extensively studied, but the precise mechanism underlying pattern generation is not well understood. The goal of this research was to develop a simplified model that captures the principle, biologically significant features of this CPG. We introduce a simplified neuron model that embodies approximations of well-known membrane currents, and is able to reproduce several global characteristics of gastric mill neurons. A network built with these neurons, using graded synaptic transmission and having the synaptic connections of the biological circuit, is sufficient to explain much of the network's behavior. 2. The cell model is a generalization and extension of the Van der Pol relaxation oscillator equations. It is described by two differential equations, one for current conservation and one for slow current activation. The model has a fast current that may, by adjusting one parameter, have a region of negative resistance in its current-voltage (I-V) curve. It also has a slow current with a single gain parameter that can be regarded as the combination of slow inward and outward currents. 3. For suitable values of the fast current parameter and the slow current parameter, the isolated model neuron exhibits several different behaviors: plateau potentials, postinhibitory rebound, postburst hyperpolarization, and endogenous oscillations. When the slow current is separated into inward and outward fractions with separately adjustable gain parameters, the model neuron can fire tonically, be quiescent, or generate spontaneous voltage oscillations with varying amounts of depolarization or hyperpolarization. 4. The most common form of synaptic interaction in the gastric CPG is reciprocal inhibition. A pair of identical model cells, connected with reciprocal inhibition, oscillates in antiphase if either the isolated cells are endogenous oscillators, or they are quiescent without plateau potentials, or they have plateau potentials but the synaptic strengths are below a critical level. If the isolated cells have widely differing frequencies (or would have if the cells were made to oscillate by adjusting the fast currents), reciprocal inhibition entrains the cells to oscillate with the same frequency but with phases that are advanced or retarded relative to the phases seen when the cells have the same frequency. The frequency of the entrained pair of cells lies between the frequencies of the original cells. The relative phases can also be modified by using very unequal synaptic strengths.(ABSTRACT TRUNCATED AT 400 WORDS)J Neurophysiol 19937031030-53 Royer, S.M. 1987VOChronic effects of de-afferentation on the stomatogastric ganglion of Panulirus "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlago251-257h Russell, D.F. 1976HARhythmic excitatory inputs to the lobster stomatogastric ganglion Brain Res 101582-588 (92211270Rezer, E. Moulins, M. tmHumoral induction of pyloric rhythmic output in lobster stomatogastric ganglion: in vivo and in vitro studiesrAnimal Blood/physiology Blood Physiology Denervation Female Ganglia/*physiology Gastrointestinal System/innervation/physiology Lobsters/*physiology Male Muscle Contraction Muscles/innervation Neurons/*physiology Periodicity Support, Non-U.S. Gov'tIn the lobster Jasus lalandii, 14 neurones of the stomatogastric ganglion (STG) are organized in a network that produces rhythmic pyloric outputs. In vitro experiments have shown that the STG neurones receive, via the stomatogastric nerve (stn), neuromodulatory inputs that influence the expression of the bursting properties of the neurones and the ability of the network to produce its rhythmic output. In contrast to these in vitro observations, in vivo transection of the stn does not abolish the pyloric rhythm. Rhythmic output can be recorded by electromyography immediately after stn transection and for up to 2 years afterwards. We have shown that, under these experimental conditions, the STG appears to be isolated from any neuronal input that might account for the maintenance of the rhythmic output. Experiments carried out in the 2 days after stn transection showed that an in vitro preparation of the isolated STG was unable to produce any rhythmic output, but blood serum added to the system could restore the pyloric output. These results suggest strongly that the pyloric network receives neural and humoral modulatory influences in parallel and that each type of influence alone is able to maintain the bursting capability of the pyloric neurones.i J Exp Biol 1992 163s 209-30.(Richards, K. S. Miller, W. L. Marder, E.F?Maturation of lobster stomatogastric ganglion rhythmic activityL\VAnimal Digestive System/innervation Embryo, Nonmammalian/physiology Evoked Potentials Female Ganglia, Invertebrate/embryology/growth & development/*physiology In Vitro Larva Lobsters Muscle Fibers/physiology Muscles/innervation Neuromuscular Junction/*physiology Neurons/*physiology Oocytes Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.jdThe stomatogastric ganglion of the adult lobster, Homarus americanus generates extremely regular pyloric rhythms with a characteristic period of 0.5-1.5 Hz. To study the changes in the pyloric rhythm during embryonic and larval development, we recorded excitatory junctional potentials evoked by lateral pyloric (LP) neuron activity. Early in development the motor discharge of the LP neuron was often irregular, preventing use of conventional analysis methods that rely on extracting burst times to calculate cycle frequency and its variability. Instead, cycle frequency was determined for the LP neuron from the peak of the power spectrum obtained from the occurrence times of excitatory junctional potentials in the p1 muscle. The ratio of the power in the peak to the power from 0 to 3 Hz was used as a relative measure of the regularity of the rhythm. Throughout embryonic and the first larval stage, LP neuron activity is slow, irregular, and only weakly periodic. The regularity of the rhythm increased during midlarval stages, and both the frequency and regularity increased considerably by the postlarval stage LIV.'jdVolen Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02454-9110, USA.10515991http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10515991 http://www.jn.org/cgi/content/full/82/4/2006 http://www.jn.org/cgi/content/abstract/82/4/2006J Neurophysiol 19998242006-9.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10880130n Richards, K. S. Marder, E.tmThe actions of crustacean cardioactive peptide on adult and developing stomatogastric ganglion motor patterns^WAnimal Female Ganglia/*drug effects/embryology/physiology Larva/drug effects/physiology Lobsters/*drug effects/embryology/physiology Male Membrane Potentials/drug effects/physiology Motor Neurons/*drug effects/physiology Neuropeptides/*pharmacology/physiology Pylorus/drug effects/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.o,&The motor patterns produced by the stomatogastric ganglion (STG) are strongly influenced by descending modulatory inputs from anterior ganglia. With these inputs intact, in control saline, the motor patterns produced by the stomatogastric nervous system of embryonic and larval lobsters are slower and less regular than those of adult lobsters. We studied the effects of the hormonal modulator, crustacean cardioactive peptide (CCAP) on the discharge patterns of STG motor patterns in embryos, larvae, and adult Maine lobsters, Homarus americanus, with the anterior inputs present and absent. In adults, CCAP initiated robust pyloric rhythms from STGs isolated from their descending control and modulatory inputs. Likewise, CCAP initiated robust activity in isolated embryonic and larval STGs. Nonetheless, quantitative analyses revealed that the frequency and regularity of the STG motor neuron discharge seen in the presence of CCAP in isolated STGs from embryos were significantly lower than those seen late in larval life and in adults under the same conditions. In contrast, when the descending control and modulatory pathways to the STG were left intact, the embryonic and larval burst frequency seen in the presence of CCAP was increased by CCAP, whereas the burst frequency in adults was decreased by CCAP, so that in CCAP the frequencies at all stages were statistically indistinguishable. These data argue that immature embryonic motor patterns seen in the absence of CCAP are a function of immaturity in both the STG and in the descending and modulatory pathways.'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.10880130 J Neurobiol 2000441 31-44.HGFE ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10940943)<5Sharman, A. Hirji, R. Birmingham, J. T. Govind, C. K.urkCrab stomach pyloric muscles display not only excitatory but inhibitory and neuromodulatory nerve terminalsi:3Animal Crabs/*physiology Female Microscopy, Electron Movement/physiology Muscles/innervation Neural Inhibition/*physiology Neurons/*physiology/ultrastructure Neurotransmitters/physiology Presynaptic Terminals/*physiology/ultrastructure Stomach/innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.xMovements of the foregut in crustaceans are produced by striated muscles that are innervated by motor neurons in the stomatogastric ganglion (STG). Firing of the STG motor neurons generates excitatory junctional potentials (EJPs) in the stomach muscles. We now provide evidence for the existence of separate inhibitory and neuromodulatory innervations of some pyloric muscles in the foregut of several crabs, Callinectes sapidus, Cancer magister, and Cancer borealis. Electron microscopic examination of several pyloric muscles revealed three distinct types of nerve terminals. Excitatory terminals were readily identified by the spherical shape of their small, clear synaptic vesicles. These terminals also housed a few large dense core vesicles. Inhibitory nerve terminals were recognized by the elliptical shape of their small, clear synaptic vesicles, and contacted the muscles at well- defined synapses equipped with dense bar active zones. Bath application of GABA reduced the amplitudes of EJPs in a pyloric muscle of C. borealis, consistent with the presence of GABAergic inhibitory innervation. Neuromodulatory terminals were characterized by their predominant population of large dense and dense core vesicles. These terminals formed synapses with presynaptic dense bars on the muscle, as well as on the excitatory and inhibitory nerve terminals. The presence of the inhibitory and neuromodulatory terminals creates a functional context for previously described reports of neuromodulatory actions on stomach muscles and suggests that the transfer function from STG motor patterns to pyloric movement may be orchestrated by a complex innervation from sources outside of the STG itself.'hbLife Sciences Division, University of Toronto at Scarborough, Scarborough, Ontario M1C1A4, Canada.10940943 J Comp Neurol 2000 4251 70-81.92333386,%Sharp, A. A. Abbott, L. F. Marder, E.<6Artificial electrical synapses in oscillatory networksAnimal Cells, Cultured Electric Conductivity Electric Wiring GABA/pharmacology Nerve Net/*physiology Neural Inhibition Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/drug effects/*physiology 1. We use an electronic circuit to artificially electrically couple neurons. 2. Strengthening the coupling between an oscillating neuron and a hyperpolarized, passive neuron can either increase or decrease the frequency of the oscillator depending on the properties of the oscillator. 3. The result of electrically coupling two neuronal oscillators depends on the membrane potentials, intrinsic properties of the neurons, and the coupling strength. 4. The interplay between chemical inhibitory synapses and electrical synapses can be studied by creating both chemical and electrical synapses between two cultured neurons and by artificially strengthening the electrical synapse between the ventricular dilator and one pyloric dilator neuron of the stomatogastric ganglion.J Neurophysiol 1992676 1691-4:3Sharp, A. A. O'Neil, M. B. Abbott, L. F. Marder, E.u 1993F@The dynamic clamp: artificial conductances in biological neuronsTrends Neurosci41610 389-9494069767Animal *Computer Simulation Human *Models, Neurological *Neural Conduction Neural Pathways/physiology Neurons/*physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.>7The dynamic clamp is a novel method that uses computer simulation to introduce conductances into biological neurons. This method can be used to study the role of various conductances in shaping the activity of single neurons, or neurons within networks. The dynamic clamp can also be used to form circuits from previously unconnected neurons. This approach makes computer simulation an interactive experimental tool, and will be useful in many applications where the role of synaptic strengths and intrinsic properties in neuronal and network dynamics is of interest.93217517:3Sharp, A. A. O'Neil, M. B. Abbott, L. F. Marder, E.oD>Dynamic clamp: computer-generated conductances in real neuronsPJAnimal Axons/physiology Cells, Cultured *Computer Simulation Crabs Electric Stimulation/instrumentation Ganglia/physiology Membrane Potentials/physiology Microelectrodes *Models, Neurological Neural Conduction/*physiology *Neural Networks (Computer) Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/*physiology1. We describe a new method, the dynamic clamp, that uses a computer as an interactive tool to introduce simulated voltage and ligand mediated conductances into real neurons. 2. We simulate a gamma-aminobutyric acid (GABA) response of a cultured stomatogastric ganglion neuron to illustrate that the dynamic clamp effectively introduces a conductance into the target neuron. 3. To demonstrate an artificial voltage- dependent conductance, we simulate the action of a voltage-dependent proctolin response on a neuron in the intact stomatogastric ganglion. We show that shifts in the activation curve and the maximal conductance of the response produce different effects on the target neuron. 4. The dynamic clamp is used to construct reciprocal inhibitory synapses between two stomatogastric ganglion neurons that are not coupled naturally, illustrating that this method can be used to form new networks at will.J Neurophysiol 1993693 992-5F    &; + 3 OH_o  x  5U/~ E ]  h w'  q O2S _ ' /Auh   h  8  S )`I p w}    6 D ]T ) . 5  M S)9\lP { H     .   Y  IfGq$v, :    ,: " M^l 'w U[ & GL& 1G ?Wcl7Cx  12500313542e 2003 Feb 5ZTSerotonin in the developing stomatogastric system of the lobster, Homarus americanus 380-92We studied the development of the serotonergic modulation of the stomatogastric nervous system of the lobster, Homarus americanus. Although the stomatogastric ganglion (STG) is present early in embryonic development, serotonin immunoreactivity is not visible in the STG until the second larval stage. However, incubation of the STG with exogenous serotonin showed that a serotonin transporter is present in embryonic and early larval stages. Serotonin uptake was blocked by paroxetine and 0% Na(+) saline. The presence of a serotonin transporter in the embryonic STG suggests that hormonally liberated serotonin could be taken up by the STG, and potentially released as a "borrowed transmitter". Consistent with a potential hormonal role, serotonin is found in the pericardial organs, a major neurosecretory structure, by midembryonic development. The rhythmic motor patterns produced by embryonic and larval STGs were decreased in frequency by serotonin. Lateral Pyloric (LP) neuron-evoked excitatory junctional potentials (EJPs) in the embryos and the first larval stage (LI) were larger, slower, and more variable than those in the adult. The amplitude of adult LP neuron-evoked EJPs was increased more than twofold in serotonin, but in embryos and LI preparations this effect was negligible. In embryos and LI preparations, serotonin increased the occurrence of muscle fiber action potentials and altered the EJP wave-form. These data demonstrate that serotonin receptors are present in the stomatogastric nervous system early in development, and suggest that the role of serotonin changes from modulation of muscle fiber excitability early in development to enhancement of neurally evoked EJPs in the adult.'^WVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454.HBRichards, K. S. Simon, D. J. Pulver, S. R. Beltz, B. S. Marder, E.("22387772 0022-3034 Journal Article J Neurobiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=125003138735232724 1996 Jun:4The stomatogastric nervous system: a formal approach1089-105A discrete mathematical formalism (d-space) which is specifically designed to investigate discrete aspects of behavior is applied to the foregut of decapod crustacea. This approach differs from continuous modeling techniques in that the analysis determines a structure in which the observed behavior of the foregut is constrained. A notation for the implementation of the formalism is developed as well as a coordinate system natural to the functioning of the gastric mill. The formalism is used to organize previous observations that suggest potential courses of further experimental investigation. A detailed analysis of observed chewing modes of the gastric mill is presented, along with a discussion of the overall organization of the interrelationships between these modes. The investigation also addresses the relationship between behavioral modes of a pyloric muscle found in the shrimp Palaemon. Two alternative hypotheses are presented to describe the relationship of the behavioral components of the gastric mill: an interlaced control scheme in which the components are freely exchanged, and a top-down control system where the chewing modes are rigidly separated into packages. Flow through regions of state space in time is found to be important in determining the relations between the discrete behavioral components. The behavior of the foregut, like that of other motor control systems, is shown to fit naturally into the d-space formalism.'JCR. S. Dow Neurological Sciences Institute, Portland, OR 97209, USA.p"Roberts, P. D. McCollum, G.u 0306-4522 Journal Articlet NeuroscienceAnimals Behavior, Animal/physiology Crustacea/*physiology Ganglia, Invertebrate/physiology Intestines/innervation/physiology Logic Mastication/physiology *Models, Neurological Muscles/innervation/physiologyjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8735232XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9300421Roberts, P. D.HBClassification of rhythmic patterns in the stomatogastric ganglionAnimal Behavior, Animal/physiology Crustacea/*physiology Ganglia, Invertebrate/cytology/physiology *Models, Neurological Mouth/innervation Nerve Net/cytology/*physiology Neurons/*physiology Periodicity Stomach/innervation Support, U.S. Gov't, P.H.S.PnhA large class of neural pattern generators change their rhythmic output under the influence of neuromodulators. We present a method for identifying the variety of rhythmic patterns generated by small neural networks. The technique provides a tool for investigating the biological mechanisms responsible for pattern generation and pattern switching. Discrete methods based on transition graphs are applied to dynamic biological networks to generate sets of possible rhythmic behaviours. A measure is introduced onto the set of rhythms to quantify their differences and organize the set according to clusters of similar rhythms. Each cluster represents a different operational mode of the network. Examples are drawn from the stomatogastric ganglion, a well studied network that controls the muscles in the foregut of crustaceans. Classes of rhythms are found that correspond to experimentally observed patterns, and other classes of rhythms are found that have not yet been observed. Predictions are made for the rhythmic output of the stomatogastric ganglion under specific manipulations of parameters in the biological network.'HBR.S. Dow Neurological Sciences Institute, Portland, OR 97209, USA.9300421s Neuroscience 1997811m281-96.v80101687& Robertson, R. M. Laverack, M. S.tnOesophageal sensors and their modulatory influence on oesophageal peristalsis in the lobster, Homarus gammarusAnimal Electrophysiology Esophagus/anatomy & histology/*innervation/ultrastructure Lobsters/*physiology Peristalsis Receptors, Sensory/anatomy & histology/physiology The musculature and innervation of the oesophagus of Homarus gammarus are described as a prerequisite to studies on the mechanisms and control of food ingestion. Of particular interest are two paired sensors (the anterior and posterior oesophageal sensors) which are bilaterally situated at the oesophageal-cardiac sac valve. These are similar to contact chemoreceptors previously described in insects and are classified as such on morphological grounds and with indirect electrophysiological evidence. Oesophageal peristalsis is effected by the coordinated contraction of the Oesophageal musculature. This is controlled by rhythmical bursting neuronal activity, which can be recorded from the nerve trunks in the area. A characteristic burst recorded from the superior oesophageal nerve is used as an indication of oesophageal dilatation during peristalsis for studies on the feedback effects of the oesophageal sensors. Electrical and chemical stimulation of the posterior oesophageal sensors can initiate and increase the frequency of oesophageal peristalsis, while stimulation of the anterior oesophageal sensors can slow and terminate oesophageal peristalsis. The results are discussed and a model presented of the role of the oesophageal sensors in feeding.p Proc R Soc Lond B Biol Sci 1979 206u 1163 235-63p N  480101686& Robertson, R. M. Laverack, M. S.TMThe structure and function of the labrum in the lobster Homarus gammarus (L.)eAnimal Electrophysiology Lobsters/anatomy & histology/*physiology Mouth/*innervation Movement Receptors, Sensory/anatomy & histologyThe labrum of decapod crustaceans is a soft lobe overhanging the mouth. The labral skeleton, musculature and innervation of Homarus gammarus are described. There are three bilateral groups of sensory neurons innervating the floor, lobe and lateral walls of the labrum. These are probably responsible for the phasic afferent activity that can be recorded from the inner labral nerve on mechanical deformation of the labrum. The labrum undergoes rhythmical retraction-protraction movements during ingestion and is shown to be active during both mandibular activity and oesophageal peristalsis. Studies were made on the duration and frequency of labral "swallowing" activity. The role of the labrum in feeding is discussed. Proc R Soc Lond B Biol Sci 1979 206 1163 209-3382061833"Robertson, R. M. Moulins, M.\VFiring between two spike thresholds: implications for oscillating lobster interneuronsAnimal Axons/physiology Esophagus/innervation Ganglia/physiology Interneurons/*physiology Lobsters Membrane Potentials Support, Non-U.S. Gov'tAn identified interneuron in the lobster commissural ganglia fires spikes only between membrane potential values of -60 and -30 millivolts. The membrane potential of this neuron can also oscillate, and interaction between these two properties has important implications in determining the firing pattern of the neuron itself and the modalities of driving of a distant postsynaptic neuron.Science 1981 214 4523 941-382192143"Robertson, R. M. Moulins, M.{A corollary discharge of total foregut motor activity is monitored by a single interneurone in the lobster Homarus gammarusAnimal Digestive Physiology Digestive System/innervation/physiology Interneurons/physiology Lobsters/*physiology Membrane Potentials Peristalsis Support, Non-U.S. Gov't1. In Homarus, an identified interneurone (the L cell), which possesses the largest cell body in the commissural ganglion and projects to the brain, exhibits a complex firing pattern (Fig. 2 a). 2. It is shown that the L cell discharges with each of the 4 pattern generators of the stomatogastric nervous system which organize the rhythmic motor activity of the foregut (Fig. 2 b-e). 3. Manipulation of the membrane potential of the L cell does not induce any change in the 4 rhythms (Fig. 3), and it is concluded that the L cell is driven by the 4 pattern generators. 4. The functional meaning of this complex corollary discharge of the total foregut motor activity is discussed.J Physiol (Paris) 1981778 823-781149351"Robertson, R. M. Moulins, M.VOControl of rhythmic behaviour by a hierarchy of linked oscillators in crustaceatAnimal Crustacea/*physiology Feeding Behavior/*physiology Lobsters/physiology Pylorus/innervation/physiology Stomach/innervation/physiology Support, Non-U.S. Gov'tvIn Homarus, the central pattern generators for the rhythmic motor activities of the gastric teeth and the pyloric chamber are located in the stomatogastric ganglion. It is shown that independent gastric and pyloric oscillators are also contained in higher nervous centres (the commissural ganglia) and provide a phasic rhythmic input to the stomatogastric pattern generators. This demonstrates that rhythmic behaviour can be organized by a hierarchy of linked oscillators each capable of producing the rhythm. Neurosci Lett 1981211 111-6"Robertson, R.M. Moulins, M. 1981{Oscillatory command input to the motor pattern generators of the crustacean stomatogastric ganglion. I. The pyloric rhythmJ Comp Physiol 143i453-463c"Robertson, R.M. Moulins, M.t 1984|Oscillatory command input to the motor pattern generators of the crustacean stomatogastric ganglion. II. The gastric rhythmJ Comp Physiol 154i473-491c89160838Ross, W. N. Graubard, K.|vSpatially and temporally resolved calcium concentration changes in oscillating neurons of crab stomatogastric ganglionAction Potentials Algorithms Animal Arsenazo III Calcium/*physiology Crabs Ganglia/*physiology In Vitro Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.Calcium concentration changes during oscillations of the membrane potential of crab (Cancer irroratus or Cancer borealis) stomatogastric neurons were monitored at many positions by using the calcium indicator dye arsenazo III and a photodiode array. Data analysis algorithms using signal averaging techniques were developed to improve the time resolution of the measured calcium changes. As previously reported, calcium oscillations were detected from all regions of the neuropil but not from the soma or axon. In some cells step increases in intracellular neuropil calcium were correlated with each of the action potentials in the burst (on the peak of the voltage oscillation). In other cells we observed calcium oscillations phase-locked to the membrane potential with no spike-related component. A few cells had both spike-evoked and graded potential components to the calcium oscillations. In those cells, the spatial distribution of the spike- correlated calcium influx differed from that of the voltage-oscillation- correlated calcium influx, suggesting that different neurites might interact with their postsynaptic targets with different mixtures of graded and spike-correlated transmitter release. Proc Natl Acad Sci U S A 1989865c1679-83 "Rowat, P.F. Selverston, A.I. 1991\ULearning algorithms for oscillatory networks with gap junctions and membrane currentsNetwork2 17-41   :83058851$Russell, D. F. Hartline, D. K.rkSlow active potentials and bursting motor patterns in pyloric network of the lobster, Panulirus interruptusoAnimal Ganglia/*physiology In Vitro Lobsters/*physiology Membrane Potentials Models, Neurological Motor Neurons/physiology Periodicity Support, U.S. Gov't, P.H.S. Synapses/physiologyNH1. Neurons in the central pattern generator for the "pyloric" motor rhythm of the lobster stomatogastric ganglion were investigated for the possible involvement of regenerative membrane properties in their membrane-potential oscillations and bursting output patterns. 2. Evidence was found that each class of pyloric-system neurons can possess a capability for generating prolonged regenerative depolarizations by a voltage-dependent membrane mechanism. Such responses have been termed plateau potentials. 3. Several tests were applied to determine whether a given cell possessed a plateau capability. First among these was the ability to trigger all-or-none bursts of nerve impulses by brief depolarizing current pulses and to terminate bursts in an all-or-none fashion with brief hyperpolarizing current pulses. Tests were made under conditions of a high level of activity in the pyloric generator, often in conjunction with the use of hyperpolarizing offsets to the cell under test to suppress ongoing bursting. 4. For each class, the network of synaptic interconnections among the pyloric-system neurons was shown to not be the cause of the regenerative responses observed. 5. Plateau potentials are viewed as a driving force for axon spiking during bursts and as interacting with the synaptic network in the formation of the pyloric motor pattern.J Neurophysiol 1982484e 914-37XRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=6747678$Russell, D. F. Hartline, D. K.Synaptic regulation of cellular properties and burst oscillations of neurons in gastric mill system of spiny lobsters, Panulirus interruptusAnimal Barium/pharmacology Comparative Study Electrophysiology Ganglia/cytology/*physiology In Vitro Interneurons/physiology Lobsters/*physiology Motor Neurons/*physiology Periodicity Strontium/pharmacology Support, U.S. Gov't, P.H.S. Synapses/physiologyThe properties of neurons in the stomatogastric ganglion (STG) participating in the pattern generator for the gastric mill rhythm were studied by intracellular current injection under several conditions: during ongoing gastric rhythms, in the nonrhythmic isolated STG, after stimulation of the nerve carrying central nervous system (CNS) inputs to the STG, or under Ba2+ or Sr2+. Slow regenerative depolarizations during ongoing rhythms were demonstrated in the anterior median, cardiopyloric, lateral cardiac, gastropyloric, and continuous inhibitor (AM, CP, LC, GP, and CI) neurons according to criteria such as voltage dependency, burst triggering, and termination by brief current pulses, etc. Experiments showed that regenerative-like behavior was not due to synaptic network interactions. The slow regenerative responses were abolished by isolating the stomatogastric ganglion but could be reestablished by stimulating the input nerve. This indicates that certain CNS inputs synaptically induce the regenerative property in specific gastric neurons. Slow regenerative depolarizations were not demonstrable in gastric mill (GM) motor neurons. Their burst oscillations and firing rate were instead proportional to injected current. CNS inputs evoked a prolonged depolarization in GM motor neurons, apparently by a nonregenerative mechanism. All the gastric cells showed prolonged regenerative potentials under 0.5-1.5 mM Ba2+. We conclude that the gastric neurons of the STG can be divided into three types according to their properties: those with a regenerative capability, a repetitively firing type, and a nonregenerative "proportional" type. The cells are strongly influenced by several types of CNS inputs, including "gastric command fibers."6747678J Neurophysiol 1984521 54-73.85236112Russell, D. F.ngNeural basis of teeth coordination during gastric mill rhythms in spiny lobsters, Panulirus interruptuseAction Potentials Animal Feeding Behavior/physiology Gastrointestinal Motility Lobsters/*physiology Motor Neurons/physiology Support, U.S. Gov't, P.H.S. Synapses/physiology Tooth/*innervationsMotoneurones that drive the closing of the lateral teeth during gastric mill rhythms in spiny lobsters start firing before the motoneurones that drive the medial tooth powerstroke. This has the expected behavioural interpretation that the lateral teeth must close on a food particle before the medial tooth is pulled across it. The neural basis of the teeth coordination was examined. Experiments were made during gastric rhythms in in vitro preparations comprising the stomatogastric, oesophageal and (paired) commissural ganglia. Identified neurones in the stomatogastric ganglion were polarized to study their functional effects on the phasing and amplitude of bursts in other cells. Evoked firing of the lateral teeth closer motoneurones (especially LC) would evoke a discharge in the medial tooth powerstroke (GM) motoneurones, and suppress the firing of the medial tooth returnstroke (CP) motoneurone. Therefore the coordination pathway starts directly with the lateral teeth closer motoneurones. The CI interneurone was found to be an important link in the coordination pathway. It exerted opposite effects on the medial tooth motoneurones, suppressing firing of the powerstroke GM cells while evoking bursts in the returnstroke CP cell. CI affected other features of the pattern as well. Non-spiking inhibition from the lateral teeth closer motoneurones (LC and GP) to the lateral teeth opener motoneurones (LGs) was found to occur conjointly with spike-mediated IPSPs. Hyperpolarization of the LC, GP or CI neurones could temporarily abolish the gastric rhythm, but bursting in some or all of the other cells would eventually return, although in some cases the phase pattern was altered. It appears that no individual neurone in the gastric network is necessary for rhythm production. The coordination system can be viewed as several 'levels' of synaptic connections, each level being redundant and synergistic with the others. J Exp Biol 1985 114 99-119 Russell, D.F. 1985_Pattern and reset analysis of the gastric mill rhythm in a spiny lobster, Panulirus interruptusoJ J Exp Biol 114 71-98o Russell, D.F. Graubard, K. 1987& Cellular and synaptic properties "Selverston, A.I. Moulins, M.*$The Crustacean Stomatogastric System Berlin Springer-Verlag 79-100 Schaefer, N. 1970JThe functional morphology of the fore-gut of three species of decapod Crustacea: Cyclograpsus punctatus Milne-Edwards, Biogenes brevirostris Stimpson, and Upogebia africana OrtmannaQhx Zool Africanad52309-326 Schmitz, E.H. 1986vCephalothoracic muscles of the foregut and feeding appendages of Armadillidiom vulgare (Latreill) (Crustacea: Isopoda)AV J Crust Biol6y134-142DB%$B&A(78654321?141348390387169768 (U.S.)Qp370 .c77 1986T^WThe Crustacean stomatogastric system : a model for the study of central nervous systems Berlin ; New York Springer-Verlagr 1986xvi, 338ng86020429 edited by Allen I. Selverston and Maurice Moulins. Includes index. Bibliography: p. [314]-332.tmCentral nervous system Congresses. Animal models in research Congresses. Crustacea Nervous system Congresses.2,%Selverston, Allen I. Moulins, Maurice.Selverston, A.I. 1987\VThe Crustacean Stomatogastric System: A Model for The Study of Central Nervous Systems "Selverston, A.I. Moulins, M. Berlin Springer-Verlagc 338 *$The Crustacean Stomatogastric SystemSelverston, A.I. 1987"Motor control, invertebrates"Encyclopedia of Neuroscience Boston  Birkhauser695-697Selverston, A.I. 1988\VA consideration of invertebrate central pattern generators as computational data basesJ Neural Networks1109-117Selverston, A.I. 1988JCInvertebrate central pattern generators as computational data bases "Mandell Schlessinger Kelson*#Dynamic Patterns in Complex Systems World Scientific PressSelverston, A.I. 1988*#The lobster gastric mill oscillator  Jacklet, J.(!Neuronal and Cellular Oscillators New York  Marcel Dekker339-370Selverston, A.I. 1988jdSwitching among functional states by means of neuromodulators in the lobster stomatogastric ganglion  Camhi, J. Invertebrate Neuroethology  Experentia44376-382O"Selverston, A.I. Mazzoni, P. 1989>7Flexibility of computational units in invertebrate CPGst Durbin Miall MitchisonThe Computing Neuron  Massachusettso Addison WesleySelverston, A.I. 1995:4Modulation of circuits underlying rhythmic behaviorsJ Comp Physiol A 179139-147B;Selverston, A.I. Panchin, Y. Archavsky, Y.I. Orlovsky, G.N. 1997@:Shared features of invertebrate central pattern generators >8Stein, P.S.G. Grillner, S. Selverston, A.I. Stuart, D.G.*#Neuron, Networks and Motor BehaviorU  Cambridge, MAh  MIT Pressy105-117rXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=9928300F@Selverston, A. Elson, R. Rabinovich, M. Huerta, R. Abarbanel, H.RKBasic principles for generating motor output in the stomatogastric ganglionaAnimal Ganglia, Invertebrate/cytology/physiology Lobsters/*physiology Motor Neurons/*physiology Nervous System Physiology *Periodicity Stomach/innervationvpThe lobster stomatogastric ganglion contains 30 neurons and when modulated can produce two distinct rhythmic motor patterns--the gastric mill and the pyloric. The complete neural circuitry underlying both patterns is well known. Without modulatory input no patterns are produced, and the neurons fire tonically or are silent. When neuromodulators are released into the ganglion from specific neurons or are delivered as hormones, the properties of the neurons and synapses change dramatically and modulator-specific gastric mill and pyloric patterns are produced. In general the rhythmicity derives from the induced burstiness of the neurons, and the pattern from the strengths of the electrical and chemical synapses. The organized activity can be traced to a marked reduction of chaotic activity in individual neurons when they shift from the unmodulated to the modulated state.'^WInstitute of Neurobiology, San Juan, Puerto Rico 00901. A_SELVERSTON@RCMACA.UPR.CLU.EDU9928300Ann N Y Acad Sci 1998 860 35-50.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10635721Selverston, A.\VGeneral principles of rhythmic motor pattern generation derived from invertebrate CPGsAnimal Invertebrates/*physiology Models, Neurological Motor Activity/*physiology Movement/*physiology Nerve Net/physiology Neurons/*physiology Oscillometry Synapses/physiologyE'^WInstitute of Neurobiology, University of Peurto Rico, San Juan. al@neurobio.upr.clu.edu 10635721 1999Prog Brain Res 123o 247-57 Using Smart Source ParsingZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10643473Selverston, A.@9What invertebrate circuits have taught us about the brainAnimal Brain/*physiology History of Medicine, 20th Cent. Invertebrates/*physiology *Nervous System Physiology Neural Pathways/physiology Neurosciences/history'LEInstitute of Neurobiology, San Juan PR 00901. al@neurobio.upr.clu.edun10643473Brain Res Bull 199950 5-60439-40.7ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11165906nrkSelverston, A. I. Rabinovich, M. I. Abarbanel, H. D. Elson, R. Szucs, A. Pinto, R. D. Huerta, R. Varona, P.opjReliable circuits from irregular neurons: a dynamical approach to understanding central pattern generatorsAnimal Ganglia, Invertebrate/*physiology In Vitro Lobsters *Models, Neurological Nerve Net/physiology Neurons/*physiology Nonlinear Dynamics Synapses/physiology Synaptic Transmission/physiologyCentral pattern generating neurons from the lobster stomatogastric ganglion were analyzed using new nonlinear methods. The LP neuron was found to have only four or five degrees of freedom in the isolated condition and displayed chaotic behavior. We show that this chaotic behavior could be regularized by periodic pulses of negative current injected into the neuron or by coupling it to another neuron via inhibitory connections. We used both a modified Hindmarsh-Rose model to simulate the neurons behavior phenomenologically and a more realistic conductance-based model so that the modeling could be linked to the experimental observations. Both models were able to capture the dynamics of the neuron behavior better than previous models. We used the Hindmarsh-Rose model as the basis for building electronic neurons which could then be integrated into the biological circuitry. Such neurons were able to rescue patterns which had been disabled by removing key biological neurons from the circuit.'Institute for Nonlinear Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0402, USA. aselverston@ucsd.edu 11165906J Physiol Parisc 200094 5-6 357-74.r82Sen, K. Jorge-Rivera, J.C. Marder, E. Abbott, L.F. 1996Decoding synapses J Neurosci16 6307-6318! l98143581<5Scholz, N. L. Chang, E. S. Graubard, K. Truman, J. W.ZTThe NO/cGMP pathway and the development of neural networks in postembryonic lobsters~xAnimal Central Nervous System/drug effects/enzymology/growth & development Cyclic GMP/*physiology Female Ganglia, Invertebrate/drug effects/enzymology/growth & development Larva Lobsters/growth & development/*physiology Molsidomine/analogs & derivatives/pharmacology Nerve Net/*growth & development Nerve Tissue Proteins/analysis Neuronal Plasticity Nitric Oxide/*physiology Nitric-Oxide Synthase/analysis Nitroprusside/pharmacology Penicillamine/analogs & derivatives/pharmacology Signal Transduction/drug effects Smell/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. 1-Methyl-3-isobutylxanthine/pharmacologyThe nitric oxide/cyclic 3',5'-guanosine monophosphate (NO/cGMP) signaling pathway has been implicated in certain forms of developmental and adult neuronal plasticity. Here we use whole-mount immunocytochemistry to identify components of this pathway in the nervous system of postembryonic lobsters as they develop through metamorphosis. We find that the synthetic enzyme for NO (nitric oxide synthase, or NOS) and the receptor for this transmitter (NO-sensitive soluble guanylate cyclase) are broadly distributed in the central nervous system (CNS) at hatching. In the brain, NOS immunoreactivity is intensified during glomerular development in the olfactory and accessory lobes. Whereas only a few neurons express NOS in the CNS, many more neurons synthesize cGMP in the presence of NO. NO-sensitive guanylate cyclase activity is a stable feature of some cells, while in others it is regulated during development. In the stomatogastric nervous system, a subset of neurons become responsive to NO at metamorphosis, a time when larval networks are reorganized into adult motor circuits. cGMP accumulation was occasionally detected in the nucleus of many cells in the CNS, which suggests that cGMP may have a role in transcription. Based on these findings, we conclude that the NO/cGMP signaling pathway may participate in the development of the lobster nervous system. Furthermore, NO may serve as a modulatory neurotransmitter for diverse neurons throughout the CNS. J Neurobiol 1998343 208-26+CP*)@('" b<5Scholz, N. L. de Vente, J. Truman, J. W. Graubard, K.0*Neural network partitioning by NO and cGMP<6Animal Arginine/pharmacology Citrulline/metabolism Crabs Cyclic GMP/*metabolism Digestive System/innervation Enzyme Inhibitors/pharmacology Fluorescent Dyes Ganglia, Invertebrate/cytology/drug effects/*metabolism Guanylate Cyclase/antagonists & inhibitors/metabolism Immunohistochemistry In Vitro Isoquinolines Male Nerve Net/drug effects/*metabolism Neurons/classification/cytology/drug effects/metabolism Neurotransmitters/metabolism Nitric Oxide/*metabolism Nitric Oxide Donors/pharmacology Periodicity Signal Transduction/drug effects Support, U.S. Gov't, P.H.S.6/The stomatogastric ganglion (STG) of the crab Cancer productus contains approximately 30 neurons arrayed into two different networks (gastric mill and pyloric), each of which produces a distinct motor pattern in vitro. Here we show that the functional division of the STG into these two networks requires intact NO-cGMP signaling. Multiple nitric oxide synthase (NOS)-like proteins are expressed in the stomatogastric nervous system, and NO appears to be released as an orthograde transmitter from descending inputs to the STG. The receptor of NO, a soluble guanylate cyclase (sGC), is expressed in a subset of neurons in both motor networks. When NO diffusion or sGC activation are blocked within the ganglion, the two networks combine into a single conjoint circuit. The gastric mill motor rhythm breaks down, and several gastric neurons pattern switch and begin firing in pyloric time. The functional reorganization of the STG is both rapid and reversible, and the gastric mill motor rhythm is restored when the ganglion is returned to normal saline. Finally, pharmacological manipulations of the NO-cGMP pathway are ineffective when descending modulatory inputs to the STG are blocked. This suggests that the NO-cGMP pathway may interact with other biochemical cascades to partition rhythmic motor output from the ganglion. 'voUniversity of Washington, Department of Zoology, Seattle, Washington 98195-1800, USA. Nathaniel.Scholz@noaa.gova11222651http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11222651 http://www.jneurosci.org/cgi/content/full/21/5/1610 http://www.jneurosci.org/cgi/content/abstract/21/5/1610t J Neurosci 2001215v1610-8. Selverston, A.I. 1973TMThe use of intracellular dye injections in the study of small neural networks Kater Nicholson,&Intracellular Staining in Neurobiology New York Springer-Verlage255-280cSelverston, A.I. 1974leStructural and functional basis of motor pattern generation in stomatogastric ganglion of the lobster Am Zoole74957-972$Selverston, A.I. Mulloney, B.n 1974jcOrganization of the stomatogastric ganglion of spiny lobster. II. Neurons driving the medial toothJ Comp Physiol91 33-51pSelverston, A.I. 197681A model system for the study of rhythmic behavior Fentress, J.C.$Simpler Networks and Behavior Sunderland, MA Sinauer Associates, Inc. 82-98iSelverston, A.I. 1976RKNeuronal mechanisms for rythmic motor pattern generation in a simple system :4Herman, R.M. Grillner, S. Stein, P.S.G. Stuart, D.G."Neural Control of Locomotion New York  Plenum Press377-399t770588914.Selverston, A. I. Russell, D. F. Miller, J. P.ZSThe stomatogastric nervous system: structure and function of a small neural networkXQAction Potentials Animal Ganglia/cytology/*physiology Interneurons/physiology Lobsters/*physiology Models, Neurological Motor Neurons/physiology Muscle, Smooth/innervation Neural Pathways/physiology Neurotransmitters/physiology Pylorus/innervation/physiology Stomach/innervation/physiology Support, U.S. Gov't, P.H.S. Synapses/physiologyt 1976Prog Neurobiol7t3s 215-90 Using Smart Source ParsingSelverston, A.I. 1977HAMechanisms for the production of rhythmic behavior in crustaceans  Hoyle, G.4-Identified Neurons and Behavior of Arthropods New York  Plenum Press209-225o 0> ,/z=<;:9r.-,N78048124Selverston, A. I.:4Neural circuitry underlying oscillatory motor outputAnimal Ganglia/cytology/*physiology Interneurons/physiology Lobsters/*physiology Motor Neurons/*physiology Nerve Net/*physiology Nervous System/*physiology *Nervous System Physiology Neural Inhibition *Periodicity Stomach/innervation Synapses/physiologyA1. The stomatogastric nervous system of lobsters can be used as a model network with which to study the mechanisms involved in the generation of rhythmic behaviour. 2. The stomatogastric ganglion contains about thirty neurons and produces two rhythms, the gastric and the pyloric. 3. The gastric rhythm appears to be derived from the global properties of a twelve-cell network. 4. The pyloric rhythm is driven by a group of three endogenous bursters. 5. Both rhythms are assisted by phasic excitatory input from the two commissural ganglia. 6. Synapses found in this network appear to be located on the finest dendritic branches and are multiterminal. 1977 J Physiol734 463-70 Using Smart Source ParsingSelverston, A.I. 1979NGMechanisms for the production and modulation of rhythmic motor patterns:3The Selection and Modulation of Behavioral Programs  Cambridge, MA  MIT Presss 45-472Selverston, A.I. 19804.Information processing and synaptic morphology Pinkser, H. Willis, W.2,Information Processing in the Nervous System New York  Raven Press 91-10881095906&Selverston, A. I. Miller, J. P. Mechanisms underlying pattern generation in lobster stomatogastric ganglion as determined by selective inactivation of identified neurons. I. Pyloric systemAction Potentials Animal Ganglia/cytology/*physiology Lobsters/*physiology Neurons/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Synaptic Transmissiont1. Four factors contribute to pattern generation in the pyloric network of the lobster stomatogastric ganglion. These are: a) endogenously oscillating neurons; b) synaptic network properties; c) nonlinear cellular properties, including the generation of plateau potentials; and d) excitatory input from the commissural ganglia. The roles and relative importance of these factors were investigated with a new technique for inactivating single specific identified neurons. 2. In stomatogastric ganglia in which the excitatory input is left intact, a) pattern generation continues when any cell or pair of cells other than the endogenous bursters are inactivated, b) pattern generation also continues when the endogenous bursters are inactivated, c) pattern generation ceases when the endogenous bursters plus one other particular cell are inactivated. This cell, although not an endogenous burster, displays a strong tendency to generate plateau potentials. 3. In stomatogastric ganglia that have been isolated from excitatory input, a) pattern generation continues when any cell or pair of cells other than the endogenous bursters are inactivated, b) pattern generation ceases when the endogenous bursters are inactivated. 4. Some of the inputs to the stomatogastric ganglion normally fire in bursts. However, their potentiation and acceleration of the output pattern are also produced by tonic stimulation of the nerve. The effect of one of those inputs is mimicked by bath application of dopamine to the stomatogastric ganglion. 5. The roles and importance of the three most important factors were qualitatively summarized in a chart specifying the activity of the network as a function of its intactness.J Neurophysiol 19804461102-21$Selverston, A.I. Miller, J.P.c 1982XRApplication of a cell inactivation technique to the study of small neural networks TINS5120-123843007882,Selverston, A. I. Miller, J. P. Wadepuhl, M.F?Cooperative mechanisms for the production of rhythmic movementsuAction Potentials Animal Ganglia/*physiology Lobsters/physiology Models, Neurological Mouth/physiology *Movement Neurons/*physiology Stomach/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiology' 1983Symp Soc Exp Biol-37 55-87r Using Smart Source Parsing0*Selverston, A.I. Miller, J.P. Wadepuhl, M. 1983D=Neural mechanisms for the production of cyclic motor patternsIEEE Transactions, SMC13749-7570*Selverston, A.I. Miller, J.P. Wadepuhl, M. 1983BZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11840478i>7Skiebe, P. Dreger, M. Meseke, M. Evers, J. F. Hucho, F.t|vIdentification of orcokinins in single neurons in the stomatogastric nervous system of the crayfish, Cherax destructor Animal Crayfish/*metabolism Female Immunohistochemistry Male Nervous System/*metabolism Neurons/*metabolism Neuropeptides/*metabolism Pericardium/metabolism Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Stomach/*innervation Support, Non-U.S. Gov't. b [The orcokinins are a highly conserved family of crustacean peptides that enhance hindgut contractions in the crayfish Orconectes limosus (Stangier et al. [1992] Peptides 13:859-864). By combining immunocytochemical and mass spectrometrical analysis of the stomatogastric nervous system (STNS) in the crayfish Cherax destructor, we show that multiple orcokinins are synthesized in single neurons. Immunocytochemistry demonstrated orcokinin-like immunoreactivity in all four ganglia of the STNS and in the pericardial organs, a major neurohaemal organ. Identified neurons in the STNS were stained, including a pair of modulatory interneurons (inferior ventricular nerve neuron, IVN), a neuron with its cell body in the stomatogastric ganglion that innervates cardiac muscle c6 via the anterior median nerves (AM-c6), and a sensory neuron (anterior gastric receptor neuron). Five orcokinin-related peptides were identified by matrix- assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) post source decay fragmentation in samples of either the stomatogastric ganglion or the pericardial organs. Four of these peptides are identical to peptides derived from the cloned Procambarus clarkii precursor (Yasuda-Kamatani and Yasuda [2000] Gen. Comp. Endocrinol. 118:161-172), including the original [Asn(13)]-orcokinin (NFDEIDRSGFGFN, [M+H](+) = 1,517.7 Da), [Val(13)]-orcokinin ([M+H](+) = 1,502.7 Da), [Thr(8)-His(13)]-orcokinin ([M+H](+) = 1,554.8 Da), and FDAFTTGFGHS ([M+H](+) = 1,186.5 Da). The fifth peptide is a hitherto unknown orcokinin variant: [Ala(8)-Ala(13)]-orcokinin ([M+H](+) = 1,458.7 Da). The masses of all five peptides were also detected in the inferior ventricular nerve of C. destructor, which contains the cell bodies and axons of the IVNs as well as the axons of two other orcokinin-like immunoreactive neurons. In the oesophageal nerve, in which all the orcokinin-like immunoreactivity derives from the IVNs, at least two of the orcokinins were detected, indicating that multiple orcokinins are synthesized in these neurons. Similarly, all four orcokinin masses were detected in the anterior median nerves, in which all the orcokinin-like immunoreactivity derives from the AM-c6 neuron. This study therefore lays the groundwork to investigate the function of the orcokinin peptide family using single identified neurons in a well- studied system.'jcInstitut fur Biologie, Freie Universitat Berlin, D-14195 Berlin, Germany. skiebe@zedat.fu-berlin.de11840478 J Comp Neurol 2002 4443245-59.T [f_http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.cob.org.uk/JEB/194/1/jeb9360.html,0oSkiebe, P. Schneider, H.Allatostatin Peptides in the Crab Stomatogastric Nervous System: Inhibition of the Pyloric Motor Pattern and Distribution of Allatostatin-Like ImmunoreactivityeThe effects of four Diploptera punctata allatostatin peptides on the stomatogastric nervous system of the crab Cancer borealis were studied. All of the peptides had similar actions on the activity of neurons involved in rhythmic movements of the pyloric region of the stomach, decreasing the frequency of the pyloric rhythm in a dose-dependent manner. Diploptera allatostatin 3 (D-AST-3) was slightly more effective than the others. The absolute change in the frequency of the pyloric rhythm depended on the starting frequency, demonstrating that the effect of D-AST-3 depends on the preceding physiological state of the preparation. The largest decreases were observed when the starting frequency was slower than 0.8 Hz. Whole-mount immunocytochemistry with anti-Diploptera allatostatin 1 antibodies demonstrated the presence of allatostatin-like peptides in the paired commissural ganglia, the unpaired oesophageal ganglion and the stomatogastric ganglion, and in their connecting and motor nerves. Dense processes were labeled in the stomatogastric ganglion, 12­19 cell bodies and neuropil staining were found in each commissural ganglion, two cell bodies were stained in the oesophageal ganglion and two pairs of cell bodies, the gastropyloric receptor neurons, were stained in peripheral nerves. 1994 J Exp Biol 194 1d195-208p Using Smart Source ParsingZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10075445* Skiebe, P.Allatostatin-like immunoreactivity in the stomatogastric nervous system and the pericardial organs of the crab Cancer pagurus, the lobster Homarus americanus, and the crayfish Cherax destructor and Procambarus clarkiiAnimal Comparative Study Crabs/*metabolism Crayfish/*metabolism Digestive System/*innervation Female Immunohistochemistry Lobsters/*metabolism Male Nervous System/metabolism Neuropeptides/*metabolism Support, Non-U.S. Gov't Tissue DistributionThe distribution of allatostatin (AST)-like immunoreactivity was studied in the stomatogastric nervous system (STNS) and the neurosecretory pericardial organs (PO) of four decapod crustacean species by using wholemount immunocytochemical techniques and confocal microscopy. AST-like immunoreactivity was found within the STNS of all four species; its distribution in each was unique. In all four species, AST-like immunoreactivity was present in the paired commissural ganglia (CoG), in the esophageal ganglion (OG), in the stomatogastric ganglion (STG), and in their connecting nerves. Within the CoGs, numerous cell bodies and neuropil were stained. In the OG, two cell bodies were immunoreactive, although their branching pattern varies between species. In the STG of C. pagurus and H. americanus, neuropil was stained extensively, but no labeled cell bodies were found. Surprisingly, in C. destructor and P. clarkii, cell bodies were stained in the STG, one brightly stained cell body in both species and an additional two to five weakly stained cell bodies in P. clarkii. In all four species, stained gastropyloric receptor cells were present. In contrast to the variable staining within the STNS, all four species have a similar pattern of AST-like immunoreactivity within the PO. Only in C. destructor, AST-immunoreactive varicosities occur on the surface of the circumesophageal connectives and on the postesophageal commissure and suggest another neurohaemal source for AST-like peptides in this species. The pattern of this staining suggests that AST-like peptides are likely utilized as both neurohormones and as neuromodulators in the STNS of decapod crustacea.'^XInstitut fur Neurobiologie, Freie Universitat Berlin, Germany. skiebe@zedat.fu-berlin.de10075445 J Comp Neurol 1999 403185-105. fgedcba`<^_B941002782+Skinner, F. K. Turrigiano, G. G. Marder, E..PIFrequency and burst duration in oscillating neurons and two-cell networkseAnimal Calcium Channels/physiology Cells, Cultured Ganglia/*physiology Mathematics Membrane Potentials *Models, Neurological Neurons/*physiology Oscillometry Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Synapses/physiologyb[We study the relationship of injected current to oscillator period in single neurons and two-cell model networks formed by reciprocal inhibitory synapses. Using a Morris-Lecar-like model, we identify two qualitative types of oscillatory behavior for single model neurons. The "classical" oscillator behavior is defined as type A. Here the burst duration is relatively constant and the frequency increases with depolarization. For oscillator type B, the frequency first increases and then decreases when depolarized, due to the variable burst duration. Our simulations show that relatively modest changes in the maximal inward and outward conductances can move the oscillator from one type to another. Cultured stomatogastric ganglion neurons exhibit both A and B type behaviors and can switch between the two types with pharmacological manipulation. Our simulations indicate that the stability of a two-cell network with injected current can be extended with inhibitory coupling. In addition, two-cell networks formed from type A or type B oscillators behave differently from each other at lower synaptic strengths. 1993 Biol Cybern 69 5-6  375-83 Using Smart Source Parsing96384338*$Skinner, F. K. Kopell, N. Marder, E.haMechanisms for oscillation and frequency control in reciprocally inhibitory model neural networksaAnimal Membrane Potentials/*physiology Motor Activity/*physiology *Neural Networks (Computer) Neurons/*physiology Presynaptic Terminals/physiology Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.We describe four different mechanisms that lead to oscillations in a network of two reciprocally inhibitory cells. In two cases (intrinsic release and intrinsic escape) the frequency of the network oscillation is insensitive to the threshold voltage of the synaptic potentials. In the other two cases (synaptic release and synaptic escape) the network frequency is strongly determined by the threshold voltage of the synaptic connections. The distinction between the different mechanisms blurs as the function describing synaptic activation becomes less steep and as the model neurons are removed from the relaxation regime. These mechanisms provide insight into the parameters that control network frequency in motor systems that depend on reciprocal inhibition.J Comput Neurosci 19941 1-2 69-87ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11224547iB7Organization of the crayfish oesophageal nervous systemiJ Comp Physiol 102t237-249  Spruston, N. Nusbaum, M.P. 1991}Cyclic nucleotide-mediated modulation of the pyloric motor pattern in the stomatogastric ganglion of the crab Cancer borealistn Biol Bull  181 329-330u Storch, V. 1989tmScanning and transmission electron microscopic observations on the stomach of three Mysid species (Crustacea) J Morphol 200 17-27Suh, H.-L. Nemoto, T. 1988B;Morphology of the gastric mill in ten species of euphausidsMar Biol97 79-8578222447Sullivan, R. E. ~wStimulus-coupled 3H-serotonin release from identified neurosecretory fibers in the spiny lobster, Panulirus interruptusAction Potentials Animal Calcium/pharmacology Electric Stimulation Lobsters Neurosecretory Systems/*secretion Potassium/pharmacology Serotonin/*secretion Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.yLife Sci 197822161429-38u"Suthers, I.M. Anderson, D.T. 1981aFunctional morphology of the mouthparts and gastric mill of Ibacus peronii (Palinura Scyllaridae)h<JAust J Mar Freshw Res356 931-944r Suthers, I.M. 1984aFunctional morphology of the mouthparts and gastric mill in Penaeus plebejus (Decapoda Penaeidae)<LAust J Mar Freshw ResM356785-792 lFl Calcium Channels/*physiologyXRhttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=78231620)Tanner, S. L. Storm, E. E. Bittner, G. D.Maintenance and degradation of proteins in intact and severed axons: implications for the mechanisms of long-term survival of anucleate crayfish axonsActins/metabolism Animal Axons/*physiology Biological Transport Cell Survival Crayfish Denervation Nerve Tissue Proteins/*metabolism Support, Non-U.S. Gov't Time Factors Tubulin/metabolismProtein maintenance and degradation are examined in the severed distal (anucleate) portions of crayfish medial giant axons (MGAs), which remain viable for over 7 months following axotomy. On polyacrylamide gels, the silver-stained protein banding pattern of anucleate MGAs severed from their cell bodies for up to 4 months remains remarkably similar to that of intact MGAs. At 7 months postseverance, some (but not all) proteins are decreased in anucleate MGAs compared to intact MGAs. To determine the half-life of axonally transported proteins, we radiolabeled MGA cell bodies and monitored the degradation of newly synthesized transported proteins. Assuming exponential decay, proteins in the fast component of axonal transport have an average half-life of 14 d in anucleate MGAs and proteins in the slow component have an average half-life of 17 d. Such half-lives are very unlikely to account for the ability of anucleate MGAs to survive for over 7 months after axotomy.'@9Department of Zoology, University of Texas, Austin 78712.7823162a J Neurosci 199515 1 Pt 2 540-8..l@=Cholecystokinin/analysis/antagonists & inhibitors/isolation &purification/*physiology94233383.'Turrigiano, G. Abbott, L. F. Marder, E.lPJActivity-dependent changes in the intrinsic properties of cultured neurons$Animal Calcium/physiology Cells, Cultured Egtazic Acid/analogs & derivatives/pharmacology Electric Stimulation Electrophysiology Ganglia, Invertebrate/cytology Lobsters Membrane Potentials Neurites/physiology Neurons/cytology/*physiology Support, U.S. Gov't, P.H.S. Synapses/physiologyuD>Learning and memory arise through activity-dependent modifications of neural circuits. Although the activity dependence of synaptic efficacy has been studied extensively, less is known about how activity shapes the intrinsic electrical properties of neurons. Lobster stomatogastric ganglion neurons fire in bursts when receiving synaptic and modulatory input but fire tonically when pharmacologically isolated. Long-term isolation in culture changed their intrinsic activity from tonic firing to burst firing. Rhythmic stimulation reversed this transition through a mechanism that was mediated by a rise in intracellular calcium concentration. These data suggest that neurons regulate their conductances to maintain stable activity patterns and that the intrinsic properties of a neuron depend on its recent history of activation.Science 1994 264 5161 974-7tNonnotte1990Nonnotte1991hNonnotte1993 Norman1977 Norman1977 Norris1994 Norris1996/ Norris19999 Nott19844% Nozdrachev2000 Nusbaum1988 Nusbaum1988~ Nusbaum1989 Nusbaum1989 Nusbaum1989 Nusbaum1989b Nusbaum1991c Nusbaum1992 Nusbaum1992 Nusbaum1992 Nusbaum1993` Nusbaum1994b Nusbaum1994 Nusbaum1994 Nusbaum19940 Nusbaum1995a Nusbaum1995 Nusbaum1996$ Nusbaum19971 Nusbaum1997P Nusbaum1997 Nusbaum1997| Nusbaum1998 Nusbaum1998# Nusbaum1999/ Nusbaum19992 Nusbaum1999 Nusbaum2000h Nusbaum2000 Nusbaum2000 Nusbaum2001 Nusbaum2002 Nusbaum2002 Nusbaum2002& Nusbaum2004Q Nusbaum2004 Nusbaum2004 Nusbaum2004 Nusbaum2004 O'Neil1983 O'Neil1986 O'Neil1986G O'Neil1993H O'Neil1993o O'Neil19949 O'Neil1995 Ogden1994 Oliva2003% Olivera1997 Orchard1989AOrlovsky19977OOshinsky1994 Panchin1993 Panchin1994A Panchin1997 Parker1976 Patwardhan1934 Patwardhan1935 Patwardhan1935 Patwardhan1935 Patwardhan1935 Patwardhan1935Paupardin-Tritsch1978Paupardin-Tritsch1980Paupardin-Tritsch1980 Pearson1992 Pearson1998 Peck19919 Peck19929 Peck19939 Peck19939 Peck19949 Peck19959 Peck1997r Peck19979% Peck1997 Peck19989 Peck2001+ Perez-Acevedo2000 Perkel1974 Perkel19818 Pfluger1999 Pinto2000B Pinto2000 Pinto2001k Pinto2003 Powell1974 Powers1973 Prinz2002 Prinz2003 Prinz2003 Prinz2003 Prinz20048 Pulver2002 Pulver20027 Pulver20030 Pulver2003 Pulver20030 Pulver2005 Quigley1990Q Quinlan2004!Quinones2001& Rabinovich1998 Rabinovich1999 Rabinovich2000 Rabinovich2000B Rabinovich2000 Rabinovich2001 Rabinovich2001 Rabinovich2001 Rabinovich2002k Rabinovich2003 Ramirez1992 Raper1979 Raper1979 Raper1980 Raper1983 Raper1988 Rattananont1999 Reddy1935 Reglodi1999 Rehder2004Reichert1990IReichert1991Reichert1992Reichert1994I Reina2003Renaud-LeMasson1993oRenaud-LeMasson1994 Rezer1980 Rezer1983 Rezer1987 Rezer1992#Richards1999wRichards19999Richards1999Richards1999Richards2000Richards20030Richards2003Q Ritt19999  Roberts1996 Roberts1997  Robertson1979  Robertson1979  Robertson1981  Robertson1981 Robertson1981 Robertson1981 Robertson1984I Robie2003 Rodriguez1996  Rodriguez1997 Rosingnol1997 Ross19851 Ross1989` Rothman1994 Rowat1991 Rowat1993 Rowat1997 Royer1987! Ruiz2001r Russell1976C Russell1976 Russell1977 Russell1978 Russell1979 Russell1981 Russell1982 Russell1984 Russell1984 Russell1985 Russell1985 Russell1987 Russell1988 Sallee197006 Samoilova2003Schaefer1970W Schmidt1999  Schmitz1986C Schmitz1989[ Schneider1994 Scholtz2003# Scholz1996! Scholz1998 Scholz2000" Scholz2001 Schulz20040 Sellereit2004s Selverston1972 Selverston1972' Selverston1973 Selverston1974 Selverston1974( Selverston1974@ Selverston1974 Selverston1975) Selverston1976* Selverston1976C Selverston1976 Selverston1977+ Selverston1977, Selverston1977 Selverston1979 Selverston1979k Vnopyridine12626616893 2003 Mar\USynaptic modulation of the interspike interval signatures of bursting pyloric neurons1363-77The pyloric network of the lobster stomatogastric nervous system is one of the best described assemblies of oscillatory neurons producing bursts of action potentials. While the temporal patterns of bursts have been investigated in detail, those of spikes have received less attention. Here we analyze the intraburst firing patterns of pyloric neurons and the synaptic interactions shaping their dynamics in millisecond time scales not performed before. We find that different pyloric neurons express characteristic, cell-specific firing patterns in their bursts. Nonlinear analysis of the interspike intervals (ISIs) reveals distinctive temporal structures ('interspike interval signatures'), which are found to depend on the synaptic connectivity of the network. We compare ISI patterns of the pyloric dilator (PD), lateral pyloric (LP), and ventricular dilator (VD) neurons in 1) normal conditions, 2) after blocking glutamatergic synaptic connections, and 3) in various functional configurations of the three neurons. Manipulation of the synaptic connectivity results in characteristic changes in the ISI signatures of the postsynaptic neurons. The intraburst firing pattern of the PD neuron is regularized by the inhibitory synaptic connection from the LP neuron as revealed in current-clamp experiments and also as reconstructed with a dynamic clamp. On the other hand, mutual inhibition between the LP and VD neurons tend to produce more irregular bursts with increased spike jitter. The results show that synaptic interactions fine-tune the output of pyloric neurons. The present data also suggest a way of processing of synaptic information: bursting neurons are capable of encoding incoming signals by altering the fine structure of their intraburst spike patterns.'Institute for Nonlinear Science and Department of Physics and Marine Research Laboratory, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0402.RKSzucs, A. Pinto, R. D. Rabinovich, M. I. Abarbanel, H. D. Selverston, A. I.("22514258 0022-3077 Journal ArticleJ Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12626616 l89310695*#Turrigiano, G. G. Selverston, A. I. \UCholecystokinin-like peptide is a modulator of a crustacean central pattern generatorGAnimal Brain/*physiology Cholecystokinin/metabolism/*physiology Immunohistochemistry Lobsters/*physiology Nervous System/metabolism Pylorus/innervation Stomach/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.tThe presence, release, and physiological effects of a cholecystokinin(CCK)-like peptide within the stomatogastric ganglion (STG) of the lobster, Panulirus interruptus, are described. Indirect immunofluorescence with 2 antisera raised against CCK8 was used to determine the distribution of CCK-like immunoreactivity (CCKLI) in the stomatogastric nervous system. CCKLI was demonstrated in the input nerve and the neuropil of the STG and in neuropil and somata in the commissural ganglia (CGs), brain, and eyestalks. None of the somata within the STG displayed CCKLI. The cross-reactivities of the CCK antisera with several peptides were determined using either a radioimmunoassay or an immunoblot assay; the antisera recognized peptides homologous to CCK but did not cross-react significantly with several unrelated peptides. The STG contains 2 central pattern generators (CPGs), the pyloric and the gastric mill CPGs. Bath application of CCK8 to the STG had modulatory effects on both CPGs, which were dose dependent and reversible. CCK increased the spike frequencies and number of spikes per burst of the pyloric rhythm but had little effect on the period. CCK increased the period of the gastric rhythm and produced changes in the spike frequencies, burst lengths, and phases of gastric units. High concentrations of peptide were needed to produce these effects (10(-6) to 10(-4) M). Finally, stimulation of the stomatogastric nerve (stn), which contains fibers immunoreactive to CCK, produced calcium-dependent release of CCK molar equivalents (CCKE) into the STG. The stn was electrically stimulated and the superfusate around the ganglion was collected and assayed for CCKE using a radioimmunoassay. Stimulation produced the release of 37.1 +/- 7.1 fmol (mean +/- SEM), compared to 13.7 +/- 4.9 fmol for unstimulated controls and 4.9 +/- 2.9 fmol in the absence of calcium. These data suggest that a CCK-like peptide is an endogenous modulator of the stomatogastric ganglion of P. interruptus. J Neurosci 1989972486-501jji h >\USwensen, A. M. Golowasch, J. Christie, A. E. Coleman, M. J. Nusbaum, M. P. Marder, E.I\UGABA and responses to GABA in the stomatogastric ganglion of the crab Cancer borealisAAnimal Chromatography, High Pressure Liquid Crabs GABA/*metabolism/pharmacology Ganglia, Invertebrate/*metabolism/physiology Immunohistochemistry Microscopy, Confocal Neurons/metabolism/physiology Patch-Clamp Techniques Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.cD=The multifunctional neural circuits in the crustacean stomatogastric ganglion (STG) are influenced by many small-molecule transmitters and neuropeptides that are co-localized in identified projection neurons to the STG. We describe the pattern of gamma-aminobutyric acid (GABA) immunoreactivity in the stomatogastric nervous system of the crab Cancer borealis and demonstrate biochemically the presence of authentic GABA in C. borealis. No STG somata show GABA immunoreactivity but, within the stomatogastric nervous system, GABA immunoreactivity co- localizes with several neuropeptides in two identified projection neurons, the modulatory proctolin neuron (MPN) and modulatory commissural neuron 1 (MCN1). To determine which actions of these neurons are evoked by GABA, it is necessary to determine the physiological actions of GABA on STG neurons. We therefore characterized the response of each type of STG neuron to focally applied GABA. All STG neurons responded to GABA. In some neurons, GABA evoked a picrotoxin-sensitive depolarizing, excitatory response with a reversal potential of approximately -40 mV. This response was also activated by muscimol. In many STG neurons, GABA evoked inhibitory responses with both K(+)- and Cl(-)-dependent components. Muscimol and beta-guanidinopropionic acid weakly activated the inhibitory responses, but many other drugs, including bicuculline and phaclofen, that act on vertebrate GABA receptors were not effective. In summary, GABA is found in projection neurons to the crab STG and can evoke both excitatory and inhibitory actions on STG neurons.'XQVolen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA.10862721http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10862721 http://www.biologists.com/JEB/203/14/jeb2713.html J Exp Biol 2000 203 Pt 142075-92. Swensen, A. M. Marder, E.bxqMultiple peptides converge to activate the same voltage-dependent current in a central pattern-generating circuitsAnimal Biological Clocks/drug effects/*physiology Calmodulin/antagonists & inhibitors Cells, Cultured Crabs Drug Synergism Ganglia, Invertebrate/drug effects/*metabolism In Vitro Invertebrate Hormones/metabolism/pharmacology Ion Channels/drug effects/metabolism Neurons/cytology/drug effects/metabolism Neuropeptides/*metabolism/pharmacology Oligopeptides/metabolism/pharmacology Patch-Clamp Techniques Second Messenger Systems/drug effects Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The stomatogastric ganglion of the crab, Cancer borealis, is modulated by >20 different substances, including numerous neuropeptides. One of these peptides, proctolin, activates an inward current that shows strong outward rectification (Golowasch and Marder, 1992). Decreasing the extracellular Ca(2+) concentration linearizes the current-voltage curve of the proctolin-induced current. We used voltage clamp to study the currents evoked by proctolin and five additional modulators [C. borealis tachykinin-related peptide Ia (CabTRP Ia), crustacean cardioactive peptide, red pigment-concentrating hormone, TNRNFLRFamide, and the muscarinic agonist pilocarpine] in stomatogastric ganglion neurons, both in the intact ganglion and in dissociated cell culture. Subtraction currents yielded proctolin-like current-voltage relationships for all six substances, and the current-voltage curves of all six substances showed linearization in low external Ca(2+). The lateral pyloric neuron responded to all six modulators, but the ventricular dilator neuron only responded to a subset of them. Bath application of saturating concentrations of proctolin occluded the response to CabTRP and vice versa. N-(6-Aminohexyl)-5-chloro-1- napthalensulfonamide, a calmodulin inhibitor, increased the amplitude and altered the voltage dependence of the responses elicited by CabTRP and proctolin. Together, these data indicate that all six substances converge onto the same voltage-dependent current, although they activate different receptors. Therefore, differential network responses evoked by these substances may primarily depend on the receptor distribution on network neurons.'b\Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454, USA.10995818http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10995818 http://www.jneurosci.org/cgi/content/full/20/18/6752 http://www.jneurosci.org/cgi/content/abstract/20/18/6752 J Neurosci 200020186752-9. Swensen, A. M. Marder, E.RKModulators with convergent cellular actions elicit distinct circuit outputssSix neuromodulators [proctolin, Cancer borealis tachykinin-related peptide Ia, crustacean cardioactive peptide (CCAP), red pigment- concentrating hormone, TNRNFLRFamide, and pilocarpine] converge onto the same voltage-dependent inward current in stomatogastric ganglion (STG) neurons of the crab C. borealis. We show here that each of these modulators acts on a distinct subset of pyloric network neurons in the STG. To ask whether the differences in cell targets could account for their differential effects on the pyloric rhythm, we systematically compared the motor patterns produced by proctolin and CCAP. The motor patterns produced in proctolin and CCAP differed quantitatively in a number of ways. Proctolin and CCAP both act on the lateral pyloric neuron and the inferior cardiac neuron. Proctolin additionally acts on the pyloric dilator (PD) neurons, the pyloric (PY) neurons, and the ventricular dilator neuron. Using the dynamic clamp, we introduced an artificial peptide-elicited current into the PD and PY neurons, in the presence of CCAP, and converted the CCAP rhythm into a rhythm that was statistically similar to that seen in proctolin. This suggests that the differences in the network effects of these two modulators can primarily be attributed to the known differential distributions of their receptors onto distinct subsets of neurons, despite the fact that they activate the same current.'^WVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454.11356892http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11356892 http://www.jneurosci.org/cgi/content/full/21/11/4050 http://www.jneurosci.org/cgi/content/abstract/21/11/4050 J Neurosci 200121114050-8.vqpnu2os T2156025632y 1990 FebxhbCharacterization of Ca current underlying burst formation in lobster cardiac ganglion motorneurons 370-84 1. The anterior motorneurons of the cardiac ganglion of Homarus americanus were ligated less than 300 microns from the soma. This removes impulse-generating membrane and sites of synaptic input while preserving the ability of the soma to generate the burst-forming potentials termed "driver potentials" regenerative, slow (250-ms duration) depolarizations (to -20 mV) in response to brief, depolarizing stimuli. At stimulus intervals corresponding to rates of bursting observed in spontaneously active, intact ganglia (0.3-1.2/s), driver potential amplitude increases with increasing stimulus interval. 2. A two-electrode voltage clamp was used to characterize inward current observable from the ligated neurons in tetrodotoxin (TTX)-tetraethylammonium (TEA)-containing salines. The amplitude of inward current shows a hyperbolic relation to [Ca]o that is well fitted by a form of the Michaelis-Menten equation. Inward current is maintained but not augmented when Ca2+ is replaced by Ba2+ or Sr2+. It is concluded that the inward current, to be referred to as ICa, is mediated by voltage-dependent Ca channels. 3. Contamination of ICa by early outward current (IA) was evaluated by addition of 4-aminopyridine (4-AP, 4 mM). In the presence of 4-AP, the net inward current is increased and the potential at which maximum ICa occurs is shifted 10 mV more positive. 4. Subtraction of outward currents recorded in Mn2(+)-containing saline from overall currents in the absence of Mn2+ provided another means to separate inward from outward current. I-V curves from such "Mn-subtracted" records show ICa approaches a saturating value for steps to -5 mV and more depolarized. The time to peak ICa is voltage dependent. The largest inward currents (up to 240 nA) and minimal time to peak (4 ms) are observed for steps from holding potentials of -50 to -60 mV. 5. Decline of ICa during depolarized steps observed in Mn-subtracted records represents inactivation rather than development of competing outward current. Inactivation is slow and incomplete; the rate and fractional amount of inactivation are not directly voltage dependent. Nonsubtracted responses to 500-ms depolarizations to potentials evoking little outward current show that an initial rapid decline of ICa (tau approximately 40 ms) is followed at approximately 80 ms by a slower phase of decline (tau approximately 180 ms). With repetitive clamps, the early phase proved labile.(ABSTRACT TRUNCATED AT 400 WORDS)'f_Bekesy Laboratory of Neurobiology, Department of Zoology, University of Hawaii, Honolulu 96822.Tazaki, K. Cooke, I. M.("90188494 0022-3077 Journal ArticleJ NeurophysiolAnimal Calcium Channels/*physiology Electrophysiology Ganglia/*physiology Motor Neurons/*physiology Nephropidae/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.jdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=215602592177194Tazaki, K. Chiba, C.jcMechanisms underlying burst generation of the pyloric muscle in the mantis shrimp, Squilla oratoriagAnimal Egtazic Acid/pharmacology Electrophysiology Female Ions Male Muscle Contraction Muscles/*physiology Neuromuscular Junction/physiology Oscillometry Shrimp/*physiology Stomach Support, Non-U.S. Gov't Tetrodotoxin/pharmacologyThe pyloric constrictor muscles of the stomach in Squilla can generate spikes by synaptic activation via the motor nerve from the stomatogastric ganglion. Spikes are followed by slow depolarizing afterpotentials (DAPs) which lead to sustained depolarization during a burst of spikes. 1. The frequency of rhythmic bursts induced by continuous depolarization is membrane voltage-dependent. A brief depolarizing or hyperpolarizing pulse can trigger or terminate bursts, respectively, in a threshold-dependent manner. 2. The conductance increases during the DAP response. The amplitude of DAP decreases by imposed depolarization, whereas it increases by hyperpolarization. DAPs from successive spikes sum to produce a sustained depolarizing potential capable of firing a burst. 3. The spike and DAP are reduced in amplitude by decreasing [Ca]o, enhanced by Sr2+ or Ba2+ substituted for Ca2+, and blocked by Co2+ or Mn2+. DAPs are selectively blocked by Ni2+, and the spike is followed by a hyperpolarizing afterpotential. 4. The spike and DAP are prolonged by intracellular injection of the Ca2+ chelator EGTA. A hyperpolarizing afterpotential is abolished by EGTA and enhanced by increasing [Ca]o. The DAP is diminished in Na(+)-free saline and reduced by tetrodotoxin. 5. It is concluded that the muscle fiber is endowed with endogenous oscillatory properties and that the oscillatory membrane events result from changes of a voltage- and time- dependent conductance to Ca2+ and Na+ and a Ca2+ activated conductance to K+.J Comp Physiol [A] 1991 1696 737-50Tazaki, K. Miyazaki, T. 1991Neural control of the posterior cardiac plate and pyloric regions of the matis shrimp, Squilla oratoria: neurogenic and myogenic activities of musclesWgJ Comp Physiol A 168o265-279r Tazaki, K. 1993Motor pattern generation of the posterior cardiac plate-pyloric system in the stomatogastric ganglion of the mantis shrimp Squilla oratoriae{J Comp Physiol A 172]369-387 Tazaki, K. Chiba, C. 1993lCellular properties and modulation of the stomatogastric ganglion neurons of the stomatopod Squilla oratoria\J Comp Physiol A 173o 85-101Tazaki, K. Chiba, C. 1994Glutamate, acetylcholine, and -aminobutyric acid as transmitters in the pyloric system of the stomatogastric ganglion of the stomatopod, Squilla oratoria.J Comp Physiol A 175p487-504Tazaki, K. Tazaki, Y.r 1997f_Neural control of the pyloric region in the foregut of the shrimp Penaeus (Decapoda: Penaeidae)cJ Comp Physiol A 181s367-382aNlsAxons/*ultrastructure14608595 4673 2003 Dec 15Immunocytochemical evidence for nitric oxide- and carbon monoxide-producing neurons in the stomatogastric nervous system of the crayfish Cherax quadricarinatuse293-306oJCNitric oxide (NO) and carbon monoxide (CO) have been shown to serve neuromodulatory roles in both vertebrates and invertebrates. Here, we use antibodies to their respective biosynthetic enzymes, nitric oxide synthase (NOS) and heme oxygenase 2 (HO-2), to map the distribution of putative gas-producing neurons in the stomatogastric nervous system (STNS) of the crayfish Cherax quadricarinatus. In this species, NOS immunolabeling is found in the neuropil of the stomatogastric ganglion (STG). This staining originates from two immunopositive axons that project to the STG through the superior oesophageal and stomatogastric nerves, presumably from cell bodies located in the commissural ganglia (CoGs). HO-2 immunoreactivity is present in small diameter fibers and varicosities in the periphery of nerves located in the anterior portion of the STNS. This labeling originates from approximately 12 somata in each CoG. Transmission electron microscopy done on the nerves of the anterior STNS shows they contain a neuroendocrine plexus. Collectively, our results indicate that NO- and CO-producing neurons are likely to exist in the crayfish STNS. Moreover, these gases appear to be produced by distinct subsets of the neurons present there. The localization of NO to the STG neuropil suggests that it serves as a locally released modulator or is involved in the local release of other substances within this ganglion. The presence of CO in the neurohemal plexus of the anterior STNS suggests that it serves as a circulating hormone or is involved in the control of neuroendocrine release from this plexus.'tnDepartment of Biology, University of Washington, Seattle, Washington 98195-1800, USA. crabman@u.washington.eduJDChristie, A. E. Edwards, J. M. Cherny, E. Clason, T. A. Graubard, K. 0021-9967 Journal Articlep J Comp Neurolllehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14608595omtr 2433414f566p 1986 DecexqCurrents under voltage clamp of burst-forming neurons of the cardiac ganglion of the lobster (Homarus americanus)m1739-62 n hCrustacean cardiac ganglion neuronal somata, although incapable of generating action potentials, produce regenerative, slow (greater than 200 ms) depolarizing potentials reaching -20 mV (from -50 mV) in response to depolarizing stimuli. These potentials initiate a burst of action potentials in the axon and are thus termed driver potentials. The somata of the anterior-most neurons (cells 1 or 2) were isolated by ligaturing for study of their membrane currents with a two-electrode voltage clamp. Inward current is attributed to Ca2+ by reason of dependence of driver potential amplitude on [Ca2+]0, independence of [Na+]0, resistance to tetrodotoxin, and inhibition by Cd (0.2 mM) and Mn (4 mM). Ca-mediated current (ICa) is present at -40 mV. It is optimally activated by a holding potential (Vh) of -50 to -60 mV and by clamps (command potential, Vc) to -10 mV. Time to peak (10-30 ms) and amplitude are strongly voltage dependent. Maximum tail-current amplitudes observed at -70 to -85 mV are ca. 100 nA. Inward tail peaks may not be resolved by our clamp (settling time, 2 ms). Tails relax with a time constant (tau) of approximately equal to 12 ms (at -70 to -85 mV). ICa exhibits inactivation in double pulse regimes. Recovery has a tau of approximately equal to 0.7 s. Tail current analyses indicate an exponential decline (tau approximately equal to 23 ms at -20 mV) toward a maintained amplitude of inward current tails. Analysis of outward currents indicates the presence of three conductance mechanisms having voltage dependences, time courses, and pharmacology similar to those of early outward current (IA), delayed outward current (IK), and outward current (IC) of molluscan neurons. Analysis of tail currents indicates a reversal potential for each of these near -75 mV, indicating that they are K currents. Early outward current, IA, shows a peak at 5 ms followed by rapid decline. Response to a second clamp given within 0.4 s is reduced; recovery is exponential, with a tau of approximately equal to 200 ms (at Vh = -50 mV). The amplitude of IA tested at 0 mV shows activation or deactivation by subthreshold shifts of Vh. The extent and rate of these changes shows voltage dependence (tau approximately equal to 100-500 ms for subthreshold prepulses). At the normal cell resting potential of -50 mV the amplitude of IA is 25% of that tested from -80 mV.(ABSTRACT TRUNCATED AT 400 WORDS)Tazaki, K. Cooke, I. M.("87111740 0022-3077 Journal ArticleJ Neurophysiol4-Aminopyridine Aminopyridines/pharmacology Animal Axons/physiology Calcium/metabolism Electric Stimulation Ganglia/*physiology Ion Channels/physiology Membrane Potentials/drug effects Nephropidae/*physiology Neural Inhibition/drug effects Neurons/physiology Potassium/metabolism Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. *Synaptic Transmission/drug effects Tetrodotoxin/pharmacologyjdhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2433414& Tazaki, K. Miyatani, M. Ando, F. 1986The anatomy and physiology of the stomatogastric nervous system of Squilla. I. The posterior cardiac plate and pyloric systemsJ Comp Physiol A 159A521-533 Tazaki, K. 1988jcThe anatomy and physiology of the stomatogastric nervous system of Squilla. II. The cardiac systemZool Sci5299-309,/physiology Animal12801895 2003 Jun 11xrRelating Network Synaptic Connectivity and Network Activity in the Lobster (Panulirus interruptus) Pyloric NetworkThe lobster pyloric network has a densely interconnected synaptic connectivity pattern, and the role individual synapses play in generating network activity is consequently difficult to discern. We examined this issue by quantifying the effect on pyloric network phasing and spiking activity of removing the Lateral Pyloric (LP) and Ventricular Dilator (VD) neurons, which synapse onto almost all pyloric neurons. A confounding factor in this work is that LP and VD neuron removal alters pyloric cycle period. To determine the effects of LP and VD neuron removal on pyloric activity independent of these period alterations, we 1) altered network period by current injection into a pyloric pacemaker neuron, 2) hyperpolarized the LP or VD neuron to functionally remove each from the network, and 3) plotted various measures of pyloric neuron activity against period with and without the LP or VD neuron. In normal physiological saline, in many (or most) cases removing either neuron had surprisingly little effect on the activity of its postsynaptic partners, which suggests that under these conditions these neurons play a relatively small role in determining pyloric activity. In the cases in which removal did alter postsynaptic activity, the effects were inconsistent across preparations, which suggests that either 1) despite producing very similar neural outputs, pyloric networks from different animals have different cellular and synaptic properties or 2) some synapses contribute to network activity only under certain modulatory conditions, and the 'baseline' level of modulatory influence the network receives from higher centers varies from animal to animal.'>7Neuroscience Program, Ohio University, Athens, OH, USA."Weaver, A. L. Hooper, S. L."0 0022-3077 Journal articleJ Neurophysiollehttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12801895*$Weimann, J.M. Meyrand, P. Marder, E. 19894-Neurons that participate in several behaviors 0)Erber, J. Menzel, R. Pfluger, H. Todt, D.$Neural Mechanisms of Behavior  Stuttgartu Georg Thieme Verlag58*$Weimann, J.M. Mayrand, P. Marder, E. 19904-Neurons that participate in several behaviors @:Weise, K. Krenz, W.-D. Tautz, J. Reichert, H. Mulloney, B.*$Frontiers in Crustacean Neurobiology Basele Birkhauser Verlag7424-430ry xw.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10707309eTazaki, K. Tazaki, Y./\VMultiple motor patterns in the stomatogastric ganglion of the shrimp Penaeus japonicusXRAction Potentials/drug effects/physiology Animal Electrophysiology Evolution Ganglia, Invertebrate/cytology/physiology Heart/innervation Motor Neurons/*physiology *Nerve Net Nervous System/cytology Neurotransmitters/pharmacology Oligopeptides/pharmacology Shrimp/*physiology Stomach/innervation Support, Non-U.S. Gov't Synapses/physiologyZSMotor patterns of the cardiac sac, the gastric and the pyloric network in the stomatogastric nervous system of the shrimp Penaeus japonicus, the most primitive decapod species, were studied. Single neurons can switch from the gastric or the pyloric pattern to the cardiac sac pattern. Some of the pyloric neurons fire with the gastric pattern. All of the gastric neurons fire with the pyloric pattern, unlike those in reptantians. Proctolin activates and modulates the cardiac sac and the pyloric rhythm, and promotes reconfiguration of the networks. Neurons of the three networks have so many interconnections that they construct a multifunctional neural network like those in Cancer. This network may function in different configurations under the appropriate conditions. Several modes of interactions between the networks found in different reptantian species can apply to the penaeidean shrimp. Such interactions are general features of the stomatogastric nervous system in decapods. Phylogenetic differences among the decapod infraorders are seen in the number and orientation of muscles and the innervation pattern of muscles. The multifunctional networks have existed in the most primitive decapod species, and types of configurations of the networks would have evolved to produce a wide range of motor patterns as the foregut structure has become complex.'XRBiological Laboratory, Nara University of Education, Japan. tazakik@nara-edu.ac.jp10707309J Comp Physiol [A] 2000 1862105-18. Thirumalai, V. Marder, E. leColocalized neuropeptides activate a central pattern generator by acting on different circuit targetslAction Potentials/drug effects/physiology Animal Electrophysiology Ganglia, Invertebrate/cytology/drug effects/*physiology Immunohistochemistry In Vitro Invertebrate Hormones/pharmacology Lobsters Nerve Net/drug effects/physiology Neurons/drug effects/*physiology Neuropeptides/*pharmacology Oligopeptides/pharmacology *Periodicity Signal Processing, Computer-Assisted Stimulation, Chemical Support, U.S. Gov't, P.H.S. Tachykinins/pharmacology In the presence of descending modulatory inputs, the stomatogastric ganglion (STG) of the lobster Homarus americanus generates a triphasic motor pattern, the pyloric rhythm. Red pigment-concentrating hormone (RPCH) and Cancer borealis tachykinin-related peptide (CabTRP) are colocalized in a pair of fibers that project into the neuropil of the STG. When the STG was isolated from anterior ganglia modulatory inputs, the lateral pyloric (LP) and pyloric (PY) neurons became silent, whereas the anterior burster (AB) and pyloric dilator (PD) neurons were rhythmically active at a low frequency. Exogenous application of 10(-6) m RPCH activated the LP neuron but not the PY neurons; 10(-6) m CabTRP activated the PY neurons but not the LP neuron. The actions of RPCH on the LP neuron and CabTRP on the PY neurons persisted when the rhythmic drive from the PD and AB neurons was removed, suggesting that the LP and PY neurons are direct targets for RPCH and CabTRP respectively. Coapplication of 10(-6) m RPCH and 10(-6) m CabTRP elicited triphasic motor patterns with phase relationships resembling those in a preparation with modulatory inputs intact. In summary, cotransmitters acting on different network targets act cooperatively to activate a complete central pattern-generating circuit.'haVolen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454-9110, USA.e11880517 J Neurosci 2002225w1874-82.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11880517 http://www.jneurosci.org/cgi/content/full/22/5/1874 http://www.jneurosci.org/cgi/content/abstract/22/5/1874plfhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/18/6/221298151405$Thoby-Brisson, M. Simmers, J.Neuromodulatory inputs maintain expression of a lobster motor pattern- generating network in a modulation-dependent state: evidence from long- term decentralization in vitroajcAfferent Pathways/physiology Animal Axotomy Central Nervous System/*physiology Female Ganglia, Invertebrate/physiology In Vitro Lobsters/*physiology Male Motor Activity/*physiology Nerve Endings/physiology Nerve Net/*physiology Nervous System Physiology Organ Culture Periodicity Pylorus/physiology Stomach/innervation Support, Non-U.S. Gov't Time FactorseNeuromodulatory inputs play a critical role in governing the expression of rhythmic motor output by the pyloric network in the crustacean stomatogastric ganglion (STG). When these inputs are removed by cutting the primarily afferent stomatogastric nerve (stn) to the STG, pyloric neurons rapidly lose their ability to burst spontaneously, and the network falls silent. By using extracellular motor nerve recordings from long-term organotypic preparations of the stomatogastric nervous system of the lobster Jasus lalandii, we are investigating whether modulatory inputs exert long-term regulatory influences on the pyloric network operation in addition to relatively short-term neuromodulation. When decentralized (stn cut), quiescent STGs are maintained in organ culture, pyloric rhythmicity gradually returns within 3-5 d and is similar to, albeit slower than, the triphasic motor pattern expressed when the stn is intact. This recovery of network activity still occurred after photoinactivation of axotomized input terminals in the isolated STG after migration of Lucifer yellow. The recovery does not depend on action potential generation, because it also occurred in STGs maintained in TTX-containing saline after decentralization. Resumption of rhythmicity was also not activity-dependent, because recovery still occurred in STGs that were chronically depolarized with elevated K+ saline or were maintained continuously active with the muscarinic agonist oxotremorine after decentralization. We conclude that the prolonged absence of extraganglionic modulatory inputs to the pyloric network allows expression of an inherent rhythmogenic capability that is normally maintained in a strictly conditional state when these extrinsic influences are present. J Neurosci 19981862212-25|{ dz $Thoby-Brisson, M. Simmers, J.h{Transition to endogenous bursting after long-term decentralization requires De novo transcription in a critical time windowy\UAnimal Dactinomycin/pharmacology Electrophysiology Ganglia, Invertebrate/physiology Gene Expression/drug effects/physiology Lobsters Movement/physiology Neurons/*physiology Nucleic Acid Synthesis Inhibitors/pharmacology *Periodicity RNA/biosynthesis Stomach/innervation Support, Non-U.S. Gov't Time Factors Transcription, Genetic/*physiologyh"Rhythmic motor pattern generation by the pyloric network in the lobster stomatogastric ganglion (STG) requires neuromodulatory inputs from adjacent ganglia. However, although suppression of these inputs by cutting the stomatogastric nerve (stn) causes the pyloric network to fall silent, network output similar to that expressed when the stn is intact returns after 3-4 days in organ culture. Intracellular recordings from identified pyloric dilator (PD) neurons indicate that the fundamental change underlying rhythm recovery resides with the intrinsic excitability of pyloric neurons themselves, since the prolonged absence of extrinsic modulatory inputs allows the expression of an endogenous oscillatory capability that is maintained in a strictly conditional state when these inputs are present. To examine whether gene transcription was involved in this change in neuronal behavior, we performed in vitro experiments in which the STG was exposed to the RNA-synthesis inhibitor actinomycin D (ACD). ACD (50 microM) incubation at the time of decentralization prevented subsequent reacquisition of PD neuron bursting, but the inhibitor was much less effective when applied at later postdecentralization times, suggesting that the recovery process arises from new protein synthesis triggered when modulatory inputs are first removed. Moreover, in the nondecentralized STG, trans-synaptic modulatory instruction may sustain the conditional pyloric network phenotype by continuously regulating expression of genes responsible for intrinsic neuronal rhythmogenesis.'Laboratoire de Neurobiologie des Reseaux, Universite Bordeaux I and Centre National de la Recherche Scientifique- Unite Mixte de Recherche 5816, 33405 Talence, France.10899233http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=10899233 http://www.jn.physiology.org/cgi/content/full/84/1/596 http://www.jn.physiology.org/cgi/content/abstract/84/1/596J Neurophysiol 2000841 596-9.12466420886e 2002 DecmLong-term neuromodulatory regulation of a motor pattern-generating network: maintenance of synaptic efficacy and oscillatory properties2942-53IRhythm generation by the pyloric motor network in the stomatogastric ganglion (STG) of the spiny lobster requires permissive neuromodulatory inputs from other central ganglia. When these inputs to the STG are suppressed by cutting the single, mainly afferent stomatogastric nerve (stn), pyloric neurons cease to burst and the network falls silent. However, as shown previously, if such a decentralized quiescent ganglion is maintained in organ culture, pyloric network rhythmicity returns after 3-4 days and, although slower, is similar to the motor pattern expressed when the stn is intact. Here we use current- and voltage-clamp, primarily of identified pyloric dilator (PD) neurons, to investigate changes in synaptic and cellular properties that underlie this transition in network behavior. Although the efficacy of chemical synapses between pyloric neurons decreases significantly (by 8Some experiments on learning stable network oscillations81International Joint Conference on Neural Networks  San DiegoeZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11205354fNHVarona, P. Torres, J. J. Abarbanel, H. D. Rabinovich, M. I. Elson, R. C.hbDynamics of two electrically coupled chaotic neurons: experimental observations and model analysisxqAnimal Lobsters *Models, Neurological Neurons/*physiology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S.yB;Conductance-based models of neurons from the lobster stomatogastric ganglion (STG) have been developed to understand the observed chaotic behavior of individual STG neurons. These models identify an additional slow dynamical process calcium exchange and storage in the endoplasmic reticulum as a biologically plausible source for the observed chaos in the oscillations of these cells. In this paper we test these ideas further by exploring the dynamical behavior when two model neurons are coupled by electrical or gap junction connections. We compare in detail the model results to the laboratory measurements of electrically- coupled neurons that we reported earlier. The experiments on the biological neurons varied the strength of the effective coupling by applying a parallel, artificial synapse, which changed both the magnitude and polar-of the conductance between the neurons. We observed a sequence of bifarctions that took the neurons from strongly synchronized in-phase behavior. through uncorrelated chaotic oscillations to strongly synchronized and now regular out-of-phase behavior. The model calculations reproduce these observations quantitatively, indicating that slow subcellular processes could account for the mechanisms involved in the synchronization and regularization of the otherwise individual chaotic activities.'yInstitute for Nonlinear Science, University of California, San Diego, La Jolla 92093-0402, USA. pvarona@lyapunov.ucsd.edu11205354 Biol Cybern 200184291-101.ZShttp://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=11665777 LFVarona, P. Torres, J. J. Huerta, R. Abarbanel, H. D. Rabinovich, M. I.<5Regularization mechanisms of spiking-bursting neuronss An essential question raised after the observation of highly variable bursting activity in individual neurons of Central Pattern Generators (CPGs) is how an assembly of such cells can cooperatively act to produce regular signals to motor systems. It is well known that some neurons in the lobster stomatogastric ganglion have a highly irregular spiking-bursting behavior when they are synaptically isolated from any connection in the CPG. Experimental recordings show that periodic stimuli on a single neuron can regulate its firing activity. Other evidence demonstrates that specific chemical and/or electrical synapses among neurons also induce the regularization of the rhythms. In this paper we present a modeling study in which a slow subcellular dynamics, the exchange of calcium between an intracellular store and the cytoplasm, is responsible for the origin and control of the irregular spiking-bursting activity. We show this in simulations of single cells under periodic driving and in minimal networks where the cooperative activity can induce regularization. While often neglected in the description of realistic neuron models, subcellular processes with slow dynamics may play an important role in information processing and short- term memory of spiking-bursting neurons.'d^Institute for Nonlinear Science, UCSD, La Jolla, CA 92093-0402, USA. pvarona@lyapunov.ucsd.edu11665777 Neural Netws 200114 6-7n865-75.eVedel, J.-P. Moulins, M. 1977voFunctional properties of interganglionic motor neurons in the stomatogastric nervous system of the rock lobsterHJ Comp Physiol 118307-325v.(Wales, W. Macmillan, D.L. Laverack, M.S. 1976TMandibular movements and their control in Homarus gammarus. I. Mandible morphology*<J Comp Physiol 106h177-191g76233317$Warshaw, H. S. Hartline, D. K.`YSimulation of network activity in stomatogastric ganglion of the spiny lobster, Panulirus*Action Potentials Adaptation, Physiological Animal Evoked Potentials Ganglia/*physiology Lobsters *Models, Neurological Neural Inhibition Neural Pathways Neurons/physiology Refractory Period, Neurologic Support, U.S. Gov't, P.H.S. Synapses/physiologyWe have compared experimental and model studies on the rhythmic activity of the lobster stomatogastric ganglion. Both the pyloric and gastric mill systems were simulated using a physiologically based network model. In the pyloric simulation the known synaptic connectivity of the 3 principal cell types in the pyloric rhythm was found to be sufficient to produce the correct sequence of cyclic bursting activity over a substantial range of parameter values, even though we did not simulate the known endogenous oscillatory driver potential of one of the cell types. It is not yet known whether the synaptic inhibition in the real system is in the right range to cause cyclic bursting in the absence of the driver potential, but the synaptic connectivity does appear to reinforce the cyclic pattern. Simulations were also done with alternative connectivity schemes to determine which synapses appear essential to generate the correct bursting sequence (in the absence of endogenous bursting activity). Other, more complex, systems simulated were: (1) all 5 cell groups of the pyloric system, and (2) the cells responsible for movement of the lateral teeth in the gastric mill. In both cases good qualitative agreement was achieved between model and real systems.m Brain Ress 1976 110 2r 259-72( zb90231436*#Turrigiano, G. G. Selverston, A. I.oZTA cholecystokinin-like hormone activates a feeding-related neural circuit in lobsterAnimal Cholecystokinin/antagonists & inhibitors/pharmacology/*physiology Digestive Physiology Digestive System/drug effects/innervation/physiology Eating/*physiology Hemolymph/metabolism Lobsters/*physiology Neurons/physiology Proglumide/pharmacology Support, U.S. Gov't, P.H.S.The peptide hormone cholecystokinin (CCK) contributes to the production of feeding-related behaviour in mammals, but the mechanism by which it exerts its effects remains unclear. The gastric mill neural circuit of lobster is an experimentally accessible model system for studying the hormonal control of feeding-related behaviour. Composed of 11 identified neurons, this circuit produces rhythmic movement of teeth within the stomach. We have previously shown that the gastric mill motor pattern can be modulated by a cholecystokinin-like peptide in vitro. We report here that (1) after feeding, levels of CCK-like peptide in haemolymph increase with the activation of the gastric mill, (2) injections of CCK activate the gastric mill, and (3) a specific CCK antagonist inhibits feeding-induced gastric mill activity. This neatly demonstrates a casual link between in vivo release of a peptide hormone and activation of a neural circuit. Nature 1990 344 6269 866-8(!Turrigiano, G.G. Selverston, A.I. 1990Stomatogastric ganglion: Neuromodulatory role of a cholecystokinin-like peptide and a recurrent back propagation model of the gastric system @:Weise, K. Krenz, W.-D. Tautz, J. Reichert, H. Mulloney, B.*$Frontiers in Crustacean Neurobiology Basely Birkhauser Verlaga407-416/91236875*#Turrigiano, G. G. Selverston, A. I.Distribution of cholecystokinin-like immunoreactivity within the stomatogastric nervous systems of four species of decapod crustaceaAnimal Cholecystokinin/immunology/*metabolism Comparative Study Crabs/metabolism Cross Reactions Crustacea/*metabolism Esophagus/innervation Ganglia/cytology Hemolymph/immunology/metabolism Immunohistochemistry Lobsters/metabolism Nervous System/immunology/*metabolism Peptides/immunology/physiology Radioimmunoassay Species Specificity Staining Stomach/*innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.The distribution of cholecystokinin-like immunoreactivity was studied in the stomatogastric nervous systems, pericardial organs, and haemolymph of four species of decapod crustacea, by using immunocytochemical and radioimmunoassay techniques. Whereas cholecystokinin-like immunoreactivity was found within the stomatogastric nervous systems of all four species, its distribution in each is unique. Two species (Panulirus interruptus and Homarus americanus) have cholecystokinin-like immunoreactivity within fibers and neuropil of the stomatogastric ganglion (STG); two other species (Cancer antenarius and Procambarus clarkii) do not. Further, the cholecystokinin-like immunoreactivity within the STGs of Panulirus and Homarus arise from distinct structures; from a projection of anterior ganglia in Panulirus, and from somata within the posterior motor nerves in Homarus. The staining in the other ganglia of the stomatogastric nervous system also shows some interspecies variability, although it appears to be more highly conserved than staining within the STG. These differences in staining were confirmed by measuring the amount of CCK- like peptide present in tissue extracts of ganglia by radioimmunoassay. In contrast to the variable staining within the STG, all four species have cholecystokinin-like immunoreactivity within the neurosecretory pericardial organs and thoracic segmental nerves. This cholecystokinin- like immunoreactivity is contained within fibers and within varicosities that coat the surface of these structures. The location of this staining and the presence of detectible levels of CCK-like peptide in the haemolymph suggests that CCK-like peptides in decapod crustacea may be utilized as neurohormones. J Comp Neurol 1991 3051 164-76&Turrigiano, G.G. Heinzel, H. G. 1992>8Behavioral correlates of stomatogastric network function BDynamic Biological Networks: The Stomatogastric Nervous System  Cambridge, MA  MIT PressC197-220r93353236"Turrigiano, G. G. Marder, E.VPModulation of identified stomatogastric ganglion neurons in primary cell culture Action Potentials/drug effects/physiology Animal Cell Survival/drug effects Cells, Cultured Dopamine/pharmacology Electrophysiology Ganglia/cytology/*physiology Lobsters/*physiology Membrane Potentials/drug effects Neurites/drug effects Neurons/drug effects/*physiology Neurotransmitters/pharmacology Octopamine/pharmacology Oligopeptides/pharmacology Pilocarpine/pharmacology Serotonin/pharmacology Stomach/innervation Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. Tetraethylammonium Compounds/pharmacology1. We studied the properties of identified stomatogastric ganglion (STG) neurons grown in complete isolation in primary cell culture. 2. STG neurons isolated with a short piece of primary neurite adhered to the culture dishes and extended neurites. Outgrowth was apparent within several hours, and continued for or = 5 days. 3. After 1 day in culture, most STG neurons were not capable of producing action potentials or oscillations. After 3-5 days in culture, most STG neurons regained the ability to fire action potentials, and some became endogenous bursters. Neurons in culture 3-5 days possessed many of the physiological properties of STG neurons in situ, including postinhibitory rebound, a hyperpolarization-activated depolarizing voltage sag, and the ability to burst in the presence of the potassium channel blocker tetraethyl-ammonium. 4. Identified cultured neurons responded appropriately to a variety of neuromodulators, including the monoamines dopamine and octopamine, the muscarinic agonist pilocarpine, and the peptide proctolin. These data suggest that the maintenance of receptor expression in fully differentiated STG neurons is not affected by isolation from all synaptic and modulatory influences. 5. In contrast to the other modulators tested, the effects of serotonin on cultured neurons differed from those reported in situ. Two cell types that are reported to be hyperpolarized by serotonin in situ, the lateral pyloric and pyloric neurons, were depolarized by serotonin in culture. J Neurophysiol 1993696n 1993-2002   :95053639&Zhang, B. Harris-Warrick, R. M.ijcMultiple receptors mediate the modulatory effects of serotonergic neurons in a small neural networkt>7Animal Crabs Electrophysiology Nerve Net/*physiology Neurons/drug effects/*physiology Pylorus/innervation Receptors, Serotonin/*physiology Serotonin/*physiology Serotonin Agonists/pharmacology Serotonin Antagonists/pharmacology Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S.u,%The gastropyloric receptor (GPR) cells are a set of cholinergic/serotonergic mechanosensory neurons that modulate the activity of neural networks in the crab stomatogastric ganglion (STG). Stimulation of these cells evokes a variety of slow modulatory responses in different STG neurons that are mimicked by exogenously applied serotonin (5-HT); these responses include tonic inhibition, tonic excitation and induction of rhythmic bursting. We used pharmacological agonists and antagonists to show that these three classes of modulatory response in the STG neurons are mediated by distinct 5-HT receptor subtypes. GPR stimulation or application of 5-HT or 2-me-5HT (a vertebrate 5-HT3 agonist) inhibited the pyloric constrictor (PY) neurons; these actions were selectively antagonized by gramine. GPR stimulation or application of 5-HT induced rhythmic bursting in the electrically coupled anterior burster (AB) and pyloric dilator (PD) neurons; these effects were antagonized by the 5-HT1c/2 antagonist cinanserin and by atropine at concentrations that do not block muscarinic cholinergic receptors in the crab STG. The 5-HT agonists 5-CT (5-HT1) and alpha-me-5HT (5-HT2) also induced AB/PD bursting, which was blocked by cinanserin, but not by atropine. GPR stimulation or application of 5-HT and 5-CT evoked tonic excitation of the lateral pyloric (LP) neuron. These effects were blocked by cinanserin. Several other 5-HT agonists and nearly all the vertebrate 5- HT antagonists we tested had little or no effect on the crab pyloric 5- HT receptors. These results provide further evidence that the modulatory sensory GPR neuron uses serotonin to evoke multiple modulatory responses via multiple 5-HT receptors. However, the 5-HT receptors in the crab STG neurons are not pharmacologically similar to vertebrate 5-HT receptors. J Exp Biol 1994 190 55-7796150907&Zhang, B. Harris-Warrick, R. M.rCalcium-dependent plateau potentials in a crab stomatogastric ganglion motor neuron. I. Calcium current and its modulation by serotoninC^XAnimal Barium/physiology Calcium/*physiology Crabs/*physiology Ganglia, Invertebrate/cytology/*physiology Ion Channels/physiology Kinetics Membrane Potentials/physiology Motor Neurons/*physiology Patch-Clamp Techniques Serotonin/physiology Stomach/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, Non-P.H.S. Support, U.S. Gov't, P.H.S. | v1. Using current- and voltage-clamp techniques, we examined the biophysical properties of a voltage-dependent Ca2+ current and its physiological role in plateau potential generation in the dorsal gastric (DG) motor neuron of the stomatogastric ganglion in the crab, Cancer borealis. 2. Stimulation of one of a set of identified serotonergic/cholinergic mechanosensory cells, the gastropyloric receptor (GPR) cells, induced plateau potentials in DG. A brief pressure application of serotonin (5-HT) closely mimicked the effect of the GPR cells. The 5-HT-evoked plateau in DG was not blocked by the sodium channel blocker, tetrodotoxin (TTX), or a combination of TTX with potassium channel blockers, including tetraethylammonium (TEA) and 4-aminopyridine (4-AP), and the Ih blocker, CsCl. The 5-HT-evoked plateau was eliminated by the Ca2+ channel blockers Co2+ and Cd2+, suggesting that Ca2+ entry is essential for plateau potentials in DG. During the plateau, we observed a 30% decrease in input resistance. 3. When sodium and potassium currents were blocked pharmacologically, injection of suprathreshold depolarizing current evoked all-or-none plateau-like responses lasting several seconds, even in the absence of 5-HT. This response was blocked by Ca2+ channel blockers, further supporting a role for Ca2+ in plateau generation. 5-HT significantly prolonged the duration of this plateau. 4. We isolated a voltage- dependent Ca2+ current in voltage-clamped DG neurons. This current was analyzed with the use of either Ca2+ or Ba2+ as the charge carrier after other currents had been maximally blocked with extracellular TTX, TEA, 4-AP, and CsCl and intracellular loading with Cs+ and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). The Ca2+ current was detectable at -45 mV, peaked at -15 mV, and was estimated to reverse at +45 mV. Co2+ and Cd2+ effectively blocked the Ca2+ current. 5. The voltage dependence of activation of the Ca2+ current was quantantitively analyzed by fitting the voltage-conductance relation with a third power Boltzmann relation. The maximum conductance (gA), half-activation voltage (VA) for individual gating steps, and the slope steepness (k) were 0.19 +/- 0.02 (SE) microS, -36.5 +/- 2.0 mV, and 4.4 +/- 1.4 mV/e-fold, respectively. 6. 5-HT significantly potentiated the gA by approximately 42% without affecting VA and k. 7. We conclude from our current- and voltage-clamp results that a voltage- dependent Ca2+ current plays an important role in generating plateau potentials in the DG neuron. Enhancement of the voltage-dependent Ca2+ current by 5-HT is one of the mechanisms for 5-HT-evoked plateau potentials.J Neurophysiol 1995745h1929-37r 091154872,%Weimann, J. M. Meyrand, P. Marder, E.yNeurons that form multiple pattern generators: identification and multiple activity patterns of gastric/pyloric neurons in the crab stomatogastric systemt,&Action Potentials/physiology Animal Crabs/*physiology Electrophysiology Membrane Potentials/physiology Motor Neurons/physiology Muscles/physiology Neurons/*physiology Pylorus/innervation/physiology Reaction Time Stomach/innervation/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.1. The stomatogastric ganglion (STG) of decapod crustaceans has been characterized by its production of two motor patterns, the gastric mill rhythm and the pyloric rhythm. The period of the gastric rhythm is typically 5-10 s, whereas the period of the pyloric rhythm is approximately 1 s. 2. In the STG of the crab, Cancer borealis, we find routinely that many motor neurons are active in time with both the pyloric and gastric rhythms. We rigorously identified the motor neurons according to the muscles they innervate. Some neurons usually classified as members of the pyloric network can be active in time with the gastric rhythm. All of the gastric motor neurons except the dorsal gastric (DG) neuron can generate pyloric-timed firing patterns. 3. Two motor neurons innervate muscles found in several different regions of the stomach. The inferior cardiac (IC) neuron, usually considered part of the pyloric network, innervates cardiac sac, gastric mill, and pyloric muscles. The lateral posterior gastric (LPG) neurons innervate muscles of both the gastric mill and the pyloric chamber. 4. These data show that the gastric and pyloric networks in the crab are not separate groups of neurons that independently generate two different rhythmic behaviors. Rather, these neurons together provide a synaptically connected pool of neurons from which many different pattern-generating circuits can be assembled, under different physiological conditions.PJ Neurophysiol 1991651h 111-2294014868:4Weimann, J. M. Marder, E. Evans, B. Calabrese, R. L.The effects of SDRNFLRFamide and TNRNFLRFamide on the motor patterns of the stomatogastric ganglion of the crab Cancer borealistLFAmino Acid Sequence Animal Crabs/*physiology Digestive Physiology Digestive System/drug effects/innervation/physiology Evoked Potentials/drug effects Ganglia, Invertebrate/drug effects/physiology Male Molecular Sequence Data Neuropeptides/chemistry/*pharmacology Periodicity Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.HATNRNFLRFamide was isolated and sequenced from the stomatogastric nervous system of the crab Cancer borealis by reverse-phase high performance liquid chromatography followed by automated Edman degradation. An SDRNFLRFamide-like peptide that exactly co-migrated with SDRNFLRFamide was also observed. The effects of TNRNFLRFamide and SDRNFLRFamide on the gastric and pyloric rhythms of the stomatogastric nervous system of the crab Cancer borealis were studied. Both peptides activated pyloric rhythms in quiescent preparations in a dose-dependent manner with a threshold between 10(-11) and 10(-10) mol l-1. Both peptides increased the pyloric rhythm frequency of preparations showing moderate activity levels and had relatively little effect on preparations that showed strong pyloric rhythms prior to peptide application. Both peptides evoked gastric mill activity in preparations without existing gastric rhythms. The activation of the gastric rhythm is associated with activation of oscillatory properties in the dorsal gastric neurone. The induction of gastric rhythms by these peptides was accompanied by switches from pyloric-timed activity to gastric-timed activity by several stomatogastric ganglion neurones. Application of these peptides provides direct experimental control of circuit modification in the stomatogastric nervous system.h J Exp Biol 1993 181i 1-2695153278 Weimann, J. M. Marder, E.eNGSwitching neurons are integral members of multiple oscillatory networksaAnimal Crabs/*physiology Ganglia, Invertebrate/physiology Membrane Potentials Neurons/*physiology Stomach/innervation/physiology Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.B;BACKGROUND: The stomatogastric ganglion of the crab Cancer borealis contains the neurons that generate several different behaviors, such as the fast pyloric rhythm and the slower gastric-mill rhythm. It has previously been shown that many stomatogastric ganglion neurons can switch between pyloric- and gastric-timed activity. However, the question remained whether these neurons really are integral members of several central-pattern-generating networks, or just passive followers that only change their activity patterns in response to a switch determined by other neurons. RESULTS: To address this question, we perturbed the activity of the 'pyloric' ventricular dilator neuron and the 'gastric' lateral gastric neuron during ongoing pyloric and gastric rhythms. In the absence of ongoing gastric rhythms, these neurons can fire in pyloric time, and perturbing them can reset the pyloric rhythm. During robust gastric activity, the lateral gastric and ventricular dilator neurons can fire in gastric time, and perturbing them can reset the gastric rhythm. CONCLUSIONS: When stomatogastric ganglion neurons change their firing patterns, they also function as part of the circuitry that generates the new rhythm with which they are firing, demonstrating that individual neurons can be used as part of multiple pattern-generating circuits.  Curr Biolo 19944s10896-902bb[Weimann, J. M. Skiebe, P. Heinzel, H. G. Soto, C. Kopell, N. Jorge-Rivera, J. C. Marder, E.r 1997rlModulation of oscillator interactions in the crab stomatogastric ganglion by crustacean cardioactive peptide J Neurosci1751748-60\97184221Action Potentials/drug effects Animal Calcitonin/administration & dosage/*pharmacology/physiology Crabs/*physiology Dose-Response Relationship, Drug Ganglia, Invertebrate/*drug effects/physiology Gastrointestinal Motility/*drug effects Motor Neurons/drug effects/physiology Neuromuscular Junction/drug effects/physiology Peptide Fragments/administration & dosage/*pharmacology/physiology Periodicity Pylorus/*innervation Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S.The modulation of the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis, by crustacean cardioactive peptide (CCAP) is described. CCAP activated pyloric rhythms in most silent preparations, and altered the phase relationships of pyloric motor neuron firing in all preparations. In CCAP, the pyloric rhythms were characterized by long lateral pyloric (LP) neuron bursts of action potentials. The threshold for CCAP action was approximately 10(-10) M, with increasing effects at higher CCAP concentrations. The changes in motor pattern evoked by CCAP produced significant changes in LP-innervated muscle movement. These movements were additionally potentiated by CCAP applications to isolated nerve-muscle preparations. Thus, enhanced motor neuron firing and increase of the gain of the neuromuscular junctions are likely to operate coordinately in response to hormonally released CCAP. High CCAP concentrations sometimes resulted in modification of the normal 1:1 alternation between the pyloric dilator (PD) and LP neurons to patterns of 2:1, 3:1, or 4:1 alternation. CCAP seems to activate slow intrinsic oscillations in the LP neuron, as well as enhance faster oscillations in the pacemaker group of PD/anterior burster (AB) neurons. Simulations of fast and slow oscillators with reciprocal inhibitory coupling suggest mechanisms that could account for the mode switch from 1:1 alternation to multiple PD bursts alternating with one LP neuron burst.ilfhttp://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.jneurosci.org/cgi/content/full/17/5/1748 b12612050894 2003 AprztKChIP1 and frequenin modify shal-evoked potassium currents in pyloric neurons in the lobster stomatogastric ganglion 1902-9The transient potassium current (I(A)) plays an important role in shaping the firing properties of pyloric neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. The shal gene encodes I(A) in pyloric neurons. However, when we over-expressed the lobster Shal protein by shal RNA injection into the pyloric dilator (PD) neuron, the increased I(A) had somewhat different properties from the endogenous I(A). The recently cloned K-channel interacting proteins (KChIPs) can modify vertebrate Kv4 channels in cloned cell lines. When we co-expressed hKChIP1 with lobster shal in Xenopus oocytes or lobster PD neurons, they produced A-currents resembling the endogenous I(A) in PD neurons; compared with currents evoked by shal alone, their voltage for half inactivation was depolarized, their kinetics of inactivation were slowed, and their