Summary
In crayfish,Pacifastacus leniusculus, abdominal ganglia that can generate the motor pattern normally associated with swimmeret beating continue to do so when the number of connected ganglia is reduced from six to two. The period and phase of the rhythm produced by these shortened chains of ganglia are the same as those produced by the full abdominal nerve cord. These results demonstrate that interactions between any two neighboring ganglia suffice to establish the metachronal phase-lag characteristic of the swimmeret rhythm.
Several kinds of interganglionic interneurons that are part of the swimmeret system originate in each abdominal ganglion. These premotor interneurons receive synaptic input in the ganglion of origin and project to other ganglia. Axons from interganglionic neurons also terminate in each ganglion, and some of these terminals receive PSPs from the swimmeret pattern generators in the ganglion where they terminate. Currents injected into these interneurons and axon terminals can reset the swimmeret rhythm. These results demonstrate that premotor interganglionic interneurons exist that have the properties required to coordinate adjacent ganglia. The structures and physiological properties of these interneurons are described and discussed in the context of Stein's model of intersegmental coordination in the swimmeret system.
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References
Bradbury AG, Mulloney B (1982) Proctolin activates and octopamine inhibits swimmeret beating. Neurosci Abstr 8:213.5
Calabrese RL (1980) Control of multiple impulse-initiating sites in a leech interneuron. J Neurophysiol 44:878–896
Friesen WO, Poon M, Stent GS (1978) Neuronal control of swimming in the medicinal leech. IV. Identification of a network of oscillatory interneurons. J Exp Biol 75:25–43
Heitler W (1980) Neural mechanisms of central pattern generation in the crayfish swimmeret system. Adv Physiol Sci 23:369–383
Hughes GM, Wiersma CAG (1960) The co-ordination of swimmeret movements in the crayfish,Procambarus clarkii. J Exp Biol 37:657–670
Ikeda K, Wiersma CAG (1964) Autogenic rhythmicity in the abdominal ganglia of the crayfish: the control of swimmeret movements. Comp Biochem Physiol 12:107–115
Jacobs GA (1980) Effects of sensory feedback on the central pattern generator in the crayfish swimmeret system. MA thesis, University of California, Davis
Kennedy D, Mellon DF (1964) Synaptic activation and receptive fields in crayfish interneurons. Comp Biochem Physiol 13:275–300
Macmillan DL, Altman JS, Kien J (1983) Intersegmental coordination in the crayfish swimmeret system reconsidered. J Exp Zool 228:157–162
Mulloney B, Selverston AI (1974) Organization of the stomatogastric ganglion of the spiny lobster. I. Neurons driving the lateral teeth. J Comp Physiol 91:1–32
Paul DH, Mulloney B (1985a) A nonspiking local interneuron in the motor pattern generator for the crayfish swimmeret. J Neurophysiol 54:28–39
Paul DH, Mulloney B (1985b) Local interneurons in the swimmeret system of crayfish. J Comp Physiol A 156:489–502
Pearson KG (1979) Local neurons and local interactions in the nervous systems of invertebrates. In: Schmitt FO, Worden FG (eds) The neurosciences fourth study program. M.I.T. Press, Cambridge, pp 145–160
Rakic P (1975) Local circuit neurons. Neurosci Res Prog Bull 13: (3)
Reichert H, Rowell CHF (1985) Integration of non-phase-locked exteroceptive information in the control of rhythmic flight in the locust. J Neurophysiol 53:1201–1218
Rowell CHF, Reichert H (1985) Compensatory steering in locusts: the integration of non-phase-locked input with a rhythmic motor output. In: Gewecke M, Wendler G (eds) Insect locomotion. Parey, Berlin
Sigvardt KA, Hagiwara G, Wine JJ (1982) Mechanosensory integration in the crayfish abdominal nervous system: Structural and physiological differences between interneurons with single and multiple spike-initiating sites. J Comp Physiol 148:143–157
Skinner K (1985a) The structure of the fourth abdominal ganglion of the crayfish,Procambarus clarkii. I. Tracts in the ganglionic core. J Comp Neurol 234:168–181
Skinner K (1985b) The structure of the fourth abdominal ganglion of the crayfish,Procambarus clarkii. II. Synaptic neuropils. J Comp Neurol 234:182–191
Stein PSG (1971) Intersegmental coordination of swimmeret motoneuron activity in crayfish. J Neurophysiol 34:310–318
Stein PSG (1974) Neural control of interappendage phase during locomotion. Am Zool 14:1003–1016
Stewart WW (1978) Functional connections between cells as revealed by dye coupling with a highly fluorescent naphthalimide tracer. Cell 14:741–759
Wiersma CAG, Hughes GM (1961) On the functional anatomy of neuronal units in the abdominal cord of the crayfish,Procambarus clarkii. J Comp Neurol 116:209–228
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Paul, D.H., Mulloney, B. Intersegmental coordination of swimmeret rhythms in isolated nerve cords of crayfish. J. Comp. Physiol. 158, 215–224 (1986). https://doi.org/10.1007/BF01338564
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DOI: https://doi.org/10.1007/BF01338564