Neural mechanisms for the production of cyclic motor patterns

A new dye-sensitized photoinactivation technique was used to remove cells from small networks so as to allow the study of central pattern generation in the lobster stomatogastric ganglion is described. This ganglion, containing only 30 neurons, produces two cyclic patterns. The pyloric and the gastric, when completely deafferented. Both patterns are found to utilize both cellular properties and synaptic network interactions to generate their respective rhythms. Reciprocal inhibition, synaptically activated membrane potential oscillations, and an endogenously bursting cell are shown to be responsible for generating the pyloric rhythm. A hypothesis is suggested, based on a simplified gastric circuit, to explain the generation of the four-phase gastric rhythm. Several preliminary tests of this hypothesis are also discussed.