Neural circuitry underlying oscillatory motor output.

1. 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.