Kenji Doya, Mary Boyle, Allen Selverston
A computer model of the musculoskeletal system of the lobster gastric mill was constructed in order to provide a behavioral in(cid:173) terpretation of the rhythmic patterns obtained from isolated stom(cid:173) atogastric ganglion. The model was based on Hill's muscle model and quasi-static approximation of the skeletal dynamics and could simulate the change of chewing patterns by the effect of neuromod(cid:173) ulators.
1 THE STOMATOGASTRIC NERVOUS SYSTEM
The crustacean stomatogastric ganglion (STG) is a circuit of 30 neurons that con(cid:173) trols rhythmic movement of the foregut. It is one of the best elucidated neural circuits. All the neurons and the synaptic connections between them are identi(cid:173) fied and the effects of neuromodulators on the oscillation patterns and neuronal characteristics have been extensively studied (Selverston and Moulins 1987, H arris(cid:173) Warrick et al. 1992). However, STG's function as a controller of ingestive behavior is not fully understood in part because of our poor understanding of the controlled object: the musculoskeletal dynamics of the foregut. We constructed a mathemat(cid:173) ical model of the gastric mill, three teeth in the stomach, in order to predict motor patterns from the neural oscillation patterns which are recorded from the isolated ganglion.
The animal we used was the Californian spiny lobster (Panulirus interruptus), which