Abstract
The crustacean stomatogastric nervous system has become one of the premier preparations used for the study of the mechanisms underlying the generation of rhythmic motor patterns. The stomatogastric ganglion (STG) contains about thirty neurons, most of which are motor neurons that innervate more than forty sets of striated muscles that move the animal's stomach. This chapter argues that work on the STG, in addition to providing basic insights into the mechanisms underlying generation of rhythms in the nervous system, has contributed to our understanding of a number of problems in neuroscience. These findings include the following: Individual neurons and networks are modulated by many substances to alter intrinsic neuronal excitability and synaptic strength, thus reconfiguring neuronal networks. All of the neurons and synapses within a circuit are likely targets for neuromodulation. There are a variety of longterm compensatory mechanisms that tend to maintain stable function after the neuromodulatory inputs are removed. Each identified neuron type in the STG may have a characteristic set of correlations in the expression of its ion channel genes.