NEURAL CIRCUITS FOR GENERATING RHYTHMIC MOVEMENTS

Abstract

This chapter presents an overview on the neural circuits for generating rhythmic movements. The rhythmic movements of vertebrate and invertebrate animals are usually generated by neural elements wholly within the central nervous system. Models that explain how neurons of the central nervous system can produce rhythmic activity fall into two general classes: (1) endogenous polarization rhythms that depend on special oscillatory properties of individual neurons, and (2) network oscillations that depend on oscillatory properties devolving from the connections linking a set of neurons with endogenously stable polarization levels. The pattern of motor neuron activity in rhythmic movements of vertebrates is not necessarily more complex than the corresponding pattern in analogous movements of invertebrates. Therefore, the greater number of neurons in the central nervous system of vertebrates does not necessarily imply a greater complexity of the central oscillators generating their rhythmic movements. The current list of fundamentally different and theoretically plausible types of neuronal oscillators is not only quite short but also of long standing. Thus, on these grounds it is reasonable to expect that the circuits discussed in the chapter are of general applicability to the generation of rhythmic movements in the whole animal kingdom.