Invertebrate Pattern Generation: Overview

Detailed Description

Central pattern generators (CPGs) are networks of neurons in the central nervous system (CNS) that produce patterned activity, usually as coherent oscillations, in the absence of external timing cues. CPGs provide timing input to motor neurons whose discharge dictates movements of muscles that control rhythmic behavior such as respiration or locomotion (Marder and Calabrese 1996). The long-held debate between scientists who believed half a century ago that rhythmic motor activity is generated by reflex chains and those who held the more radical view of centrally generated rhythms was resolved conclusively, in favor of the latter group, by demonstrating that neural networks generating rhythmic motor activity can do so in the isolated nervous system, in the absence of the body and therefore sensory feedback. In the early 1960s, these “fictive” motor patterns were first demonstrated to govern rhythmic activation in two invertebrate model systems: the movement of...