The Role of Electrical Coupling in Rhythm Generation in Small Networks

Generation of rhythmic activity in numerous systems has been shown to depend on electrical coupling. Small networks provide a strong advantage for studying electrical coupling because, thanks to the accessibility and limited number of neurons, their role in network activity and even behavior can be determined accurately and rigorously. We discuss the known role of electrical coupling in the generation of rhythmic activity, describing experimental and theoretical work. Interestingly, a large body of work indicates that electrical coupling-based rhythmogenesis may be prevalent during early development. The best known effect of electrical coupling in rhythmic networks is the regulation of synchronization and pattern generation, which we describe in the context of electrical coupling, both rectifying and nonrectifying, and its interactions with chemical synaptic coupling. Finally, we discuss the important issue of neuromodulation of gap junctions and its role in regulation of pattern generation and behavior.