Central pattern generator mediating swimming in Tritonia. I. Identification and synaptic interactions.

Publisher Website
Google Scholar
Abstract
The swimming behavior of the marine mollusk, T. diomedea, consists of a series of 2-20 alternating dorsal and ventral flexions. Three populations of cerebral interneurons that participate in the generation of the motor program underlying the swim behavior were identified. The 3 interneuron populations are termed C2, dorsal swim interneurons (DSI) and ventral swim interneurons (VSI). The involvement of 2 of these populations, C2 and DSI, in the generation of the swim motor program was established by phase-shift experiments. The role of the VSI in pattern generation is inferred from its firing pattern during a swim sequence and from its synaptic interactions with the C2 and DSI. During a swim, the C2 and DSI fire coactive bursts, which are correlated with the dorsal flexion of the swim behavior. The VSI fire a predominant burst in antiphase with the C2 and DSI and are thus active during the ventral flexion of the behavior. The functional synaptic interactions among the interneurons were determined by pairwise intracellular recordings in quiescent preparations. Evidence is provided that these synaptic pathways remain functional during the production of the swim pattern. Of the 6 identified synaptic interactions among the interneurons, 4 are excitatory and 2 are inhibitory. Excitatory interactions appear to play an important role in pattern generation.

This publication has 2 references indexed in Scilit: