Meeting Abstract

80.1  Sunday, Jan. 6  The Synaptic Connections of a Multifunctional Network in Tritonia diomedea CAIN, Shaun D; Eastern Oregon University shaun.cain@eou.edu

One of the emerging principles in neuroethology is the prominence of multifunctional networks in the control of behavior. In the sea slug Tritonia diomedea, for instance, the well described swim central pattern generator synapses on motoneurons that control the dorsal and ventral musculature that drives swimming when the CPG is configured to fire rhythmically. Swim bouts, however, are infrequent and short-lived. During periods of between swim bouts, tonic firing of a subset of CPG neurons (the DSIs) either promote or enhance the activity of identified cilio-motor neurons. These cells, the paired Pd5 and Pd6, directly innervate the ciliated foot epithelium and participate in the control of ciliary beat frequency that regulates the rate of crawling in T. diomedea. In this study, I investigated the neural connections between the excitatory Pd5 and Pd6 cells. During tonic firing of the DSIs, these connections appear to be monosynaptic excitatory connections. These connections are altered during swimming such that the PD5 and Pd6 cells are first excited, followed by an extended inhibition. Subsequent tonic firing of the DSIs returns the synapse to a monosynaptic excitatory connection. In addition, I investigated the relation of CPG activity to the activity of the paired Pd7 neurons. The Pd7 cells are inhibited by activity in the DSIs. The Pd7 cells are hypothesized to be involved in chemosensory behavior. If this is the case, the CPG neurons are indeed a multifunctional network, controlling swimming, crawling, and sensory input that drives this network.