YAFREMAVA, Liudmila*; GILLETTE, Rhanor; University of Illinois at Urbana-Champaign: Multiplexed function in Serotonergic Neurons of Gastropod Molluscs

A group of serotonergic neurons is highly conserved in cerebral ganglion lobes of opisthobranch and pulmonate gastropods. Known as the As1-4 group in Pleurobranchaea californica and the DSI neurons in Tritonia diomedia, these neurons were first discovered to be elements of the escape swimming motor networks. Subsequent studies in different labs showed that their functional roles were multiplexed. These cells act in defensive withdrawal, avoidance and orienting turning, and in locomotor command. Knowledge of the circuit and behavioral contexts within which they act can suggest the evolutionary history of acquisitions of function in these neurons. In particular, studies of the sensory and motor pathways that mediate the computations of turn responses to specific appetitive or noxious stimuli provide a highly ordered framework with predictive power for inferring evolutionary history.