Behavioural correlates of activity in the giant cerebral neurons of Archidoris

Abstract

A behavioral study was made of the paired giant neurons in the cerebral ganglia of the nudibranch mollusk A. pseudoargus. Intracellular recordings were made from the giant cells in the isolated brain and in whole animal preparations. Both neurons responded to shadowing stimuli and to tactile or chemical stimulation of the body surface, with ipsilateral input being more effective for each neuron than that of the contralateral side. Both cells showed different modes of firing associated with spontaneous movements of the mantle, spontaneous and reflex gill withdrawal and closure of the mantle over the retracted gill. Direct stimulation of either neuron elicited movements of the mantle edge or retraction of the gill.