ORGANIZATION OF RECEPTIVE-FIELDS OF CRICKET GIANT INTERNEURONS REVEALED BY CEREAL ABLATIONS

In order to determine the contribution of each cercus and its receptor s in organizing the receptive field of four air-motion sensitive giant interneurons (Gls 8-1, 9-1, 9-2 and 9-3) of the cricket Gryllus bimac ulatus, effects of removing the ipsilateral or contralateral cercus (r eferred to the side of the axons) on specific parameters of the wind-e voked responses of these neurons were investigated. All 4 Gls received only excitatory inputs from a group of filiform hairs on the ipsilate ral cercus. In addition to the ipsilateral excitatory inputs, Gls 8-1 and 9-1 received weak excitatory and strong inhibitory inputs from a g roup of filiform hairs on the contralateral cercus. Gl 9-2 received on ly inhibitory inputs from filiform hairs on the contralateral cercus. Gl 9-3 received excitatory inputs from filiform hairs on the contralat eral cercus and no inhibitory input was confirmed. In addition to such simple excitatory and inhibitory connections, the rebound motion of c ereal filiform hairs had some role in organizing the receptive fields of Gls 9-2 and 9-3. Furthermore, the possibility of using a rebound de polarization of the membrane potential for mediating the long latency response in Gls 8-1 and 9-2 will be discussed.