INDEPENDENT CODING OF WIND DIRECTION IN COCKROACH GIANT INTERNEURONS

In this study we examined the possible role of cell-to-cell interactio ns in the localization processing of a wind stimulus by the cockroach cereal system. Such sensory processing is performed primarily by pairs of giant interneurons (GIs), a group of highly directional cells. We have studied possible interactions among these GIs by comparing the wi nd sensitivity of a given GI before and after removing another GI with the use of photoablation. Testing various combinations of GI pairs di d not reveal any suprathreshold interactions. This was true for all un ilateral GI Fairs on the left or right side as well as all the bilater al GI pairs (left and right homologues). Those experiments in which we were able to measure synaptic activity did not reveal subthreshold in teractions between the Gls either. We conclude that the GIs code indep endently for a given wind direction without local GI-GI interactions. We discuss the possible implications of the absence of local interacti ons on information transfer in the first station of the escape circuit .