[Temporal course of disinhibition of the visual cortex neurons and their sensitivity to cross-like figures].

In acute experiments with narcotized and paralyzed cats, we studied responses of 74 striate neurons to cross-like figure under synchronous and asynchronous presentation of its lines. The aim of the study was to characterize the temporal course of interaction between three RF zones: main excitatory, end-inhibitory, and side disinhibitory ones. Previously we have found that this interaction is responsible for sensitivity to a cross in near 3/4 of cat striate cells with such sensitivity. In neurons with sensitivity to a cross, we found two types of temporal interaction between zones of RF. In the 1st type cells (14/23), the response significantly increased if the disinhibitory and the main excitatory zones of RF were stimulated simultaneously. Neurons of the 2nd type (9/23) revealed opposite temporal function: synchronous activation of RF zones evoked a minimal response. Simulation shows that the 1st type of behavior is connected with disinhibitory mechanism, while that of the 2nd type--with combination of this mechanism with convergence of orientation detectors of the previous functional level.