Motion after-effects in cat striate cortex elicited by moving texture

Abstract

Responses of striate cortical neurones to randomly-textured test patterns (static visual noise), or to bars of optimal orientation and width, moving back-and-forth with fixed velocity, were recorded in the lightly anaesthetized cat. Effects of prior adaptation with textured patterns drifting continuously in each cell's preferred or null directions, were assessed. Alterations of directional bias and responsiveness to the test stimulus were assessed in relation to the degree and time-course of texture adaptation. The effects of adaptation to moving texture were qualitatively similar to our previously published data on adaptation to drifting gratings in the same or similar cells. Responses to the test stimulus were transiently depressed in the direction of adaptation and enhanced following adaptation in the opposite direction, compared with responses following exposure to stationary texture. However, even in cells that were driven strongly by the adapting texture, i.e. particularly the special complex cells in cortical layers III and V, the after-effects were always weak in strength compared with those elicited by moving gratings. We conclude that, as a group, cortical cells strongly sensitive to texture motion are relatively unsusceptible to adaptation.