Inhibitory effects of orientational adaptation.

Abstract

A variably oriented test grating was presented for identification in angular degrees immediately following 5-s exposure to a high-contrast grating of the same spatial frequency. The adapting grating was fixed at one of four different orientations, each located 15° away from a primary visual axis. The angle of orientation separating the adapting and the test gratings was varied from 0° to ±30° on both sides of the adapting orientation. The visibility of the test grating and its judged orientation following adaptation to the grating were compared with the same quantities following adaptation to a nonstriate control. Significant masking and tilt aftereffects were found as a function of the angle separating the test and masking gratings for every adapting orientation. The results agree with electrophysiological evidence of narrow orientation channels in the visual system and support a structural interpretation of spatially selective mechanisms that are most sensitive to the vertical and horizontal coordinates.