Directionally selective channels mediate the discrimination of moving aperiodic stimuli.

Adaptation procedures were used to demonstrate that directionally selective channels mediate the discrimination of aperiodic stimuli moving at a common speed. Subjects were adapted to a grating that drifted to either the left or the right. They then determined the orientation of the gap in a 'C' that was also moving to either the left or the right. Performance in identifying the gap orientation was most impaired when the C moved in the same direction as the adapting grating.