Color and luminance share a common motion pathway

Abstract

Following exposure to a moving grating of bars differing only in luminance, a motion aftereffect (MAE) is observed on a stationary grating of bars differing only in chrominance. This suggests that the motion of equiluminous chromatic stimuli is sensed by a channel that responds to both luminance and chrominance and not by a separate channel specialized for the motion of colored stimuli. However, adding color to a low contrast luminance stimulus actually reduces its effectiveness at creating or nulling a MAE, indicating that the response of the motion pathway to color is qualitively different from its response to luminance. In addition, a chromatic stimulus demonstrates a dissociation between perceived speed, MAE speed and speed required to null the MAE that is absent for a luminance stimulus.