COMPLETE SPARING OF HIGH-CONTRAST COLOR INPUT TO MOTION PERCEPTION INCORTICAL COLOR-BLINDNESS

It is widely held that color and motion are processed by separate para llel pathways in the visual system, but this view is difficult to reco ncile with the fact that motion can be detected in equiluminant stimul i that are defined by color alone. To examine the relationship between color and motion, we tested three patients who had lost their color v ision following cortical damage (central achromatopsia). Despite their profound loss in the subjective experience of color and their inabili ty to detect the motion of faint colors, all three subjects showed sur prisingly strong responses to high-contrast, moving color stimuli - eq ual in all respects to the performance of subjects with normal color v ision. The pathway from opponent-color detectors in the retina to the motion analysis areas must therefore be independent of the damaged col or centers in the occipitotemporal area. It is probably also independe nt of the motion analysis area MT/V5, because the contribution of colo r to motion detection in these patients is much stronger than the colo r response of monkey area MT.