Karen R. Dobkins

Department of Psychology, University of California, San Diego, CA, USA

Color Contribution to Motion Processing: Where in the Brain does it Come From?

The degree to which the primate visual system uses information about object color has been a long-standing debate in vision science. We have been investigating this issue by conducting psychophysical experiments in human subjects (both infants and adults) as well as single-unit neurophysiological experiments in motion area MT of awake behaving rhesus monkeys. Contrary to the much-heralded story of a "color-blind" motion system — which sprang from notions of parallel processing for "color" and "motion" within parvocellular (P) and magnocellular (M) pathways, respectively — we find that the motion system uses red/green color information in unique and significant ways. Based on the nature and effectiveness of chromatic input to motion processing, we suggest that chromatic motion processing is governed largely by "second-hand" chromatic responses originating in the M pathway. In some experimental conditions, however, we find a small degree of P pathway input. Interestingly, human infants show evidence of greater P pathway input to motion processing than do adults, suggesting that inputs to motion areas become more specialized over the course of development.

This page was last updated on 16 Feb 2001.

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