We propose to use lesion studies to determine whether there is similar processing of color and form information in human and macaque visual cortex. Studies with macaque monkeys will continue to explore the contribution of individual cortical visual areas, with the goal of determining capabilities that are uniquely reflective of each area's activity. We have found that localized lesions in near-extrastriate visual areas V2 and V4, cause precisely retintopic losses of complex, but not fundamental, visual functions. These studies will be extended to the effects of lesions of inferotemporal visual areas TEO and TE, which receive much of their input from the above cortical areas. We will use the cumulated information we have obtained about extrastriate macaque visual areas to explore parallel organization in the human visual system. Particular attention will be paid to lesions of near extrastriate visual areas, since the visual distribution of losses can help explore parallels between human and macaque visual cortex. Our studies will focus on human cerebral achromatopsia and visual form agnosias, which are among the most dramatic disorders suggesting that human visual cortex is organized into functional modules.
