Anatomical Evidence for MT and Additional Cortical Visual Areas in Humans

Abstract

We stained human visual cortex for myelin, cytochrome oxidase, and the monoclonal antibody CAT-301 in an attempt to demonstrate and map MT (V5) and other visual cortical areas in humans. Both flattened and unflattened cortical tissue was examined. A likely candidate for area MT (V5), which we refer to as MT, was demonstrated using all three stains. Myelin and CAT-301 labels for MT were demonstrated to be coincident by comparing results from the two stains in adjacent sections. In all three stains, MT was an oval area approximately 1.2 x 2.0 cm, located 5-6 cm anterior and dorsal to the foveal V1-V2 border. The position and size of MT as defined by the present anatomy are consistent with MT (V5) as defined by functional measures in humans. In addition, flattened cortical tissue stained for cytochrome oxidase revealed a distinctive staining topography in several cortical areas, including areas V1, V2, MT, PX, and VX. Similar studies in flattened cortex of macaque and green monkeys demonstrated distinctive dark cytochrome oxidase staining in MT, PX, MTc, and V3.