Walsh & Hoyt: Dorsal and Ventral Visual Streams

Two major streams of information flow are believed to exist from the V1 and V2 areas to other visual association cortices in primates: the dorsal and ventral pathways. The dorsal pathway, which is divided into dorsomedial and dorsolateral sectors, is believed to be primarily concerned with where objects are and how they could be manipulated. The ventral pathway is believed to be primarily concerned with form (i.e., what) detection, although detection of second-order motion (i.e., spatiotemporal scene variation of contrast, depth, etc., but not luminance) or biologic motion may be impaired with lesions to this pathway. The dorsal and ventral information streams do not have precise anatomic boundaries.