Global Motion Processing in Human Visual Cortical Areas V2 and V3

Abstract

Humans can readily detect the overall direction of movement in a flock of birds despite large differences in the directions of individual birds at a given moment. This ability to combine disparate motion signals across space underlies many aspects of visual motion perception and has therefore received considerable research attention. The received wisdom is that spatial integration of motion signals occurs in the cortical motion complex MT+ in both human and nonhuman primates. We show here that areas V2 and V3 in humans are also able to perform this function. We suggest that different cortical areas integrate motion signals in different ways for different purposes.