Dual routes to action: contributions of the dorsal and ventral streams to adaptive behavior.

More than a decade ago, Goodale and Milner proposed that our perceptual experience of the world depends on visual processing that is fundamentally distinct from that mediating the moment-to-moment visual control of our actions. They mapped this distinction between vision-for-perception and vision-for-action onto the two prominent visual pathways that arise from early visual areas in the primate cerebral cortex: a ventral "perception" pathway projecting to inferotemporal cortex and a dorsal "action" pathway projecting to posterior parietal cortex. In the years since these ideas were first put forward, visual neuroscience has advanced rapidly on several fronts. In this chapter, we examine the perception-action distinction in the light of some of these developments, giving particular emphasis to the differences in the way the two streams process visual information and the way they interact in the production of adaptive behavior.