Perception of Motion , Depth , and Form

IN VISION, AS IN OTHER mental operations, we experience the world as a whole. Independent attributes—motion, depth, form, and color—are coordinated into a single visual image. In the two previous chapters we began to consider how two parallel pathways—the magnocellular and parvocellular pathways, that extend from the retina through the lateral geniculate nucleus of the thalamus to the primary visual (striate) cortex—might produce a coherent visual image. In this chapter we examine how the information from these two pathways feeds into multiple higher-order centers of visual processing in the extrastriate cortex. How do these pathways contribute to our perception of motion, depth, form, and color?