Postoperative recovery from collicular lesions in rats: A dissociation between seeing and orienting

The human brain contains two quasi-distinct visual systems operating in parallel, each originating in the primary visual cortex. The ventral (occipitotemporal) stream, codes information as a semantic representation suitable for storage and for deploying off-line in cognitive processes such as imagining, recognizing, and planning. It provides the visual contents of our perceptual experience. The dorsal (occipitoparietal) stream serves the more immediate function of guiding our movements visually from moment to moment, and so needs to code transitory ‘here and now’ information in an egocentric format. Its contents appear not to inform cognitive processing, and to be inaccessible to conscious monitoring.