ABSTRACT
Visual perception is more than simply a flow of spatio-temporal patterns from the eyes to the brain: it requires the interaction of patterns from the eyes with stored internal information. The stored information must consist of both supplements to the optical image on one hand, and information about what sorts of patterns are presently needed from vision on the other. A central problem is how these two sources of information, retinal and extraretinal, are combined; a first step in addressing this problem is to determine where and when the combining of the two sources begins.
