ABSTRACT
Visual perception is more than simply a ftow 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.
