THE TIMING OF PROCESSING ALONG THE VISUAL PATHWAY IN THE CAT

We obtained visual response latencies and response durations following visual stimulation of neurones recorded in the lateral geniculate nucleus (LGN), areas 17, 18, 19, the posteromedial lateral suprasylvian sulcus (PMLS), and area 7 of the cat. We found an increasing lengthening of the mean response latencies, consistent with the view of a progressive advance of processing from stage to stage. However, we also observed a substantial and increasing scatter in these latencies. Moreover, response durations vastly supersede this gradual increase in latencies. Taken together, these results suggest that most of the neurones within different stages of a hierarchically organized sensory pathway are simultaneously active when stimulated. Implications of a time-based processing scheme for models of information processing in highly interconnected, multi-layered systems are discussed.