Sherk, Helen, Ph.D. Associate Professor F-501 (206) 543-4851 has@circ.biostr.washington.edu Work in my laboratory is aimed toward understanding how the mammalian  visual system works, particularly at the level of visual cortex.  The  focus is on the second stage of visual processing in the cortex.   In  primates and probably also carnivores, two information streams  diverge at this level, one thought to be concerned with object  recognition, and the other engaged in processing motion cues.  We are   exploring the hypothesis that, in the cat, populations of neurons in  the "motion pathway" are specialized for visual guidance of  locomotion .  To test neuronal behavior, we use large   computer-generated "movies" that simulate the view of a cat trotting  through a natural environment containing leaves, grass, bushes and  rocks.  We can change the cat's simulated direction and speed  and  simulate changes in gaze.  How animals actually use visual cues  during locomotion is a question we are now beginning to address. References Kim, J.-N., Mulligan, K., and Sherk, H.  (In  Press)  Simulated optic  flow and extrastriate cortex.  I.  Optic flow versus texture.  Journal  of Neurophysiology. Mulligan, K., Kim, J.-N., and Sherk, H.  (In Press)  Simulated  optic  flow and extrastriate cortex.  II.  Responses to bars versus  large-field stimuli.  Journal of Neurophysiology. Sherk, H., Kim, J.-N., and Mulligan, K.  (1995)  Are the  preferred  directions of neurons in cat extrastriate cortex related to optic  flow?  Visual Neuroscience 12: 887-894.