Sherk, Helen, Ph.D.
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.
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.