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.