Our overall objective is to determine how information is processed in the cortical visual areas in primates and ultimately to ascertain the role of each cortical visual area in the behavior of primates, including man. Our principal technique is to record with microelectrodes the responses of single neurons in the cortical visual areas to otpical stimuli. We have 2 specific objectives: (1) Determine the specialized function of each of the 6 separate representations of the visual field that are located in the third tier and in the middle temporal area (MT) in New World monkeys. (2) Record the activity of single neurons in the visual cortex in alert behaving monkeys while the animals are experiencing binocular rivalry. We have trained monkeys to report the alternating changes in perception that occur in binocular rivalry induced by presenting different stimuli to each eye. We seek to determine whether the activity of visual cortical neurons changes during binocular retinal rivalry and discover the mechanism by which input from each eye is alternatively suppressed.