Single unit activity and visual perception of motion.

Extracellular recordings were carried out in the primary visual cortex of behaving macaque monkeys. Neurons were activated by moving a visual stimulus across their receptive fields during steady fixation and by moving their receptive fields (by visual tracking) at the same velocity across a stationary visual stimulus. Out of a total number of 123 cells studied, 111 were activated by the visual stimulation both during fixation and tracking. The remaining 12 cells showed good response during fixation and very weakened response during tracking. Our results show that a small percentage of striate neurons in macaque monkey could discriminate between the real motion of an object in the visual world and the self-induced displacement of its retinal image.