Motion Processing in Monkey Striate Cortex

Abstract

Motion processing, i.e., the processing of retinal image movement, is of great importance for primates (for review, see, e.g., Nakayama, 1985). In fact, motion processing could be considered fundamental to vision since retinal images are always moving as a result of micro eye movements, essential for visual perception. However, retinal image motion, whether generated by micro or macro eye movements, including pursuit and saccades, contains no information about the outside world. This is not the case for retinal image motion generated by the subject’s own movements. The spatiotemporal changes in the retinal light distribution induced by relative movement between the observer and the environment, generated either by object motion or by self motion, are referred to as optic flow. Optic flow is a rich source of information about the outside world. It provides information about the 3-D trajectory of moving objects of the moving subject as well as about the 3-D structure of the environment. Furthermore, motion is a clear signal for image segmentation and perceptual grouping. In addition to its many perceptual uses, retinal motion also contributes to the control of eye movements, saccades as well as pursuit and optokinetic nystagmus. The term motion processing generally refers to the analysis of retinal image motion inasmuch as this leads to control of eye position and to extraction of information about the outside world.