Projections of extraocular muscle afferents to the visual cortex in the cat

Abstract

The effect of afferent impulses from the extraocular muscles on the activities of neurons in visual cortex area 17 was studied in adult cats anesthetized with nitrous oxide. The neurons responding continually to visual stimulation (sustained cells) of the left eye showed no response whatsoever to stretch stimulation of the right extraocular muscles or oculomotor nerve stimulation. Of the neurons responding transiently to visual stimulation (transient cells), some showed suppression of responses to visual stimulation and subsequently gave spike discharges when the extraocular muscle was stretched simultaneously with visual stimulation, and others responded to single stimulations of the oculomotor nerve as well. This effect makes an object clear just after completion of the saccadic eye movement and will be of help in the fixation reflex.