Experiments on the neural basis of movement vision.

Abstract

The capacity of pigmented and albino guinea pigs to respond to moving visual stimuli was investigated by means of the rotating drum method. A mechanical recording system permitted registration of the nystagmic reactions of the head produced by the moving stripes of the drum. Threshold velocities of movement vision in the pigmented guinea pig are almost double that of albino animals, and, under comparable conditions, are equal to the maximal velocities of movement at which the cat and the human individual respond. The head nystagmus of the guinea pig, like eye nystagmus, varies as a function of the velocity of the movement. Cortical operations, involving removal of the occipital areas of the brain, hemidecortication, hemidecortication combined with removal of the occipital area of the other hemisphere, and complete bilateral decortication, produce no significant change in maximal velocity thresholds in pigmented guinea pigs. However, the extirpation of one hemisphere increases the frequency of nystagmic reactions toward the side of the lesion at velocities where responses occur. Bilateral decortication raises the frequency of response in both directions of movement. The principle function of the cortex in movement discrimination in the guinea pig is the regulatory control of subcortical centers which directly mediate this function and determine the rate of the pursuit reactions.