Vision in Monkeys with Lesion of the Striate Cortex
Recent studies have made major advances in the methods and techniques for determination of sensory capacities of animals. Our confidence in the results of such studies is strengthened by the replicability of thresholds from animal to animal, and the frequent similarity between measures of animal and human sensory functions. One natural application of animal psychophysics is to use the same methods for evaluation of sensory capacities in animals with lesions, in the expectation that such studies may help towards understanding the nature of sensory processing by the brain. For example, if a sense organ projects independently to two or more places in the brain, we might learn more about possible differential functions of these central structures by ablating one or the other, and testing residual sensory capacity. In the case of vision, we might destroy the striate cortex or the superior colliculus and attempt to determine the nature of the visual loss. Along with anatomic and physiologic data, behavioral study of lesion effects would help in analysis of the functional capacity of these two parallel visual pathways. We might determine the effects of such lesions on photopic and scotopic brightness thresholds, visual acuity, and the ability of the animals to discriminate form, color, and movement, and thus evaluate the capacity of the surviving visual structures. We must recognize, of course, that in the example given, the geniculocortical and collicular circuits are not completely independent.
KeywordsSuperior Colliculus Striate Cortex Discrimination Problem Sensory Capacity Lateral Geniculate Body
Unable to display preview. Download preview PDF.