Interhemispheric transmission delays in human strabismics.

Abstract

Experimentally induced strabismus in cats and monkeys leads to a variety of anatomical, physiological, and perceptual deficits. Given the similarities between the perceptual deficits of human strabismics and those of animal models, it is reasonable to suggest similarities in the underlying anatomical and physiological deficits. In cat, one anatomic anomaly associated with strabismus is a disruption of the normal development of the posterior corpus callosum. The present study provides evidence that interhemispheric transmission in human strabismics may be disrupted also. Simple unimanual reaction times were used to examine the transmission of information through callosal fibres. Estimates of cross-callosal transmission time for strabismics were consistently longer than for individuals with no history of strabismus. This difference was found only when targets were presented within 5 degrees of the fixation point. The results suggest that human strabismics may have abnormalities in those callosal fibres which are involved in the interhemispheric transmission of visual information.