Bilateral form deprivation in monkeys. Electrophysiologic and anatomic consequences.

This content is PDF only. Please click on the PDF icon to access.

Abstract

The response characteristics of neurons in the striate cortex are described for rhesus monkeys that underwent bilateral form deprivation by surgical closure of the eyelids starting within the first month of life and lasting for 2, 6, 7, 13, or 16 weeks. The monkeys had been tested for visual deficits resulting from these experimental deprivations. Single-unit recordings from the striate cortices of these animals showed a single significant abnormality; the absence of excitatory binocular input. Whereas, 76% of the neurons in the foveal striate cortex of the normal animals were binocular, fewer than 20% of the neurons in the experimental monkeys were binocular. However, each eye was well represented by monocular cells. As demonstrated in oblique microelectrode penetrations, the cortical eye-dominance zones for each eye appeared to be of equal width with sharp transitions at the monocular boundaries. The sizes of the cells of the lateral geniculate nuclei were smaller (-15%) than those in controls. Binocular form deprivation early in life has its most obvious effect on the physiology and function of cortical binocular neurons and secondarily on the size of neurons of the lateral geniculate nucleus.