BINOCULARITY IN PRISM-REARED MONKEYS

Prismatic binocular dissociation in infant monkeys mimicked a concomit ant squint. Within 3 weeks, the numbers of binocular neurons in the pr imary visual cortex were reduced by half and did not recover with up t o 5 years of subsequent unrestricted binocular visual experience. The monkeys failed to show binocular summation for spatial contrast sensit ivity tasks and were unable to utilise horizontal binocular disparitie s in random-dot stereograms - two indices of stereoblindness. Electrop hysiological analysis of the V1 and V2 cortices showed a dramatic redu ction in binocular neurons. Analysis of interocular spatial phase tuni ng functions showed a conspicuous loss of excitatory binocular drive i n V1 neurons which was sufficient to account for many of the defects i n binocular function.