When a single object lies in front of or beyond the plane of fixation its retinal image lies on disparate positions in the two eyes. This 'local' retinal disparity is an excellent cue to depth, and retinal disparties of a few seconds of arc are detectable by people and monkeys. However, most visual scenes produce a complex array of contours in each eye and we can detect the disparity in the arrays despite the ambiguous nature of the disparities, i.e. each contour in one eye could be related to any of several similar contours in the other eye. This ability, known as 'global' stereopsis, may be selectively impaired following brain damage in man. Global stereopsis was measured in rhesus monkeys before and after removing a different cortical visual area in different groups of animals. Only removal of the inferotemporal cortex impaired global stereopsis. The result is related to the findings with human patients and to receptive field properties of neurons in the inferotemporal cortex of monkeys.
Which visual functions depend on intermediate visual regions? Insights from a case of developmental visual form agnosia
Reinstatement of binocular depth perception by amphetamine and visual experience after visual cortex ablation
Contribution of inferior temporal and posterior parietal activity to three-dimensional shape perception
Microstructural properties of the vertical occipital fasciculus explain the variability in human stereoacuity
Brain Injury & Trauma
brain injury after impact to the head is due to both immediate mechanical effects and delayed responses of neural tissues.