Hemispheric
Processing of Binocular Retinal Disparity
K. Shimono, M. Kondo, K. Shibuta & S. Nakamizo |
Depth
discrimination of large disparities (2 degrees) presented in the
peripheral visual fields was investigated for ten stereoanomalous
observers who could not discriminate among three types of disparity
(crossed, uncrossed, and zero) presented symmetrically about the
fixation point in the mid-sagittal Mane, i.e., midline stereopsis.
Seven out of the ten could detect all or some types of disparity
and the other three could not detect any type of disparity. The result
is not compatible with Richards' suggestion that for midline stereopsis
to be normal, stereopsis in both hemispheres also has to be normal.
Rather, the fact suggests that disparity detectors in each hemispheres
are independent from disparity detectors correlating disparity information
from both hemispheres. The trouble with the interhemispheric link
which is requisite for correlating disparity information from both
hemispheres is thought as one of the causes of stereoanomaly in midline
stereopsis.
|