College of Optometry Faculty Proceedings, Presentations, Posters, Speeches, Lectures, etc.

Title

Effects Of Binocularly Conflicting Signals On The Maturation Of Monkey Primary Visual Cortex (V1)

Format

Poster

Conference Title

Society of Neuroscience Annual Meeting

Organization/Association/Group

Society of Neuroscience

Location

San Diego, California / November 10-15. 2001

Publication Date / Copyright Date

11-14-2001

Abstract

We investigated the effects of rearing monkeys under three contrasting abnormal visual conditions on V1 development: 1) optical strabismus in which both eyes maintained relatively clear images, but the two images were never fused (prism-reared monkeys), 2) daily alternating defocus in which binocular imbalance occurred primarily in high spatial frequency ranges (lens-reared monkeys), and 3) alternating monocular occlusion in which infant monkeys experienced an extreme binocular imbalance but clear vision in each eye for 6 hours every day (occluder-reared monkeys). The rearing began at 4 weeks of age and continued until 4 months of age. When the monkeys were mature, we investigated the monocular and binocular response properties of V1 neurons. We found that the sensitivity of V1 neurons to interocular image disparity was severely reduced in all experimental monkeys. However, for the alternating defocus group, the disparity sensitivity loss was found for those units tuned to higher spatial frequencies and proportional to the power of defocusing lenses. Interocular suppression was far more prevalent in strabismic monkeys than in lens-reared monkeys, and the occluder-reared monkeys showed the least amount of suppression. In contrast, the spatial resolving power of units was not significantly reduced in prism-reared monkeys, whereas units in lens-reared and occluder-reared monkeys showed substantially lower spatial resolutions. These findings highlight the differential effects of experiencing a variety of binocularly discordant signals early in life on V1 maturation, and better define the constraints imposed by V1 neurons on binocular vision development.

Disciplines

Optometry

Keywords

visual cortex, binocular, development, monkey

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