Semester

Summer

Date of Graduation

2006

Document Type

Thesis

Degree Type

MS

College

School of Medicine

Department

Pathology, Anatomy and Laboratory Medicine

Committee Chair

Janine D Mendola

Abstract

Binocular suppression has been previously studied psychophysically and with VEPs. Here we used functional magnetic resonance imaging (fMRI) to image activity in visual cortex while human subjects with normal vision or amblyopia experienced binocular integration. One eye viewed a dynamic grating pattern. The other eye viewed one of four stimuli, i.e., black mask, gray mask, or two grating masks that varied in contrast. We observed a luminance masking effect, that is, when the gray mask is compared to the black mask, there was less activation in many retinotopic areas (consistent with previous VEP studies). The result was observed in all control subjects. Interestingly, in the anisometropic subjects there was a pronounced asymmetry in the luminance masking effect, with the stronger effect seen when the fellow eye was masked. We conclude that interocular suppression studied with fMRI may be related to the concept of binocular suppression scotomata in subjects with amblyopia.

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