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PubMed · 3772695

Suppression and the pattern visual evoked potential.

K W Wright·J P Ary·T J Shors·K J Eriksen
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Abstract

We assessed the effect of amblyopic suppression on the pattern visual evoked potential (P-VEP). Since anisometropic amblyopia is associated with the monofixation syndrome and a central suppression scotoma in the amblyopic eye, patients with this functional defect were used for the study. Five anisometropic amblyopes and four normal subjects were studied using the P-VEP test. A modified haploscope was used to present a pattern stimulus to the area of suppression. By comparing responses generated under monocular conditions (non-suppression) with monocular responses under binocular viewing conditions (suppression), we measured the effect of suppression on the P-VEP. Our results show that amblyopic suppression completely abolishes P-1 amplitudes in patients with large suppression scotomas; in patients with small suppression scotomas the P-1 amplitudes were greatly reduced. Rivalry in normals also caused a reduction in P-1 amplitudes, but to a much lesser degree than that associated with anisometropic suppression. Patients with significant amblyopia did not show a rivalry effect on the P-VEP. Because the P-1 wave of the transient P-VEP is thought to represent activity at the level of the striate cortex, our results indicate that suppression probably occurs at the striate cortex or lateral geniculate nucleus.

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AmblyopiaEvoked Potentials, VisualFixation, OcularHumansReference ValuesScotomaSyndromeVision DisordersJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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K W Wright, J P Ary, T J Shors, K J Eriksen. Suppression and the pattern visual evoked potential.. https://doi.org/10.3928/0191-3913-19860901-12

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