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Chao Han, Haoran Xu, Ming Chen, Peichao Li, Shude Zhu, Zijing He, Haidong Lu; Boundary contour of binocular rivalry stimulus affects activities in ocular dominance columns (V1) of anesthetized macaque monkeys. Journal of Vision 2012;12(9):42. doi: 10.1167/12.9.42.
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© ARVO (1962-2015); The Authors (2016-present)
Psychophysical studies reveal that perceptual dominance during binocular rivalry (BR) is predisposed to the rivaling image with the strong boundary contour (BC) (Ooi and He, 2006). To reveal whether such a BC-based BR perception can be contributed by activities in cortical area V1, we used intrinsic signal optical imaging to measure the neuronal population response in anesthetized and paralyzed macaque monkeys. The basic BR stimulus comprised a 1.5 deg grating disc (3 cpd) surrounded by an orthogonal grating background (5x5 deg) in one half-image (fixed-BC). The other half-image had a grating disc whose orientation was orthogonal to the fixed-BC grating disc. The saliency of the disc's BC was manipulated by phase-shifting its grating relative to the surrounding grating of the same orientation (variable-BC). Increasing the phase-shift strengthens the BC. We rendered the BR stimulus in orthogonal motion (2 c/sec) and measured cortical activities in 3.5-second windows. We found clear ocular dominance maps corresponding to the eye exposed to the fixed-BC half-image. The strength of the ocular dominance pattern decreases as the BC strength in the fellow half-image (variable-BC) increases. This trend parallels the human psychophysical observations of BC strength influence on BR. We also found the ocular dominance/suppression-like activities are stronger in the cortical areas representing the BC than those representing the interior of the grating disc. Separately, we used pattern classification method to estimate the dynamic dominance scores based on sampling at 4 Hz over 60 seconds. We found a longer mean dominance duration associated with the eye simulated with strong BC. Altogether, the similarity between the macaque V1 neuronal population responses and human psychophysics indicates V1 contributes to BC-based BR. More generally, the data suggest BR is an integral mechanism in binocular surface representation.
Meeting abstract presented at VSS 2012
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