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Guldehan Durman, Yaseen A. Jamal, Derek Hu, Eva M. Ratai, Daniel D. Dilks; Rapid reorganization in adult human primary visual cortex (V1) and consequent perceptual elongations are mediated by GABA. Journal of Vision 2020;20(11):288. doi: https://doi.org/10.1167/jov.20.11.288.
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© ARVO (1962-2015); The Authors (2016-present)
When deprived of its typical visual input, the adult human primary visual cortex (V1) starts to reorganize within minutes, directly affecting visual perception (e.g., squares are perceived as rectangles). But what is the mechanism underlying such rapid neural and perceptual changes? Here we use magnetic resonance spectroscopy (MRS) and psychophysics to show that the inhibitory neurotransmitter, GABA, is the initial driver of reorganization in adult human V1. Specifically, we patched one eye in typical children, adults, and seniors, thereby depriving the cortical representation of the blind spot (BS) of its typical visual input. In adults, using MRS, we then found a significant reduction in V1 GABA concentration within just minutes of deprivation (relative to no deprivation), and, moreover, that this magnitude of GABA reduction closely predicted the extent of perceptual distortion near the BS after deprivation. Additionally, using psychophysics, we found that the magnitude of such perceptual distortions was reduced in kids and seniors relative to adults, thus mirroring the inverted U-shaped pattern of V1 GABA concentration across the lifespan. Taken together, these results provide converging neural and behavioral evidence that the disinhibition of preexisting connections ignites rapid cortical reorganization in the adult human visual system, and raise the intriguing question of whether and how additional changes continue to occur during subsequent, longer periods of deprivation.
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