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En Zhang, Gong-Liang Zhang, Wu Li; Spatiotopic location specificity of perceptual learning in orientation discrimination. Journal of Vision 2012;12(9):1140. doi: 10.1167/12.9.1140.
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© ARVO (1962-2015); The Authors (2016-present)
Our recent study has shown that the location specificity in motion perceptual learning is not entirely retinotopic, but rather, it shows a remarkable spatiotopic component (Zhang & Li, PNAS 2010), suggesting a pliable spatiotopic processing mechanism in the dorsal visual areas representing the spatial relations of stimuli. In the present study, we investigated whether spatiotopic specificity could also exist in orientation discrimination learning that has been shown to engage the ventral visual pathway. The possible mechanisms underlying spatiotopic perceptual learning was also explored. Human subjects were trained to discriminate an orientation difference between two arrays of randomly positioned iso-oriented bars that were successively displayed at either the same or different spatial location, with their retinal locations kept unchanged by introducing a gaze shift between the two stimuli. We found that the learning was specific to the relative location of the two stimuli in spatiotopic frame of reference, and that this spatiotopic effect was seen only at the trained orientation and at the trained retinal location. This suggests plasticity in spatiotopic processing mediated by retinotopic cortex along the ventral visual pathway. Moreover, similar spatiotopic effect was also observed by randomizing the orientation of individual bars in the first stimuli, rendering it irrelevant to the orientation discrimination task over the course of training. However, when the first stimulus was hidden and thus any spatial attention triggered by the onset of the first stimulus was removed during training, the spatiotopic specificity was absent. These results suggest that predictive remapping of attention plays an important role in spatiotopic perceptual learning. Taken together, our observations suggest that perceptual learning can specifically modify spatiotopic visual processing, which may engage an interaction between retinotopic visual areas and higher-order spatiotopic attention mechanisms.
Meeting abstract presented at VSS 2012
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