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Simon Clavagnier, Reza Farivar-Mohseni, Bruce C Hansen, Robert F Hess; Does V1 primarily encodes Spatial Frequencies or Features ?. Journal of Vision 2013;13(9):1235. doi: 10.1167/13.9.1235.
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© ARVO (1962-2015); The Authors (2016-present)
t is now well-accepted that neurons in V1 cortical area are affected by visual information outside of their classic receptive fields. Recently it has been proposed that V1 neurons may differentiate between meaningful structures in an image as opposed to noise. If V1 neurons are indeed responsive not only to the spatial frequency content of an image but also to its structure, then a manipulation that maintains the spatial frequency content but disrupts image features should differentially affect V1. We mapped the fMRI V1 responses of volunteers while they were watching a high-resolution continuous video of natural scenes. The structure of that video was modulated in band-selective phase scrambling, whereby the phase values corresponding to the spatial frequency content in a band were maintained while outside of the band, they were scrambled. Eccentricity maps were used as topographical references. We found that despite the identical spatial frequency content in the movie, V1 responses were selective for phased-aligned content, and diverting attention did not affect the pattern of responses. But filtering the movie such so as to preserve one frequency band with scrambled phase values did not have a similar response. The results suggested that the pattern of activity in V1 area is reorganized depending if the spatial frequency content of an image give rise to perceptually relevant structure or not.
Meeting abstract presented at VSS 2013
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