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Mary-Kelly Mulligan, Daniel Kersten, Cheryl Olman; Perceptual modulation of V1 in the bistable translating diamond task is not retinotopically targeted. Journal of Vision 2012;12(9):1292. doi: 10.1167/12.9.1292.
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© ARVO (1962-2015); The Authors (2016-present)
Primary visual cortex (V1) neurons possess small receptive fields and their activity thus represents local scene information. However, many recent studies show that the fMRI response in V1 can be modulated by global scene structure or perceptual changes. Furthermore, perceptual modulation is not always spatially targeted to the region of visual field containing the stimulus (e.g., Williams, Nature Neuroscience, 2008). To understand the retinotopic targeting of V1 modulation during bistable perception, we used fMRI to measure activity in V1 and LOC while subjects viewed a translating diamond stimulus with occluded vertices. This stimulus results in bistable perception of either four lines moving together, with horizontal motion, or two pairs of lines with coordinated vertical motion. Stimuli were presented in an event-related design in which sets of brief presentations of the stimulus (which encourage stable perception) were alternated with extended presentation of the stimulus (which terminated after subjects reported a perceptual transition). This design allows separate analysis of fMRI response during transitions and stable percepts. Separate localizer scans identified retinotopic regions of interest in V1 containing the visible lines. During the transition trials, we measured a negative correlation between the amplitude of the fMRI response in V1 and LOC, consistent with previous reports (Murray et al., PNAS, 2002). However, this negative correlation was not present when analysis was restricted to the region of V1 representing the visible lines, nor was it present during the trials containing stable percepts.
Meeting abstract presented at VSS 2012
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