![]() Local clustering of peak voxel responses to disparity (“preferences”) in simulated and empirical datasets. Data are cut through the cortical depth along a line extending from the foveal representation of V3A up to the periphery near the border with V3d. D, Sliced view of peak disparity responses in the same ROI (Participant 2, left V3A). Note that to assist visualization the cortical depth, dimension is not drawn to scale. The flattened representations for each cortical depth were stacked together and an opacity gradient was applied to aid visualization of peak disparity response across the cortical depth. C, The same ROI in Participant 2, but now represented across 11 relative points through the entire range of the cortical sheet (0 to 1 relative depth, sampled at increments of 0.1). Coarse clusters of peak disparity responses do not overlap with the potential location of large veins. Gray dashed lines delineate areas with low signal amplitude in both maps. ![]() The white dashed line represents the outline of left V3A shown above. Dark areas indicate areas of low absolute signal in the EPI images, and are likely to represent large veins. B, Mean BOLD signal amplitude in the same ROIs. Peak disparity responses were sampled from three intermediate layers of the cortical sheet (at relative depths of 0.4, 0.5, and 0.6) and averaged across depths. Dark and light gray areas represent sulci and gyri, respectively. The peak disparity response of each voxel is mapped onto flattened representations of the cortex. A, Peak disparity responses in left V3A of Participants 1 and 2 (first session). Spatial distribution of peak disparity responses in area V3A for two participants. Error bars depict the SEM across subjects and sessions ( N = 16). Chance performance (16.7%) is indicated by the dashed gray line. G, Mean prediction accuracy for the discrimination of individual disparity conditions presented within each session (six-way classification). Chance level (50%) is indicated by the dashed gray line. F, Mean prediction accuracy for the discrimination of crossed “near” versus uncrossed “far” disparities across early and dorsal visual areas (two-way classification). E, Mean percent-signal change for stimulation versus blank periods across all subjects and sessions ( N = 16). D, Signal changes in response to stimulus delivery (stimulus vs rest) for Participant 1, showing that activity is localized to the gray matter. Slice placement is illustrated here on a near midsagittal slice in Participant 1. C, BOLD signals were acquired from dorsomedial visual cortex. B, The depth of the wedges was defined by manipulating disparity in random dot stereograms, which were viewed through red-green anaglyphs attached to prism glasses. Four disparity-defined wedges were simultaneously presented at 1 of 6 disparity-defined depths during each imaging session (☓, 9, and 15 arcmin in sessions 1 and 2 ☑2, 24, and 36 arcmin in Session 3). A, Diagram of the depth arrangement in the stimuli. Schematic illustration of the stimuli and basic functional activations.
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