PMC

Peak probability values for the FPM. The peak probability value was calculated for each ROI in both the SBA and VBA. In general, this value was higher in SBA than VBA across all ROIs (P << 0.001, paired t-test).

The effect of anatomical variance on the surface-based probabilistic atlas. Anatomical variance was quantified by sulci and gyri convexity. The nodal-based mean (A) and variance (B) of the convexity are shown on brain surfaces for visualization purposes. The ROI-based mean variance and standard error of the convexity for each ROI averaged across both hemispheres in MPM across the subjects is also shown (C). Significant correlations between mean convexity variance and peak probability value (D) and blurring metric (E) were observed across the ROIs. Marker conventions for individual ROIs are as in Figure .

Blurring metric in SBA (A) and VBA (B). The blurring metric is a measure of how well ROIs from individual subjects overlap in the standardized space. As this metric may be sensitive to subjects with atypical ROI locations, we calculated the blurring metric using a pooled volume defined as the full extent of the FPM (A) and after first excluding regions that were covered by less than 5% of all subjects (B). In both cases, the blurring metric was always lower for the SBA and this difference was highly significant across all ROIs (P << 0.001, paired t-test).

Resting-state functional connectivity across all ROIs in the probabilistic atlas. Values represent Fisher transformed correlations averaged across both hemispheres and 4 resting-state runs. (A) From a representative subject, functional connectivity matrix is calculated for surface-based atlas (left), subject-specific ROIs in the native volume space (center) and volume-based atlas with nonlinear transformation to the same native volume space (right). (B) The group-averaged functional connectivity is displayed using the same conventions. Notably, two panels of each column show similar distribution, which indicates strong connectivity within ventral–temporal, dorsal–lateral and parietal–frontal ROIs, as well as between two parts of ROIs, but weak connectivity between ventral–temporal (and dorsal–lateral) ROIs and parietal/frontal ROIs.

Leave-one-out validation of FPM. Central tendency calculated for all pairwise comparisons of ROIs in the leave-one-out FPM and ROIs defined in independent individual subjects for the SBA (A) and VBA (B). For example, V1v of leave-one-out FPM (y-axis) is compared with all subject-specific ROIs (x-axis) in the ventral–temporal portion of cortex from V1v to PHC2. For all panels shown, higher values consistently fall along the diagonal, with values gradually decreasing away from the diagonal. This analysis validates the use of the FPM for use with novel subjects that did not contribute to the atlas generation. Conventions are the same as in Figure .

Leave-one-out validation of MPM. Proportion overlap calculated between all pairwise comparisons of ROIs in the leave-one-out MPM and ROIs defined in independent individual subjects for the SBA (A) and VBA (B). For example, V1v of leave-one-out MPM (y-axis) is compared with all subject-specific ROIs (x-axis) in the ventral–temporal portion of cortex from V1v to PHC2. For all panels shown, higher values mainly fall along the diagonal, with values gradually decreasing away from the diagonal. This analysis validates the use of the MPM for use with novel subjects that did not contribute to the atlas generation. Conventions are the same as in Figure .

Central tendency metric in surface (A) and volume (B) based atlases. For all panels, the highest values consistently fall along the diagonal, with values gradually decreasing away from the diagonal. For convenience, data are divided into 3 groups of ROIs (ventral–temporal, dorsal–lateral and parietal areas). Note, however, that V1d is included with ventral–temporal ROIs, and V3a and V3b are included with parietal ROIs so that all neighboring ROIs (i.e., those that share a border) can be directly compared in at least one of the panels. The frontal region hFEF is not displayed because no other ROIs in the atlases border hFEF and thus we do not expect any non-zero off-diagonal values for hFEF.

Visual field coverage for all ROIs in the SBA MPM. Polar angle histograms of the visual field coverage of the MPM projected onto novel subjects using the leave-one-out SBA. Polar angle phase values were extracted from data obtained using the retinotopy (A and B) or memory-guided saccade task (C) and concatenated across all subjects. Thick lines show the visual field coverage for the left (black) and right (gray) hemispheres as a proportion of the total coverage of an ROI. The thin-lined vectors represent the mean phase for a given ROI. As expected, all MPM ROIs projected to regions with a clear contralateral bias.

Comparison of subject-specific ROI size with that of the MPM in surface and volume space. (A) Comparison of the surface area of subject-specific ROIs (gray bars) and the average surface area of the SBA MPM ROIs (MPM, black bars). (B) Comparison of the volume of subject-specific ROIs (gray bars) and the VBA MPM ROIs (black bars). In both cases, the largest discrepancies were observed for higher-order topographic regions. Error bars denote 95% confidence intervals. (C) A direct comparison of the MPM ROI size for the VBA versus the SBA, presented as a proportion of the average subject-specific ROI size. Compared with the VBA, MPM ROI size for the SBA better reflected the subject-specific ROI size (P << 0.001, paired t-test). Data for individual hemispheres are presented in Supplementary Figure 5.

An exemplary FPM of the right hemisphere V1d. The color-coded nodes in the SBA (A) and voxels in the VBA (B) denote the probability of that node or voxel being assigned to the right V1d across subjects (n = 50). The probability gradually increases from blue to red indicated by the color scale. In both panels, higher probabilities are located more centrally within the full distribution accounting for the majority of the variance in anatomical location across subjects (see central tendency measure for more details). For comparison, the black line denotes the border of the MPM for V1d, which is a function of the FPMs for all ROIs (see Fig. ).

MPM of visual topography. (A) Schematic presentation of the algorithm for generating the MPM. For the ith element, the probability of being assigned to region R1 (red), region R2 (blue) and outside visual topography (white) is 35, 25 and 40%, respectively. First, we combined the probability arranged in visual topographic areas together and compared with the outside one. Then choosing the maximum probability over all candidates within visual topography takes the ith element to be assigned to region R1. MPMs are displayed in both surface (B) and volume (C) space. Each color-coded area denotes a specific visual ROI. The surface MPM (B) shows the same overall structure as seen in individual subjects (see Fig. ). The color map is the same for both surface and volume space.

Schematic borders of 25 topographic visual regions from a representative subject. The areas outlined on the inflated cortical surface were delineated in individual subjects and used to generate the surface-based atlas. Note that ventral (upper visual field) and dorsal (lower visual field) representations for early visual cortex areas V1–V3 were defined separately. Note also that the grouping of ROIs into ventral–temporal (lower legend), dorsal–lateral (middle legend), and parietal–frontal (upper legend) is only for the purpose of organizing the presentation of the data and should not be taken to indicate distinct information processing hierarchies of the visual system. Example polar angle maps from individual subjects are presented in Supplementary Figures 1–3.

Group-averaged phase maps and comparison with MPM. Average phase values across subjects for dorsal–lateral (A) and ventral–temporal (B) regions obtained from the retinotopy task, and parietal and frontal regions (C) obtained from the memory-guided saccade task. The color code indicates the region of the visual field to which each surface node responded best, on average, across subjects. Data are only shown for nodes with a variance less than or equal to 0.80 (retinotopy task, A and B) or 1.20 radians (memory-guided saccade task, C; see also Supplementary Fig. 4 for retinotopy task). ROI labels and borders between neighboring areas are derived from the MPM (see Fig. B). White lines denote area boundaries, defined in individual subjects as phase reversals at or close to the upper vertical (dashed red), lower vertical (dashed blue), or horizontal (dashed green) meridians. Dashed black lines indicate borders based on eccentricity representations or the outline of hFEF. Note that because the borders are derived from the MPM, the dashed colored lines indicated the expected phase reversals, not phase reversals derived from the group-averaged phase maps themselves. Arrowheads in (B) indicate activity that is likely derived from the thalamus (). Arrowheads in (C) indicate the region that is likely the PreCC/IFS, previously reported by .