(A) The mean deformation vectors, used to warp a surface vertex from its Native to its Anatomical (fsaverage-aligned) position and from its Anatomical to its Retinotopic position, are shown relative to each other. The wedges plotted beneath the mean arrows indicate ±1 standard deviation of the angle across subjects while the shaded regions at the end of the wedges indicate ±1 standard deviation of the lengths of the vectors. Note that because registration steps are always performed on a subject's inflated spherical hemispheres, these distances were calculated in terms of degrees of the cortical sphere and are not directly equivalent to mm of cortex. (B) The alignment of the V1-V3 region to the retinotopic prior increases the standard deviation of the surface curvature across subjects, suggesting that retinotopic alignment is not simply an improvement on FreeSurfer’s curvature-based alignment. Histograms show the probability density of the across-subject standard deviation of curvature values for all vertices in the V1-V3 region with a Bayesian-inferred eccentricity between 0 and 12°. (C) Bayesian-inferred iso-eccentricity lines and V1/V2/V3 boundaries plotted for all subjects simultaneously on the fsaverage spherical atlas. Lines are plotted with an opacity of 1/2 to visualize overlap. The left two plots and the right two plots share identical lines but have different colors. Iso-eccentricity lines are colored in magenta (1.5°), yellow (3°), and cyan (6°). Iso-angle lines are plotted in blue (upper vertical meridian), green (horizontal meridian), and red (lower vertical meridian).