Figure 1.

(a–e) The definition of the CC on the MNI‐152 template: (a) the boundary is determined via an active contour; (b) lines are radiated from the centroid, and the midpoints of those that intersect the CC are calculated; (c) the shortest lines that cross the CC passing through the midpoints in b are found, and their midpoints are calculated; (d) the curve passing through the midpoints in c and extending to the CC boundary is divided into 25 equal length segments; the shortest lines crossing the CC at the ends of a segment define the subregion boundaries; (e) in color. The right part of the figure illustrates how the CC template (shown in the inset with the red border) is fit to individual subjects. The template T ₁ is registered to the subject's T ₁, and the transform applied to the template CC. The subject's b0 is registered to the subject's T ₁; the b0 to T ₁ transform is applied to the subject's radial diffusivity volume, thus overlaying the CC parcellation on the radial diffusivity volume as shown in the inset with the yellow border. The inverse of the b0 to T ₁ transform provides the mapping between the seed/target space and the diffusion space required by probtrackx.