FIGURE 3.

Examples of a fallout (a) and surviving vertices (b). The trace lines of an original undistorted mid‐thickness surface and distorted one are shown as olive and blue lines, respectively. A cortical ribbon, a gray matter zone positioning between the undistorted white and pial surfaces (these trace lines are not shown), is denoted as yellow voxels. A target vertex on the undistorted mid‐thickness surface (magenta filled circle on the olive line) moves onto the distorted mid‐thickness surface (magenta filled square on the blue line), which is outside the cortical ribbon in (a), thus determined as a fallout. Meanwhile, in (b), the correspondent vertex is inside the ribbon. In this case, the nearest vertex on the undistorted mid‐thickness surface to the correspondent vertex is searched (green filled circle). A cortical distance between the target and searched vertices is measured on the undistorted mid‐thickness surface (green curved arrowed line along the olive line), while the Euclidean distance between them is shown with a magenta arrowed line.