Figure 1.

Example of sulcal variability and corresponding region‐of‐interest (ROI) boundaries in a case with (A) an “absent” paracingulate sulcus (PCS) and “continuous” superior rostral sulcus (SRS) and (B) a “present” PCS and “separate” SRS. Left column presents a representative sagittal slice through the T1‐weighted image with major sulci marked in yellow. Middle column presents the reconstructed white matter (above) and pial (below) surfaces, again with the major sulci marked in yellow. The Sulci on the white matter surfaces are represented by indentations or “crevasses,” whereas gyri are represented by protrusions, or “ridges.” Right column presents the same white and pial surfaces with the six ROIs overlaid on top. The yellow lines correspond to the posterior border of the dorsal region (posterior line), the border between the dorsal and rostral regions (anterior line), and the posterior border of the subcallosal region (middle line inferior to genu). Following Vogt et al. [1995], the PaC was located in the dorsal bank of the cingulate sulcus (CS) in “absent” cases, and extended from the CS to the PCS in “present” cases. Accordingly, note how the PaC ROIs are not visible from the pial surface in case A, but are easily visualized on the white matter surface. See text for more details.