Fig. 2.

Three-dimensional reconstruction of the anterior limb of the internal capsule. The anterior limb of the internal capsule (ALIC) was traced on five proportionally spaced dorsal-to-ventral slices, yielding ALIC area at the five slice levels. ALIC volume was calculated for four dorsal-to-ventral segments of the ALIC based the areas of consecutive slices and distances between them. Panels A and B show the three-dimensional reconstruction which represent ALIC volume between and including the most dorsal and most ventral slices. Panel C shows the five manually-traced slices in red and the four dorsal to ventral contiguous volume segments. In order to examine group differences in the number of fiber tracts that extend from the ALIC to specific DLPFC Brodmann areas (BAs; BA10 and BA45), we used our cortical Brodmann-area program based on a coronal atlas composed of 33 axial maps of BAs from a microscopic examination of the entire hemisphere of a post-mortem brain. Our earlier use of the Perry atlas (Perry et al., 1991) including published illustrations of the maps has been described in detail elsewhere (e.g., Mitelman et al., 2005). This enabled us to count the number of fiber tracts originating from the five slice levels of the ALIC and extending to the two BA ROIs within the DLPFC. Briefly, we followed the atlas of Mori et al. (2005) and our published fiber-tractography methods which use a multiple-ROI selection technique (Buchsbaum et al., 2006c) beginning with every pixel in the internal capsule at each slice level. As in our prior study, the criterion for continuing the path to the respective BAs was an absolute anisoptropy value of 0.2 (this value is similar to that used in a recent tractography study by Oh et al., 2009), interpolated steps of 0.3 mm and a change of less than 30° from voxel to voxel.