Figure 4.

Comparison of stereological methods and voxel‐based morphometry for measurement of insular cortex volume. A–C: Stereology in conjunction with point counting used to estimate the volume of the insular cortices in a randomly selected individual. A: Point counting within the left and right insula is highlighted in yellow. B: Magnification of point counting within the left insula. C: Magnification of the left insula without the projected points for anatomical clarity. D: Correlation between insular volumes as quantified by stereology and by ROI‐VBM analysis (P < 0.001). E, F: Partial correlation plots (after correction for age and gender) of both insular measures with the digit span difference score (P < 0.05). Note that smaller difference scores indicate better executive performance. GM, gray matter; VBM, voxel‐based morphometry. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]