Fig. 1.

Summary of methods for obtaining structural (i.e. segmentation, cortical thickness) and functional (segmentation-based ROI mean activation and volume) measurements. The T1-weighted image is processed through FreeSurfer's recon-all command to obtain a thickness surface map and segmentation labels of anatomical regions. Thickness values were first converted into a 3D volume that follows the contours of the white matter surface, and then the ROIs were applied to get average thickness values within the IFG. For thickness, a combination of both white and gray matter segmentations for each ROI was used to ensure that all values in the white surface-based thickness ribbon were captured. FSL-processed activation maps were first registered to T1-weighted activation maps and then the ROIs were applied to the resultant transformed image to get average thickness and extent values within the IFG ROIs. Gray matter segmentations for each ROI were used to capture values on the cortical surface.