2.4.2. VBM-local gyrification index analysis

The 3D T1W images were analyzed using the computational anatomy toolbox (CAT12) (http://dbm.neuro.uni-jena.de/cat/) program implemented in SPM12 (https://www.fil.ion.ucl.ac.uk/spm) running in MATLAB (version 2013a, MathWorks, Natick, MA, USA). The hemispheric surface was reconstructed via projection-based thickness (PBT) automatic reconstruction [9]. The GM, WM, and CSF were analyzed using the original T1W images. The GM images were normalized to an Institute of Neurology (MNI) template. The CAT12 was homogeneity-checked [6]. The GM, WM, and CSF volumes were summed. The GM volume was compared across groups, and voxel density analysis was performed. The indentation index is the ratio of absolute mean curvature of the outer brain surface to the outer surface excluding sulci [10]. Using a standard thalamic mask, the whole brain and 2 regions of interest (ROIs) were compared. All of the ROIs were analyzed simultaneously for the left and right hemispheres, and the automatic anatomical labeling (AAL) atlas revealed the affected brain regions [6].