FIGURE 5.

Generation of alpha surface for the calculation of sulcal depth. First, the 3D surface meshes reconstructed from the MR images using Freesurfer are smoothed and decimated. Secondly, the alpha surface is generated from the point cloud of the pial surface mesh (inset image shows the effect of alpha parameter). Finally, the outer alpha surface is isometrically shrunken to generate a midcortical surface