I've created a custom '.mgh' file containing values on the cortical surface using mri_vol2surf. I would like to compute some statistics on this surface in the aparc-areas computed by freesurfer. Can I then just use  mri_anatomical_stats with option -t specifying the custom mgh file as 'thickness' input? Or does mri_anatomical_stats something more complex than just averaging the values inside each region? 

Best,

Martijn