Dear experts,

I calculated vertex-wise standard deviation across multiple thickness (lh.thickness.fwhm10.fsaverage.mgh) and volume files (lh.volume.fwhm10.fsaverage.mgh) of one individual,    calculated from scans at different time points. I used the freesurfer library for R to calculate the sd in thickness and volume between scans and saved the sd in each vertex as a new mgh file (one for thickness and one for volume). 

I now need to parcellate (calculate the mean value in each parcel) my new mgh files containing the vertex-wise sd using the Desikan-Killiany Atlas and Destrieux Atlas as definitions for the parcels. What is the best way to approach this?

Thank you!