Dear FS experts,

I resampled PET images for multiple subjects I used mri_vol2surfe to move these images onto fsaverage, not I have for every subject lh.PET and rh.PET

How can I create the average of multiple surfaces. For example:

on the left hemisphere of every subject I have 

lh.PET.subject1.nii,gz, lh.PET.subject2.nii,gz, lh.PET.subject3.nii,gz, .... lh.PET.subjectN.nii,gz

How can I create the average of these surfaces?

Thanks for any help

John