fslmerge -t subjects.nii subject1.nii subject2.nii subject3.nii fslmaths subjects.nii -Tmean mean_subject.nii Or something like that -- there's more than one way. Obviously, you will probably want to resample each subject into the same stereotactic space first. On Tuesday, November 29, 2011 22:34:49 you wrote: > Hello, > > I'm trying to average across 10 subjects' brains, but not sure how to go > about doing that. Any help will be greatly appreciated. > > Thanks, > Amy