Hi,

I think I have solved it myself, here's how:

Right:

mris_apply_reg --src data_on_fsavgsym_hemi-R.gii \
--trg data_native_rh.mgh \
--streg \
/usr/local/freesurfer/8.0.0/subjects/fsaverage_sym/surf/rh.sphere.reg \ ${freesurfer_dir}/xhemi/surf/lh.fsaverage_sym.sphere.reg

Left:

mris_apply_reg --src data_on_fsavgsym_hemi-L.gii \
--trg data_native_lh.mgh \
--streg \
/usr/local/freesurfer/8.0.0/subjects/fsaverage_sym/surf/lh.sphere.reg \
${freesurfer_dir}/surf/lh.fsaverage_sym.sphere.reg

Thanks,

Best,

Felix

From: Zahnert, Felix <fzahnert@mgh.harvard.edu>
Sent: Monday, June 2, 2025 12:31 PM
To: freesurfer@nmr.mgh.harvard.edu <freesurfer@nmr.mgh.harvard.edu>
Subject: [Freesurfer] register from fsaverage_sym back to native rh

Dear Freesurfer experts,

I would like to register surface data (an 'overlay' file) from fsaverage_sym space back to the subject's native rh.white surface.

This seemed to work fine for the lh data using:

mri_surf2surf --srcsubject fsaverage_sym --trgsubject fs8 --hemi lh --sval mysurfacedata_lh.gii --tval mysurfacedata_lh_native.mgh

However, I am struggling to do this for the right hemisphere.

Do you have any recommendations?

Thank you in advance,

Best,

Felix