[Freesurfer] Creating cached versions of Xhemi registrations

Dear FreeSurfer Users,

I'm using FreeSurfer version 6.0. I've processing subjects with recon-all and performed surface-based interhemispheric registration (via Xhemi at https://surfer.nmr.mgh.harvard.edu/fswiki/Xhemi).

I want to run a GLM on the subjects Area and Thickness from the differences (Left minus Right). When stacking subjects asymmetry maps, I wanted to use a "--cache-only".

The post at https://www.mail-archive.com/freesurfer@nmr.mgh.harvard.edu/msg27657.html seems to imply this requires running

recon-all -qcache -measure area -target fsaverage_sym -fwhm 10 -no-isrunning -s subjid -hemi lh

for area at FWHM = 10.

This would create files with the left hemisphere area registered to fsaverage_sym at smoothing FWHM = 10: $subjid/surf/lh.area.fwhm10.fsaverage_sym.mgh

However, how do I do this also for the xhemi registration? I.e. create a file like $subjid/xhemi/surf/lh.area.fwhm10.fsaverage_sym.mgh

Then, if I do this, can I stack the subjects using something like:

mris_preproc --target fsaverage_sym --hemi lh

--xhemi --paired-diff \ --srcsurfreg fsaverage_sym.sphere.reg \ --cache-in area.fwhm10.fsaverage_sym \ --out lh.lh-rh.area.sm10.mgh \ --s subj1 --s subj2 ...

Thank you.

Best, Chintan

mris_preproc --target fsaverage_sym --hemi lh --xhemi --paired-diff \

--srcsurfreg fsaverage_sym.sphere.reg \ --meas thickness \ --out lh.lh-rh.thickness.sm00.mgh \ --s subj1 --s subj2 ...