Thank you for your quick answer!

Could you please explain to me where to find the “stack1.mgh” file? In which part of the longitudinal analysis stream is it created? I thought it would be part of the fsaverage/surf folder, but I did not find it there.

Looking into the individual BASE/surf folders I found the individual stack files after using “long_mris_slopes” tried to extract the individual values with

mri_segstats --i subject_01_BASE/surf/lh.long.thickness-stack.mgh --seg perm.th40.abs.sig.ocn.mgh --avgwf subject_01.dat --sum subject_01.dat --excludeid 0

However, I am running into the following error:

ERROR: dimension mismatch between input volume and seg

input 132211 1 1

seg 163842 1 1

Did I understand something wrong? Do you have any idea how to fix this problem?

Thank you in advance for your help!

Kind regards,

Franziska Mund

Yes, you can run something like
mri_segstats --i stack1.mgz --seg ocn.mgz --avgwf subject.vals1.dat --excludeid 0 --sum sum1.dat
where stack1.mgz is the stack of subjects in fsaverage space from time point 1
The output subject.val1.dat will have a row for each subject and a column for each cluster. The value will be the average value from that subject over the voxels in that cluster

On 7/31/2025 9:26 AM, Franziska Mund wrote:

        External Email - Use Caution

Dear FreeSurfer Developers,

we have a longitudinal study design with one group and ran a paired analysis in FreeSurfer V6 (as described here: https://surfer.nmr.mgh.harvard.edu/fswiki/PairedAnalysis). Afterwards we corrected for multiple comparisons (as described here: https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/MultipleComparisonsV6.0).

One cluster showed a significant change for cortical thickness and the average values of each subject were located in the “y.ocn.dat”.

However, we are now wondering how it is possible to get the individual pre- and post-values for that specific cluster for all subjects. Is there any method to do so?

Any assistance is very much appreciated!

Thanks in advance.

Best,

Franziska

Dr. Franziska Mund

Wissenschaftliche Mitarbeiterin

Sportmedizinisches Institut

Warburger Straße 100

33098 Paderborn

Raum SP.0.508

Telefon +49 5251 60-3187

Mail mund@sportmed.uni-paderborn.de

Web www.uni-paderborn.de
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