Dear gPPI experts,

I have been trying to apply gPPI analysis to fMRI data processed by freesurfer and had two questions. It'd extremely helpful if you could give me your advice.

First, I was wondering how to make VOI files for gPPI based on .label and aseq.mgz files made by freesurfer. Is there any script for this purpose included in gPPI? Alternatively, is it possible to make such script by myself by using freesurfer-matlab interface scripts (like MRIread.m)?

Second, is there any script or pipeline to transform results obtained by the gPPI analysis to a freesurfer format so that I can perform statistics on freesurfer? I wondered if con.img made by gPPI corresponds to ces.nii on freesurfer. But if it is correct, I am not sure how to transform con.img to ces.nii.

Thank you very much for your help in advance!

Best,
Kaz

Hi Kazuhisa,

(1) I believe that converting the label and aseg files to nifti files should work. Just check that the nifti masks line up with the fsfast nifti functional volumes. As long as they are aligned, everything should work.

(2) Yes. ces.nii and con_####.img are the same. The con_*img can be used to perform statistics in freesurfer at the group the level.

Best,
Donald
Originally posted by Kazuhisa Shibata:

Dear Donald.

Thank you very much for the kind reply!

Got it. I will try this method! Just to confirm, this method should work even if functional data is made from cortex data which consists of N by 1 vector, as long as functional and VOI data are aligned in the same space (N by 1, in this case). I can imagine that volume data (X by Y by Z matrix) should work with this method.

Got it! I also try this!

Best,
Kaz