Dear Sir,
I get the correlation result between two condition  of the functional data by using AFNI( I do not know how to do correlation by using freesurfer).
And then I use the bbregister to aline the correlation result (produce by Afni) to the anatomical result produced by using freesurfer(recon-all).
Next I using mri_vol2surf to aline the each one's  functional result to the  fsaverage offer by freesurfer.
My question is : I have two group of subjects. I want to get  the correlation different between them? What should I do next by using freesurfer?  I want to know how to calculate the correlation between two group by using freesurfer based on the surface-based analysis?
Thanks very much!
Linda