Hello Freesurfers

A bit new to the program, so I hope the following makes sense. We would like to do a bottom-up vertex-by-vertex analysis to see where functional activation correlates with thickness. We've done our functional analyses through SPM and can get those maps into tksurfer. Most of the tutorials and information I see has to do with, for example, defining a ROI based on functional data and extracting the thickness measures "under" that ROI. But this would be a little different

Does this make sense, and is this doable in freesurfer? If so, could someone point me to the relevant tutorial or commands?

I appreciate your help