I have done two group thickness difference analysis based on whole brain. Now I want to do correlation analysis between specific ROI thickness and behavior score. I searched roi in the FS website, but I cannot distinguish the volume ROI and surface ROI very clearly. So I have some questions as below:

       1,As I get some clusters in the two group t-test,I want to use one of these clusters to correlate thickness with behavior score. How to generate this mask and how to use this mask in the mri_glmfit and mri_glmfit-sim?

       2,If I want to draw ROI manually or set ROI according previous studies, how to create this ROI mask.

        Any detailed information will be highly appreaciated.

       Thanks.

       All the best.

Rujing Zha