Hi FS experts and others, 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