thanks, I get now why it wasn't working earlier. I used the the MNI152_T1_2009c template with @auto_tlrc, but when using 3dROIstats later to get the beta coefficient for each voxel/node of the Schaefer_17N_400, I see a message in the terminal saying that my dataset has 8530021 voxels/nodes while the mask has 16777216. am I using the wrong template? thanks