Thank you for the information. I've attached a picture here of the pb0*volreg volume overlayed on the anat_final. Just to make sure I understand, does this mean that during the 3dTproject step that all voxels outside of the anat_final space (non-brain; yellow and blue voxels) are set to 0 which is why such a high number of voxels (51,787) have a constant timeseries?