Preprocessing was completed in AFNI26 and involved the following: (1) volume registration, (2) despiking, (3) spatial normalization to Montreal Neurological Institute (MNI) space using a 12-parameter affine model, (4) reslicing all data to 3-mm isotropic voxels, and (5) spatial smoothing (8mm FWHM). Participant motion was estimated using AFNI’s enorm function (https://afni.nimh.nih.gov/pub/dist/doc/program_help/1d_tool.py.html), which is similar to framewise displacement.27 Displacement in millimeters for three directions and three rotations from one volume to the next were calculated and then a median value created for each participant.
