Structural, DWI, and fMRI data for both timepoints were acquired on a 3T Siemens Trio Tim MRI scanner with a standard Siemens 32-channel phased array head coil. A whole-head, high-resolution T1-weighted multiecho MPRAGE33 (link) anatomical volume was acquired at each timepoint (acquisition parameters: TR = 2350 ms, TE = 1.64 ms, TI = 1400 ms, flip angle = 7°, FOV = 192 × 192, 176 slices, voxel resolution = 1.0 mm3, acceleration = 4). An online prospective motion correction algorithm reduced the effect of motion artifacts during the structural scan, and 10 selective reacquistion images were acquired and included to replace images that were affected by head motion34 (link).
Structural MRI data were processed using a semiautomated processing stream using the default parameters in FreeSurfer v5.2.035 (link),36 (link),37 ,38 (link); http://surfer.nmr.mgh.harvard.edu/), which includes motion and intensity correction, surface coregistration, spatial smoothing, subcortical segmentation, and cortical parcellation based on spherical template registration. The resulting cortical parcellation and subcortical segmentations were individually edited and reviewed for quality control and were used as seeds and targets for DWI tractography (below).