fMRI Data Acquisition and Preprocessing

Six functional task runs were collected in the same session as the T1 MPRAGE. Functional runs were acquired with a T2*-weighted EPI sequence (TR = 2200 msec, TE = 50 msec, flip angle = 50°, matrix 64 × 64, FOV = 220 mm, voxel size = 3.44 × 3.44 × 3.91 mm). Twenty-eight axial slices oriented to the AC-PC line were acquired in ascending order to give whole-brain coverage. The first 10 volumes acquired for each functional scan were discarded to allow for magnetization preparation and stabilization. In-plane turbo inversion recovery images (TR = 2000 msec, TE = 11 msec, matrix = 256 × 256, FOV = 220, voxel size = 0.43 × 0.43 × 3.91 mm, 28 slices) were collected as an intermediate target for registration of MPRAGE and EPI images.

fMRI data were analyzed using SPM12 software. Functional images were corrected for differences in slice timing and were realigned to the first volume to correct for head movement. To spatially normalize functional images to the Montreal Neurological Institute (MNI) template, the in-plane and MPRAGE images were used as intermediates. Following normalization, images were resliced to voxel size 2 × 2 × 2 mm and were smoothed with an 8-mm FWHM isotropic Gaussian kernel and high-pass filtered (128 sec).