8 channel head coil for parallel imaging

MRI scans were conducted on a 3 Tesla General Electric MR 750 system with 50-mT/m gradients and an 8-channel head coil for parallel imaging (General Electric, Waukesha, Wisconsin, USA). T1-weighted structural scans were acquired using a 3D FSPGR BRAVO pulse sequence (TR = 7.58 ms; TE = 2.936 ms; flip angle = 12°; image matrix = 256 × 256; voxel size = 1 × 1 × 1 mm³; 206 contiguous axial slices). T2*-weighted functional scans were acquired using a SENSE spiral-in pulse sequence along the axial plane (TR = 2000 ms; TE = 30 ms; flip angle = 70°; image matrix = 64 × 128; voxel size = 3.8 × 3.8 × 3.8 mm³; 34 contiguous axial slices).
Preprocessing and statistical analysis of MRI data were performed using the Statistical Parametric Mapping 8 software (SPM8; Wellcome Trust Center for Neuroimaging). Functional images were spatially realigned to correct for head motion artifacts, coregistered to T1-weighted structural images, normalized to the Montreal Neurologic Institute (MNI) space using high-dimensional warping estimated from T1-weighted structural images implemented in the VBM8 toolbox (http://dbm.neuro.uni-jena.de/vbm), smoothed using a 4-mm full-width half-maximum (FWHM) Gaussian kernel, and temporally filtered using a 128-s high-pass filter. The first five images of each run were excluded to focus analysis on images acquired after the magnet achieved steady-state equilibrium.