Signa hd twinspeed scanner

The fMRI data were acquired on a 3T General Electric Signa HD × Twinspeed scanner (Milwaukee, Wisc.) fitted with a quadrature birdcage head coil: TR = 2000 ms, TE = 30 ms, FOV = 192 × 192 mm, voxel size = 3 × 3 × 5 mm, flip angle = 80°, number of time points = 135. T1-weighted structural data was acquired sagittally: TR = 7.312 ms, TE = 3.016 ms, FOV = 270 × 270 mm, matrix size = 256 × 256, slice thickness = 1.2 mm, flip angle = 11°.
Each participant’s fMRI images were first corrected for slice-timing and head movement with FSL [56 (link), 57 (link)]. Volumes in each subject that had framewise displacement (FD) >0.5 mm [57 (link)] were identified using fsl_motion_outliers and were subsequently regressed out in the first-level general linear model (GLM) in FSL [56 (link), 57 (link)]. A temporal high-pass filter at 128 s was applied and the fMRI data were smoothed by 8 mm full width at half-maximum kernel. One ASD participant had more than 30% volumes with FD > 0.5 mm and was removed from further analyses, giving us a final sample of 39 individuals.

All participants were scanned at the Centre for Neuroimaging Sciences, King’s College London, on a 3-T General Electric Signa HD × Twinspeed scanner (Milwaukee, Wisc.), fitted with a quadrature birdcage head coil. For the fMRI, we acquired T2*-weighted volumes (GNG = 260; SAT = 480) on non-adjacent slices (GNG = 37;SAT = 31) parallel to the anterior–posterior commissure. For GNG, imaging parameters were: TE = 30 ms, TR = 1.8 s, flip angle = 73°, slice thickness = 3.0 mm, in-plane voxel size = 3.75 mm², slice gap = 0.7 mm and matrix size = 64 × 64 voxels. For SAT they were: TE = 30 ms, TR = 1.5 s, flip angle = 68°, slice thickness = 3.0 mm, in-plane voxel size = 3.75 mm², slice gap = 1.4 mm, and matrix size = 64 × 64 voxels.
Also, a high-resolution gradient echo structural scan was sagittally acquired to be used during normalization of the fMRI data into Talairach space. Imaging parameters were: TE = 30 ms, TR = 3 s, flip angle = 90°, 43 slices, slice gap = 0.3 mm, slice thickness = 3.0 mm, matrix size = 128 × 128 voxels.