OA images were acquired on a 3T General Electric Excite MR system with an 8-channel phase-array head coil (General Electric Medical System, Milwaukee, WI, USA). A high-resolution anatomical SPGR image was acquired sagittally (TR = 8 ms, TE = 3 ms, flip angle = 12°, 1 mm3 voxels, FOV 240 mm, matrix interpolated to 256x256, slice thickness 1mm, 176 slices, bandwidth 31.25, acquisition time 7 minutes and 19 seconds). Functional imaging was collected in the axial plane using T2-weighted gradient echo imaging (156 repetitions, repetition time = 3000 ms, echo time = 30 ms, flip angle = 90°, field of view = 240 mm, 32 continuous 3.8 mm slices, matrix 64 × 64, in-plane resolution = 3.75 mm × 3.75 mm, total time 7 minutes 48 seconds). EPIs were unwarped with two field map acquisitions (each 1 minute and 8 seconds acquisition time; TR: 1000 ms, flip angle 60, FOV 240 mm, 32 contiguous axial slices each 3.8 mm thick, matrix 64 × 64, echo times 3.2 and 5.5 ms). Both groups completed the same SWM task (Figure 2), as previously described in detail (54).
