Mr750 3.0 t

Thirty‐two healthy rhesus macaques used in this study were obtained from the University of Wisconsin‐Madison dataset (Young et al. 2017 (link)). Each subject has four or five longitudinal brain MRI scans (GE MR750 3.0 T) at scheduled intervals, resulting in a total of 156 scans (scanning schedule in Figure S1). The parameters of T1‐weighted MRI are as follows: TI = 450 ms, TR = 8.684 ms, TE = 3.652 ms, FOV = 140 × 140 mm², flip angle = 12 deg, thickness = 0.8 mm, gap = −0.4 mm, 80% field‐of‐view in phase encoding direction, bandwidth = 31.25 kHz, 2 averages, total time = 10:46 min, acquisition matrix = 256 × 256 and voxel size = 0.55 × 0.55 × 0.8 mm³. The parameters of diffusion MRI are as follows: TR = 8000 ms, TE = 65.7 ms, FOV = 16.7 mm, matrix = 128 × 128, slice thickness = 2.6 mm, with 1.3 mm slice overlap (resolution 1.3 × 1.3 × 2.6 mm³), up‐sampled to a voxel dimension on the scanner of 0.65 × 0.65 × 1.3 mm³, 120 gradient directions with b = 1000s/mm² and 10 images with b = 0 s/mm².

fMRI experiments were carried out on a General Electric Discovery MR 750 3.0 T using a 32-channel head coil with subjects lying supine. Initial localizer images were acquired in three planes as a reference for slice positioning for subsequent fMRI studies. A standard whole-brain gradient echo planar imaging sequence was used for the functional scans (repetition time =3,000 ms; echo time =30 ms; 160 volumes field of view =240×240 mm², matrix =128×128, voxel size =1.8×1.8×3.6 mm³, acquisition time =8 minutes). A high-resolution volumetric three-dimensional (3D) T1-weighted acquisition was performed, for anatomical overlay of activation, in the same session as the functional scans: 3D brain volume imaging (repetition time =9.96 ms, echo time =4.1 ms, inversion time =400 ms, field of view =240×240 mm², matrix =512×512, voxel size =1×1×1.2 mm³, acquisition time =3 minutes 22 seconds). To achieve synchronization, the trigger output of the scanner was used to initialize the fMRI paradigm and triggers from contact heat-evoked potential stimulation and the scanner were recorded together. fMRI sequences were assessed in the following order: anatomical scout, 3D brain volume, fMRI BOLD sequence echo planar imaging (thermal stimulation).