High-Resolution MRI and Resting-State fMRI Protocol

Magnetic resonance imaging (MRI) data were collected on a Siemens Magnetom Verio 3 Tesla scanner. A structural image was acquired using an MP2RAGE sequence (TR = 5000 ms, TE = 2.92 ms, TI1 = 700 ms, TI2 = 2500 ms, flip angle 1 = 4°, flip angle 2 = 5°, voxel size = 1.0 mm isotropic, duration = 8.22 min; Marques et al. 2010 (link)). Four resting-state functional MRI scans were acquired using a multiband EPI sequence (TR = 1400 ms, TE = 39.4 ms, flip angle = 69°, multiband acceleration factor = 4, voxel size = 2.3 mm isotropic, 64 slices, 657 volumes, duration = 15.30 min; Feinberg et al. 2010 (link); Moeller et al. 2010 (link)). Sequences were identical across runs with the exception of alternating phase encoding and slice orientation (AC–PC axis and aligned to orbitofrontal cortex) to vary the spatial distribution of signal loss across runs. During resting-state scans, participants were instructed to fixate on a crosshair. Field maps (TR = 680 ms, TE1 = 5.19 ms, TE2 = 7.65 ms, flip angle = 60°, voxel size = 2.3 mm isotropic, 64 slices) were obtained separately for each resting-state run to correct for magnetic field inhomogeneities.