All MRI data were acquired on a Siemens Trio with a 12-channel Head Matrix Coil (Siemens AG). Head motion was reduced by the use of foam pads around the subjects' heads. During Not-X CPT performance ∼380 T2* weighted, BOLD-sensitive volumes were acquired for each “run,” using an echo-planar imaging pulse sequence with TR of 2400 ms, TE of 35 ms, FOV of 244 mm, matrix of 80 × 80, slice thickness of 3 mm, and a total of 40 slices, giving an in-plane resolution of 3 × 3 mm. Slices were positioned transversal along the A–P axis. Before each “run,” 2 spin echo sequences (TR = 2010 ms, TE = 35 ms, FOV = 244 mm, slice thickness = 3 mm, and matrix 80 × 80, giving an in-plane resolution of 3 × 3 mm) with opposite phase encoding (A–P and P–A) were acquired for correction of static magnetic field-induced distortion (Holland et al. 2010 (link)). For anatomical reference, a T1-weighted 3D MPRAGE volume was acquired (TR = 2300 ms, TE = 30 ms, FOV = 256 mm, slice thickness = 1.2 mm, and matrix 256 × 256, giving an in-plane resolution of 1 × 1 mm).