MRI scan parameters
All participants were scanned in the supine position on a 1.5T uMR560 MR scanner (United Imaging Healthcare, Shanghai, China) with a 12‐channel head coil specially designed for scalp acupuncture (AHC12). The sequences included axial T2WI, three‐dimensional T1‐weighted imaging (3D T1WI), and blood oxygen level‐dependent fMRI. The parameters were as follows: (1) T2WI: repetition time (TR)/echo time (TE) = 5000 ms/81.1 ms, flip angle = 150°, field of view = 200 × 230 mm, slice thickness/slice gap = 5 mm/1 mm, matrix = 331 × 448; (2) 3D T1WI; TR/TE = 10.4 ms/4.4 ms, flip angle = 15°, field of view = 256 × 220 mm, thickness = 1 mm, matrix = 192 × 256, and slices = 172; (3) fMRI in axial planes: TR/TE = 3000 ms/30 ms, flip angle = 90°, field of view = 225 mm × 225 mm, thickness = 3.5 mm, slice gap = 0 mm, matrix = 64 × 64, and slices = 37, scan time = 3 min and 30 s.