MRI acquisition
Data were acquired on a GE Signa HDx 3T system (General Electric, Milwaukee, Wisconsin) with an 8-channel head coil at the Centre for Neuroimaging Sciences, King’s College London. Functional T2*-weighted data comprised 39 interleaved slices acquired with a gradient EPI sequence bottom-to-top over 186 volumes depicting BOLD contrast covering the whole brain (TE = 30ms, TR = 2s, flip angle = 75°, in-plane voxel size = 3.75mm, slice thickness = 3.5mm, slice gap = 0.5mm). Whole-head structural image was acquired at the beginning of each scanning session using an MPRAGE protocol using parameters based on ADNI (TE = 2.85ms, TR = 6.99s, flip angle = 8°, in-plane voxel size = 1.02mm, 166 slices, slice thickness = 1.2mm, slice gap = 1.2mm).