We applied group independent component analysis (GICA) to the resting data using MELODIC (FMRIB Analysis Group, Oxford University).34,35 The preprocessed data in Talairach space from both sessions were submitted to MELODIC using the command-line tool with the component number set at 20 and the decomposition approach set as temporal concatenation. The GICA spatial maps were converted to z score maps and then thresholded via a mixture model fit to identify voxels contributing to each independent component.35 The SN, DMN, and ECN were identified by visual inspection of the thresholded GICA maps.15,17 The similarity in the spatial extent between the identified networks and previously published results34 was assessed using spatial cross-correlation. Spatial cross-correlation of the SN, ECN, and DMN (transformed to the Montreal Neurological Institute space) with maps described by Beckmann et al34 show that the identified ECNs are consistent with their frontoparietal network, whereas our SN is spatially consistent with their ECN.
