The details of image processing for the resting state fMRI are available in our previous study [63]. Briefly, the intra-subject inter-modality linear registration module [64] of the automatic registration toolbox (ART; www.nitrc.org/projects/art (accessed on 20 December 2019) was used to register the structural (MPRAGE) and functional MRI volumes. The brainwash program within the ART toolbox was used for skull-stripping the MPRAGE volumes. Motion detection and correction were performed using the 3dvolreg module of the AFNI software package [65]. Furthermore, the non-linear registration module of the ART [66] was used to correct for the geometric distortions of the fMRI images due to magnetic susceptibility differences in the head, particularly at brain/air interfaces. The skull-stripped MPRAGE images from all subjects were non-linearly registered to a study-specific population template using ART’s non-linear registration algorithm, which is one of the most accurate inter-subject registration methods available [67]. The population template was formed using an iterative method [68], and the motion-corrected fMRI time-series were detrended using PCA [69]. Finally, fMRI images from all subjects were normalized to a standard space.
