In previous work using the same rs-fMRI images and NAcc seed-correlation maps as used in this paper, a multiple comparison corrected voxel-wise group analysis revealed significantly higher strength of RSS in LTAA vs. NSAC between the NAcc and the DLPFC and the superior frontal gyrus, and lower strength of RSS between the NAcc and the thalamus (both anterior and medical dorsal nuclei), the postcentral gyrus, and the inferior parietal lobule (Camchong et al., 2013b). The independent component for the seed-correlation map derived using parallel ICA also identified higher strength of RSS in the DLPFC and other frontal regions (notably the anterior cingulate and superior/inferior frontal regions) and lower strength of RSS in the thalamus and insula. The remarkable similarity in the results from such different analysis approaches gave us confidence that parallel ICA, which can be prone to model selection errors and overfitting, was decomposing the seed-correlation map into appropriate components. The additional regions discovered with parallel ICA, the higher synchrony with the anterior cingulate and lower synchrony with the insula, are also implicated in executive control and reward processing.
