Another limitation is that the OUD group had significantly higher mFD, education, and NU than the HC group. However, the mFD difference between groups was only 0.03 mm, and all subjects in both groups met the stringent motion criteria for inclusion in the analysis (Supplementary File) [28]. Furthermore, the effects of head motion on the fMRI signal had been corrected with the CompCor method and the ICAAROMA method, and ICA components with possible motion-related structured noise are regressed out during the dual regression procedure [31–33]. Despite all of these correction procedures and the very small difference in head motion between groups, it is crucial to rule out variations in head motion as driving group differences in functional connectivity, and if there are group differences in head motion, then investigators should perform a check whether motion is correlated with functional connectivity in their study [28]. In our sample, when conducting this check, there was no statistically significant correlation between mFD and functional connectivity in any of the 4 networks analyzed. Education and NU were also not statistically significantly related to the
