were registered with the Open Science Framework (OSF) prior to any data analysis in this study [24]. The present study also compared post-hoc the functional connectivity of OUD subjects with different levels of OUD severity. To investigate the effects of heterogeneity of our OUD sample, we also performed post-hoc analyses of functional connectivity of OUD with urine drug screens positive for buprenorphine or methadone compared to OUD with urine drug screens positive only for illicit opioids. Also, to investigate the effects of heterogeneity, we examined the relationship between functional connectivity and time since last opioid use in the OUD subjects. Given our relatively small sample size (50 subjects total; 25 subjects per group), our results should be treated as preliminary for hypothesis generation, and replication will be needed in future studies.
