Accumulating evidence from fMRI studies suggest that functional connectivity (FC), a measure to elicit temporal synchrony between neural signals across specific brain regions [39], is an effective method not only to study the functional organization of a healthy brain [40,41,42] but also to understand neurocognitive impairments and psychopathology [43,44]. Recent studies have also demonstrated that AUD is associated with atypical FC in resting state networks [9,10,11,45,46,47,48], thus compelling its use in ML models for predicting AUD. Among the resting state networks, the Default Mode Network (DMN) is the most studied network and has been shown to play a central role in the intrinsic network properties and neural organization during spontaneous mental processes [39]. Atypical DMN connectivity has been reported in alcohol and other substance use (see, review by Zhang and Volkow [49]), and the connectivity changes have been primarily attributed to craving and relapse in chronic abusers of drugs [49]. Aberrations in the DMN were shown to be related to impaired self-awareness, negative emotions, and to ruminations related to addiction [49].
