As studies have shown that aging has an impact on functional connectivity (Andrews-Hanna et al., 2007, Damoiseaux et al., 2008, Tomasi and Volkow, 2012, Allen et al., 2011), we first compared an age-matched subset of ALC subjects with a group of HC to examine connectivity differences associated with problematic alcohol use. We expected that the ALC cases would have reduced resting state synchrony within ECNs implicated in addiction, but also tested whether differences compared to controls might be found globally within all ICNs. We also posited that reduced within-network functional connectivity in the ECNs, may be the neurobiological link between the neurotoxic effects of chronic alcohol exposure and problem alcohol use, having a mediating role on this relationship. To test this hypothesis, we used a structural equation model to test the indirect effect of alcohol exposure on problem alcohol use via network connectivity strength.
