Previous studies on nicotine use have focused in areas such as the insula (Droutman et al., 2015; Maria et al., 2015), known to reduce nicotine withdrawal when injured (Abdolahi et al., 2015), the default mode and executive control networks (Fedota and Stein, 2015; Sutherland et al., 2012). In our resting state analysis, the insula was involved with decreased connectivity with other regions in all three groups DRN, SAD and SMK, but a link with continuous measures of AUDIT and FTND could not be established. The involvement of the ECN was also very scarce and only comprised one parietal region. In contrast, the DMN connectivity (angular gyrus vs. precuneus) was found to be strongly affected by nicotine as group difference and FTND association both indicated a significant connectivity increment. The RSN pair PCC and postcentral gyrus also show connectivity increment linked to the DMN as smokers exhibited stronger anti-correlation. These results and the fact that smokers were abstinent for at least 3 hours before scanning seem concordant with the hypothesis that nicotine withdrawal might promote an enhancement in DMN functioning and
