Cravings for food, cocaine, and nicotine are also related to middle insular function.111–113 Tobacco smokers with damage to the insula (but not control smokers with extra non-insular lesions) were able to stop smoking easily and without experiencing cravings or relapse.114 The insula appears to have an interoceptive function that integrates autonomic and visceral information with emotion and motivation, thus providing conscious awareness of these urges.54 Brain lesion studies suggest that the ventromedial prefrontal cortex and insula are necessary components of the distributed circuits that support both emotional115 and moral116 decision making. Consistent with this hypothesis, imaging studies have reported differential activation of the insula during craving, possibly reflecting interoceptive cues and hypothesised to involve CRF activation (table 2, circuit 18).54,117,118 Accordingly, the reactivity of this brain region has been suggested to serve as a biomarker to help predict relapse.119
