Drawing upon the above literature, we propose a model that integrates contemporary understanding of intrinsic network dynamics with evidence of alterations within and between these networks as a function of nicotine abstinence and administration, cue reactivity and/or drug urges. We hypothesize that during acute abstinence, the insula monitors salient interoceptive states, thus marking the presence of endogenous, withdrawal-related somatic, affective, and/or motivational events. The insula in turn interacts with DMN regions in the service of orienting attention to resolve this inner tumult and return the system to homeostasis, thereby shifting network dynamics and biasing processing towards the DMN and away from the ECN. Such a shift may underlie the cognitive impairments observed across various task domains during abstinence. Additionally, preoccupation with endogenous, withdrawal-related stimuli may hinder the capacity of the SN to engage in extrinsic performance monitoring, further contributing to cognitive deficits. Given the functional heterogeneity within insula, it remains for future research to identify those subregions most critically involved in such processes.
