Relationship between carotid intima‐media thickness (cIMT) and dual‐system imbalance in tobacco dependence: An rs‐fMRI research

BACKGROUND AND PURPOSE: According to the classic cognitive behavioral theory proposes, dysfunctional goal‐directed and habit control systems are considered central to the pathogenesis of dependent behavior and impair recovery from addictions. The functional connectivity (FC) of the brain circuits for goal‐directed or habitual behavior has not been clearly reported in tobacco‐dependent groups. Smoking is one of the factors in the formation of atherosclerosis. Studies have shown that the thickness of carotid intima‐media (cIMT) is associated with attention‐executive‐psychomotor functioning. Therefore, we hypothesized whether cIMT in tobacco‐dependent individuals is associated with changes in the FC of the dual‐system network. METHODS: A total of 29 male tobacco‐dependent subjects (tobacco‐dependent group) (mean age: 64.20 years, standard deviation [SD]: 4.81 years) underwent resting‐state functional magnetic resonance imaging (rs‐fMRI). Exactly 28 male nonsmokers (control group) (mean age: 61.95 years, SD: 5.52 years) were also recruited to undergo rs‐fMRI. We used the dorsolateral striatum (putamen) and dorsomedial striatum (caudate) as regions of interest for whole‐brain resting‐state connectivity to construct habitual and goal‐directed brain networks, respectively. In addition, all participants were evaluated by carotid artery ultrasound to obtain the cIMT values. Then, we compared the dual‐system brain networks between the tobacco dependence and control groups and the relationship between cIMT and imbalance of dual‐system brain networks in tobacco dependence. RESULTS: The results showed a reduction in the connection between the caudate and precuneus and an increased connection between the putamen and prefrontal cortex; and supplementary motor area. The bilateral connectivity between the caudate and inferior frontal gyrus showed a significant negative correlation with the cIMT, and no positive correlation was observed with cIMT in the brain region that connects to the caudate. However, for the putamen, increased connectivity with the inferior temporal and medial frontal gyri was strongly associated with a high cIMT. CONCLUSIONS: The results indicate that the formation of tobacco dependence behavior is related to changes in the dual‐system brain network. Carotid sclerosis is associated with the weakening of the goal‐directed network and enhancement of the habit network in tobacco dependence. This finding suggests that tobacco dependence behavior and clinical vascular diseases are related to changes in brain functional networks.