Irregular Autonomic Modulation Predicts Risky Drinking and Altered Ventromedial Prefrontal Cortex Response to Stress in Alcohol Use Disorder.

AIMS: Autonomic dysfunction has been associated with risky drinking and alcohol use disorder (AUD). Although autonomic nervous system (ANS) activity has been attributed to the ventromedial prefrontal cortex (VmPFC)-limbic-striatal regions, the specific role of ANS disruption in AUD and its association with these regions remain unclear. Using functional magnetic resonance imaging (fMRI) and concurrent electrocardiogram (ECG), the current study examined neural correlates of ANS activity in AUD and its role in AUD pathology. METHODS: Demographically matched 20 AUD patients and 20 social drinkers (SD) completed an fMRI task involving repeated exposure to stress, alcohol-cue and neutral-relaxing images in a block design. Based on the known VmPFC-limbic-striatal functions involved in emotions, reward and the ANS, we performed a regions of interest (ROI) analysis to examine the associations between ANS activity and neural responses in the VmPFC, amygdala, and ventral striatum. RESULTS: Across conditions, AUD patients showed significantly higher levels of overall heart rate (HR) and approximate entropy (ApEn) compared to SD (Ps < 0.05). In all participants, increased HR was associated with greater drinking volume (P < 0.05). In addition, higher ApEn levels were associated with greater drinking volume (P < 0.05) and decreased right VmPFC response to stress (P < 0.05). DISCUSSION: Our findings demonstrate ANS disruption in AUD indexed by high overall HR and ApEn. The association between ApEn and rVmPFC response suggests that ApEn may play a role in modulating drinking via interactions with neural regions of emotion regulation. These findings provide insight into patterns of ANS disruption and their relevance to AUD pathology.

Limbic response to stress linking life trauma and hypothalamus-pituitary-adrenal axis function.

Trauma alters neuroendocrine responses to stress and increases vulnerability to stress-related disorders. Yet, relationships among trauma, stress-induced neural changes and hypothalamic-pituitary-adrenal (HPA) axis activity have not been determined. The present study used functional magnetic resonance imaging to investigate the impact of life trauma on basal cortisol levels and neural responses to acute stress in 73 healthy individuals during brief stress and neutral-relaxing imagery using a well-established, individualized imagery method. We hypothesized that trauma experience would have a negative impact on brain function, resulting in altered basal cortisol levels via dysregulated neural control over the HPA axis system. Results showed that higher life trauma exposure was significantly associated with lower basal cortisol levels. Neuroimaging results indicated that both higher life trauma and low morning cortisol levels were associated with increased response to acute stress in limbic-medial temporal lobe (MTL) regions including the amygdala and hippocampus. A mediation analysis showed that increased limbic-MTL response to stress mediated the relationship between life trauma and low cortisol levels. Findings revealed a significant impact of lifetime trauma on neural responses to acute stress and HPA axis activity. Life trauma may sensitize limbic-MTL regions and its related peripheral systems, which could compromise stress regulation and HPA axis function, and increase risk for negative stress-related health outcomes.