Midbrain-Driven Emotion and Reward Processing in Alcoholism

Abstract

Alcohol dependence is associated with impaired control over emotionally motivated actions, possibly associated with abnormalities in the frontoparietal executive control network and midbrain nodes of the reward network associated with automatic attention. To identify differences in the neural response to alcohol-related word stimuli, 26 chronic alcoholics (ALC) and 26 healthy controls (CTL) performed an alcohol-emotion Stroop Match-to-Sample task during functional MR imaging. Stroop contrasts were modeled for color-word incongruency (eg, word RED printed in green) and for alcohol (eg, BEER), positive (eg, HAPPY) and negative (eg, MAD) emotional word content relative to congruent word conditions (eg, word RED printed in red). During color-Stroop processing, ALC and CTL showed similar left dorsolateral prefrontal activation, and CTL, but not ALC, deactivated posterior cingulate cortex/cuneus. An interaction revealed a dissociation between alcohol-word and color-word Stroop processing: ALC activated midbrain and parahippocampal regions more than CTL when processing alcohol-word relative to color-word conditions. In ALC, the midbrain region was also invoked by negative emotional Stroop words thereby showing significant overlap of this midbrain activation for alcohol-related and negative emotional processing. Enhanced midbrain activation to alcohol-related words suggests neuroadaptation of dopaminergic midbrain systems. We speculate that such tuning is normally associated with behavioral conditioning to optimize responses but here contributed to automatic bias to alcohol-related stimuli.

Co-occurring Attention Deficit Hyperactivity Disorder symptoms in adults affected by heroin dependence: Patients characteristics and treatment needs

“…To this purpose, impaired reward processing in the prefrontal cortex has been found to be associated with persistent attention deficit hyperactivity disorder in the adult (Wetterling et al, 2015) and seems also to underlie substance use disorders vulnerability (Park et al, 2010; Müller-Oehring et al, 2013; Lee et al, 2013; Tanabe et al, 2007). Accordingly, frontal dysfunctions of impulse control, with disturbed activity mainly in ventrolateral and medial prefrontal regions, have been reported in both ADHD and SUD patients (Sebastian et al, 2014).…”

Perspectives on fronto-fugal circuitry from human imaging of alcohol use disorders

“…Highlighting the relevance of frontostriatal systems to behavioral regulation in AUD, abnormal connectivity (e.g., between the dorsolateral PFC and striatum) predicts impairments in learning (Park et al, 2010) and response inhibition (Courtney et al, 2013; Muller-Oehring et al, 2013; Schulte et al, 2012). Impaired functional connectivity may in fact be due to compromised anatomical integrity of corticostriatal fibers (Yeh et al, 2009).…”

The neural correlates of priming emotion and reward systems for conflict processing in alcoholics

“…Chronic alcoholism is associated with difficulty in exerting executive control of behavior when faced with choices involving reward and emotion (Müller-Oehring et al 2013). The rewarding effects of alcohol are transmitted via projections in the mesolimbic corticostriatal system that originates in midbrain structures (Berridge and Robinson 2003; Di Chiara 2002).…”

“…Further, we have found evidence for a role of midbrain-based reward systems to interact with frontoparietal executive control systems in ALC using Stroop Match-to-Sample task-activated fMRI probing executive control and automatic response functions arising from repetition learning (Schulte et al 2012). We accordingly devised an alcohol-emotion Stroop Match-to-Sample fMRI task (Müller-Oehring et al 2013) requiring inhibition of emotion and alcohol-related Stroop word content and found evidence for activation of midbrain-limbic reward and emotion systems to alcohol-related Stroop conflict while dlPFC executive control regions were less activated in ALC.…”