Background: Activation of the anterior cingulate cortex (ACC) in a spatial working memory task has been associated with risk factors for alcohol use disorders such as low alcohol effects and positive alcohol expectations in adolescents. To transfer these results into adults, we used the same task in adults.
Methods: During functional magnetic resonance imaging, 12 light social, 7 heavy social, and 11 non-abstinent-dependent alcohol drinkers performed a spatial working memory task and completed measures of automatic alcohol-related thoughts and behavior (Obsessive–Compulsive Drinking Scale—OCDS), alcohol use of the last 90 days, and general intelligence.
Results: Behavioral performance in the spatial working memory task was not significantly different in all 3 groups. Controlling for differences in general intelligence alcohol-dependent participants showed a higher task-related activation of the dorsal ACC (dACC) in comparison with light and heavy social drinkers. Measures of the OCDS were positively correlated with the activation in the left hippocampus and right thalamus in all participants.
Conclusions: Our results support the findings of increased dACC activation during a spatial working memory task as a risk factor for alcohol dependence. Increased task-related activation in the dACC was only observed in alcohol-dependent participants and not in heavy social drinkers with comparable alcohol consumption. Furthermore, the absence of behavioral performance differences between groups as well as an association between dACC activation and working memory performance indicates subtle working memory deficits. Low capacity of working memory has been linked to more automatic and less self-regulated behavior in studies on natural reward processing. Therefore, additional neural activation during performance of the non-alcohol-related working memory task in participants with higher OCDS values in the left hippocampus and the right thalamus may be a consequence of decreased neural capacity because of distracting alcohol-related thoughts.