Bifrontal tDCS applied to the dorsolateral prefrontal cortex in heavy drinkers: Influence on reward-triggered approach bias and alcohol consumption.

Even though the ventromedial neural network (reward pathway) has been well documented to be a mediator for increased craving, the prefrontal cortex is receiving ever more attention for craving monitoring. In the current study, we examined whether causal modulation of the prefrontal cortex, and its associated neural network, diminishes reward-triggered approach bias (due to increased cognitive control), alcohol craving and consumption. Using a double-blind within-subjects design in a subclinical group of forty-five heavy drinkers, a single sham controlled session of bilateral transcranial direct current stimulation (tDCS) was applied to the dorsolateral prefrontal cortex (DLPFC). Following real and sham tDCS placing the anode over the right and cathode over the left DLPFC, a rewarded Go/NoGo paradigm was administrated to provoke behavioral biases (irrespective of the task goal) After the cognitive paradigm, alcohol consumption was examined using a beer taste test. Bifrontal tDCS resulted in a reduced reward-triggered approach bias and reduced alcohol consumption, but not self-reported craving. Interestingly, reward-triggered approach bias and alcohol consumption were reliably associated in the sham condition, but not in the tDCS condition. Reward-trigged approach biases might be a cognitive mechanism associated with alcohol prone behavior, and the role of the prefrontal network may be significant.