Non‐Invasive Brain Stimulation of the Ventromedial Prefrontal Cortex Improves Behavioral Inhibition by Enhancing the Processing Depth and Anticipation of Outcomes in a Gambling Task

Disordered gambling and other behavioral addictions are characterized by a lack of behavioral inhibition, such that patients repeatedly make disadvantageous decisions and fail to disengage from maladaptive behavior. Previous research has shown that behavioral addictions are associated with altered ventromedial prefrontal cortex (vmPFC) activity, making it an interesting target for neuromodulation. Using a gambling paradigm containing positive and negative expected value trials, we investigated decision-making and feedback processing while stimulating the vmPFC via transcranial direct current stimulation, and we recorded neural responses via EEG. We recorded behavioral and neural responses when the cue indicating reward probability and the outcome (gain/loss) were presented. At the behavioral level, interactions of stimulation by cue modulated gambling behavior, whereby we found different patterns for positive and negative expected value trials. We observed the respective interactions in the EEG data covering left dlPFC and parietal areas. The stimulation modulated the processing of outcomes depending on its probability in the behavioral and neural data. The behavioral results suggest improved gambling behavior after vmPFC excitation, especially when the risk of losing is high, visible in enhanced behavioral inhibition. This appears to be due to an enhanced anticipation based on reward probability and processing depth of outcomes. The neural results indicate that vmPFC excitation allows for a better ability to suppress high-risk decisions and a more accurate updating of gambling-related information. This makes excitatory vmPFC-tDCS promising as an additional treatment option for behavioral addictions.