Effects of transcranial direct-current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) during a mixed-gambling risky decision-making task.

Previous studies have led to hypothesizing that right DLPFC activity is related to risk propensity, but the generality of this relationship remains unclear. Here, we experimentally modulated DLPFC activity in 47 healthy, female volunteers during a risky decision-making task, where monetary gambles defined by potential win, loss, and outcome probability were evaluated in the absence of feedback and uncertainty. Three participant groups, receiving left anodal/right cathodal, right anodal/left cathodal, and sham tDCS, were compared. Overall, participants performed the task well above chance level and were significantly risk averse, but tDCS did not affect task performance or risk propensity. However, right anodal/left cathodal tDCS significantly elevated response confidence, independently of accept/reject response. Our results suggest that the relationship between DLPFC activity and risk propensity may not be universally valid for all task types and requires further characterization. Enhancing right and attenuating left DLPFC activity boosts subjective confidence, with potential implications for understanding pathological gambling.