Modulatory effect of non-invasive prefrontal brain stimulation on risk-taking behaviours in humans: preliminary insight on the influence of personality traits

We investigated the modulatory effects of cathodal High-Definition transcranial Direct Current Stimulation (HD-tDCS) on the left dorsolateral prefrontal cortex (DLPFC) and the left ventrolateral prefrontal cortex (VLPFC) on risk-taking. Methods Thirty-four healthy adults underwent 3 independent cathodal HD-tDCS interventions (DLPFC, VLPFC, sham) delivered in counterbalanced order during the performance of the balloon analogue risk task (autoBART). Participants were clustered post-hoc in 3 separate personality profiles according to the HEXACO-60 and the Dark Triad dirty dozen and we reanalysed the data. Results Dorsal prefrontal cathodal HD-tDCS significantly modulated autoBART performance rendering participants less prone to risk-taking (i.e., more conservative) under left DLPFC HD-tDCS compared to left VLPFC or sham stimulation. The re-analysis of the same dataset, taking into consideration personality traits, suggested specific effects in impulsive-disinhibited and normative participants for DLPFC and VLPFC stimulation, respectively. Specifically, we saw that participants classified as impulsive-disinhibited were more affected by HD-tDCS left DLPFC stimulation than other profiles. Conclusions Both, dorsal and ventral prefrontal active HD-tDCS decrease risk-taking behaviour compared to sham stimulation. Importantly, such effects are likely influenced by personality traits (impulsive disinhibited vs normative) exhibited by the participants. Highlights We investigated the effect of dorsal and ventral prefrontal HD-tDCS on risk-taking. We considered post-hoc, the influence of individual personality differences. Dorsal and ventral Prefrontal cathodal HD-tDCS decreased risk-taking behaviour. Left cathodal DLPFC HD-tDCS decreased risk propensity in impulsive-disinhibited participants. Left cathodal VLPFC HD-tDCS decreased risk propensity in normative personality participants.