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

Abstract

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.