Comparing the Effectiveness of Anodal HighDefinition-tDCS versus Bipolar tDCS Montages in Modulating Inhibitory Control: An Experimental Study

Transcranial Direct Current Stimulation (tDCS) have acquired a great relevance in the neuropsychology field over the last decades. Nowadays, various configurations improved its efficacy, such as the High Definition -tDCS (HD-tDCS) montage, which allows a more focus and precise modulation over cortical regions, leading potential advantages in rehabilitative programs and experimental settings. However, direct evidence comparing the efficacy of HD-tDCS to the conventional bipolar tDCS in modulating cognitive function remains limited. For this reason, the present study aims to compare the effectiveness of bipolar tDCS and HD-tDCS in modulating inhibitory control. Experimental procedure involved three sessions, with anodal stimulation (2 mA; 20 min) for both the active conditions (bipolar, HD-), and one sham condition. tDCS was applied to the right Inferior Frontal Gyrus (rIFG), a region implicated in inhibitory control, with robust evidence about its involvement in the Stop Signal Task (SST). In parallel, the Double Response Task (DRT) was used as a control condition to disentangle tDCS effects on non-inhibitory action updating from “pure” inhibitory control. Preliminary results reported no differences between the experimental conditions, contrary to prior literature. This discrepancy may be attributed to the intrinsic variability of tDCS, from parameter settings differences between protocols to the interindividual variability in response to stimulation. Keywords: bipolar tDCS; HD-tDCS; inhibitory control; rIFG; SST; DRT.