Résumé
This study aimed to investigate whether combined transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS) applied to the left dorsolateral prefrontal cortex (DLPFC) with the cathode over the inferior frontal gyrus (IFG) produce effects on creativity 1-day after being stimulated. In a double-blind, between-subjects design, 54 healthy participants were randomly assigned to either tDCS-tRNS or sham. The tDCS-tRNS group received 20 minutes of 1 mA tDCS with 1 mA (100-500 Hz) tRNS. Creativity was assessed before stimulation using the Unusual Uses (UU), Picture Completion (PC), Remote Associates Test (RAT), and nine-dot test (ND). One day later, participants completed parallel forms of the RAT, UU, and PC in a counterbalanced order, along with the ND. The tDCS-tRNS group showed significantly higher scores on the RAT one day post-stimulation compared to sham (p = .011,eta 2 p = .12). No significant differences were observed for UU or PC. Although the ND solution rate was nearly four times higher in the tDCS-tRNS group, it did not reach statistical significance. The total creativity score was significantly higher in tDCS-tRNS (p = .016, eta 2 p = .14). Combined tDCS-tRNS over the left prefrontal cortex may produce effects on convergent but not divergent thinking one day after being stimulated.