Enhancing Creativity with Combined Transcranial Direct Current and Random Noise Stimulation of the Left Dorsolateral Prefrontal Cortex and Inferior Frontal Gyrus

Creativity is a fundamental human accomplishment from scientific advances to composing music. The left dorsolateral prefrontal cortex (DLPFC) and inferior frontal gyrus (IFG) are important metacontrol hubs in flexibility and persistence brain states, respectively. Those hubs are related to divergent thinking, insight problem-solving, and convergent thinking. In this double-blind, between-subjects study, 81 healthy participants were randomly assigned to one of three groups (n = 27) that received a combined transcranial direct current stimulation-transcranial random noise stimulation (tDCS-tRNS) protocol with the anode over the left DLPFC and cathode over the left IFG (+DLPFC-IFG), the opposite montage (-DLPFC+IFG), and a sham group (+DLPFC-IFG). Both active tDCS-tRNS groups received 20 min of 1 mA tDCS with 1 mA (100-500 Hz) tRNS. Creativity was assessed before (baseline) and during stimulation with the Unusual Uses, Picture Completion (PC), Remote Association test (RAT), Matchstick Arithmetic (MA), and Nine-dot (ND) problems. Only the +DLPFC-IFG group had significantly higher scores compared with sham in the RAT (p = 0.009), PC fluency (p = 0.018), PC originality (p = 0.007), ND (p = 0.007), and MA (p = 0.032). Overall, -DLPFC+IFG had greater scores in all creativity tests compared with sham. Implications from the metacontrol theory are discussed.