The effect of changing the balance between right and left dorsolateral prefrontal cortex on different creativity tasks: A transcranial random noise stimulation study

Transcranial random noise stimulation (tRNS) increases performance in some perceptual tasks. However, little is known about its effect on creativity. Although dorsolateral prefrontal cortex (DLPFC) has been postulated as an important cortical area related to creativity, the relative role of left and right DLPFC is still unclear. We aimed to compare the effect of anodal left/cathodal right (L + R-) and cathodal left/anodal right (L - R+) tRNS over the DLPFC. Eighty-four participants were randomly assigned to L + R-, L-R+ or sham group. Current was set at 2 mA (100-500 Hz) with a 1 mA direct current offset (20 min). Creativity was assessed before and during tRNS with the Remotes Associates Test (RAT), Unusual Uses (UU) and Picture Completion (PC) from Torrance Test of Creative Thinking, nine-dot problem and matchstick arithmetic problems. Bootstrapped analysis of covariance (under-stimulation scores controlling for baseline) showed that L + R- and L - R+ groups had higher scores than sham in UU whereas only L + R- improved in RAT compared to sham. The L - R+ group performed significantly better than L + R- and sham groups in PC, nine-dot problem and matchstick arithmetic problems. L + R- DLPFC may help verbal creative thinking whereas the L - R + seems to produce a "releasing effect" through insight problem solving and originality.