Transcranial Direct Current Stimulation over the Posterior Parietal Cortex (PPC) Enhances Figural Fluency: Implications for Creative Cognition

Abstract

Creative cognition and figural fluency are two closely related concepts. Previous studies suggest different brain regions involved in figural fluency, creativity, and divergent thinking including frontal and parietal cortices. Furthermore, neural underpinning of the figural fluency is yet to be studied. This study aimes to investigate effects of modulation of cortical excitability in the right posterior parietal cortex (r-PPC) and left dorsolateral prefrontal cortex (l-DLPFC) on figural fluency using transcranial direct current stimulation (tDCS). Twenty neurologically unimpaired participants (mean age 27.55, SD = 5.11) received anodal r-PPC (P4), anodal l-DLPFC (F3), and sham tDCS (15 min, 1.5 mA) with 72-h interval between each stimulation condition. After 5 min of stimulation, participants underwent the Five-Point Test (FPT) which is a measure of figural fluency. Results showed that although participants produced more unique figures under both stimulation montages, they significantly produced more unique designs under anodal r-PPC tDCS compared to anodal l-DLPFC and sham tDCS. Findings imply that figural fluency is more dependent on the activation of the right posterior regions of parietal cortex, which is associated with spatial cognition, visual attention, cognitive flexibility, and creative cognition, but may partially benefit from activation of prefrontal regions too. tDCS has beneficial effects in enhancing figural fluency and potentially creative cognition as well as potential therapeutic effects in disorders suffering from impaired figural fluency.