ORIGINAL ARTICLE Transcranial Direct Current Stimulation over the Posterior Parietal Cortex (PPC) Enhances Figural Fluency: Implications for Creative Cognition Elham Ghanavati 1,2 & Vahid Nejati 1,2,3 & Mohammad Ali Salehinejad 3,4 Received: 30 June 2017 /Accepted: 22 November 2017 # Springer International Publishing AG, part of Springer Nature 2017 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. Keywords Figural fluency . Creative cognition . Divergent thinking . Transcranial direct current stimulation . Posterior parietal cortex . Dorsolateral prefrontal cortex Introduction Fluency is defined as the ability to maximize unique response production while at the same time avoiding or minimizing response repetition (Ruff et al. 1994) and is generally divided into verbal and nonverbal categories. While verbal fluency is referred to the ability to generate and express words compat- ible with required criteria (Wysokiński et al. 2010), nonverbal fluency concerns with generating unique nonverbal responses and is usually measured by figural or design fluency (Ruff et al. 1986). Figural fluency tests are related to divergent thinking (Runco 1991) and creative cognition (Fink et al. 2010; Forthmann et al. 2016). These tests are usually used in tests of creativity and divergent thinking (Forthmann et al. 2016; Shamay-Tsoory et al. 2011), but some studies suggest that all forms of fluency, including verbal and nonverbal * Elham Ghanavati elhghanavati@gmail.com Vahid Nejati nejati@sbu.ac.ir Mohammad Ali Salehinejad Salehinejadmohammadali@gmail.com 1 Department of Psychology, Islamic Azad University, Science and Research Branch, Tehran, Iran 2 Department of Psychology and Educational Sciences, Shahid Behehsti University Tehran, Tehran, Iran 3 Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran 4 Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany Journal of Cognitive Enhancement https://doi.org/10.1007/s41465-017-0059-7