The Impact of Transcranial Photobiomodulation on the Bilateral Dorsolateral Prefrontal Cortex in Enhancing Convergent Thinking and Stroop Test

ABSTRACT Transcranial photobiomodulation (tPBM) has been employed for cognitive enhancement in healthy individuals. This study aimed to investigate the effects of tPBM applied bilaterally over the dorsolateral prefrontal cortex (DLPFC) on convergent thinking (CT), divergent thinking (DT), and the Stroop test. Additionally, we explored whether Stroop performance mediates the effect of tPBM on creativity. In this double‐blind, between‐subjects study, 56 healthy participants were randomly assigned to either the tPBM or sham group. tPBM was administered using near‐infrared light (810 nm, 40 Hz; 50% duty cycle) over the right and left DLPFC for 20 min. Creativity was assessed at baseline and during stimulation using the Unusual Uses (UU) and Picture Completion (PC) for DT, and the Remote Associates Test (RAT) for CT, and the Stroop test. ANCOVA, controlling for baseline scores, revealed that the tPBM group scored significantly higher than the sham group on the RAT ( F = 6.15, p = 0.016) and Stroop ( F = 4.89, p = 0.031). However, no significant differences were observed for DT. The findings suggest that tPBM may be effective in enhancing CT, but its effect does not appear to be mediated by improvements in Stroop performance. These results indicate that tPBM could be a promising tool for cognitive enhancement in the healthy population.