Anodal tDCS over right posterior parietal cortex reduces inter-vehicle distance variability: A driving simulator study

Abstract

Driving is a complex task requiring the integration of multiple cognitive functions and coordinated neural activity. Prior studies suggest that anodal transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex (DLPFC) can enhance driving performance, likely due to the DLPFC's role in executive functions. In addition to the DLPFC, the posterior parietal cortex (PPC)—involved in integrating sensory, cognitive, and motor signals—may also contribute to driving behavior. This study investigated the effects of anodal tDCS over the DLPFC and PPC on simulated driving performance. Participants completed a follow-the-lead-car task before and after stimulation, with performance measured using brake reaction time and its standard deviation, standard deviation of lateral position, percentage of speed limit violations, inter-vehicle distance, and the variability (i.e., root mean square) of inter-vehicle distance. We hypothesized that stimulation of either region would improve driving behavior. Results showed that anodal tDCS over the PPC significantly reduced the variability of inter-vehicle distance, suggesting enhanced driving stability. This effect likely reflects the PPC's involvement in spatial attention and motor integration—key processes for maintaining stable following distance. No significant improvements were observed in other performance metrics or following DLPFC stimulation. Overall, this is the first brain stimulation study that connects PPC with driving behavior, and highlights the potential of PPC as a neuromodulatory target to improve driving performance.