1000 Section - Enhancing Cognitive Performance through Bilateral Parietal tRNS: Behavioral and ERP Evidence from the PASAT

The Paced Auditory Serial Addition Task (PASAT) is a sensitive measure of cognitive control and information processing, widely applied in neurorehabilitation research. Transcranial random noise stimulation (tRNS) can enhance cortical excitability and cognitive performance. Given the inferior parietal cortex (IPC) plays a key role in attention and numerical processing, it represents a potential target for improving PASAT performance. However, the time course and neural mechanisms of IPC tRNS effects remain unclear. This study examined whether bilateral IPC tRNS enhances PASAT performance and modulates electrophysiological markers of cognitive control relevant to rehabilitation.

Design: The present study adopted a prospective, randomized, double-blind, crossover, placebo-controlled design. Thirty healthy adults were randomly assigned to both the tRNS and sham conditions. High-frequency tRNS (100–640 Hz, 2 mA) was applied over the bilateral IPC during PASAT performance. Behavioral accuracy and reaction time (RT) were measured across three sessions: Baseline, Online (during stimulation), and Offline (post-stimulation). Concurrent EEG was recorded to examine N2 and P3 components at fronto-central electrodes (Fz, FC1, FC2), which are associated with cognitive control and attentional processing.

Results: Behaviorally, the tRNS group demonstrated a significant improvement in accuracy during the Online phase compared with the sham group. RTs were significantly shorter in both the Online and Offline sessions relative to Baseline in the tRNS group. Moreover, ERP analyses revealed that both N2 and P3 amplitudes were markedly enhanced following stimulation in the tRNS group, whereas no significant changes were observed in the sham group.

Conclusion: tRNS applied over the IPC during PASAT improved behavioral performance and amplified electrophysiological markers of cognitive control and attention. The observed behavioral facilitation and ERP enhancement indicate that tRNS induces immediate and short-term aftereffects on cortical processing efficiency. These findings highlight the potential of tRNS as a promising neuromodulatory approach for cognitive rehabilitation.