Transcutaneous auricular vagus nerve stimulation facilitates visuomotor association learning: Behavioral and electrophysiological evidence

Associating visual cues with appropriate motor responses is a fundamental adaptive skill. Transcutaneous auricular vagus nerve stimulation (taVNS) may enhance visuomotor association (VMA) learning, though its neural mechanisms remain unclear. Electroencephalogram (EEG), with its millisecond temporal resolution, offers unique advantages for elucidating the neurodynamic of VMA plasticity. This single-blind, sham-controlled, between-subjects study investigated whether taVNS facilitates VMA learning through behavioral and EEG analysis. Participants (each group N = 19) performed a VMA task (associating five oracle pictures with five keyboard keys) before and after 20-min active/sham taVNS. Behavioral results revealed that compared to the sham group, the active group exhibited shorter reaction time, higher response accuracy and larger learning curve integration, confirming the positive effect of taVNS on VMA learning. Neurophysiologically, taVNS reduced the P200 and P300 amplitudes, enhanced N170 negativity and attenuated error-related negativity. Cross-regional-frequency phase-amplitude coupling results demonstrated enhanced synchronization of frontal-parietal-occipital neural cross-frequency activity. Additionally, parietal-occipital θ, α, β band inter-trial phase coherence was enhanced in the active group. These findings demonstrate that taVNS enhances VMA acquisition through optimizing visual and error processing efficiency. This study establishes a neurophysiological basis for taVNS's cognitive enhancement potential, suggesting its utility in rehabilitative paradigms targeting associative learning deficits.