Temporal interference stimulation modulates verbal working memory: an EEG study on hemispheric lateralization and neural dynamics

Temporal interference stimulation (TIS) is a novel technique for neural modulation; however, its precise effects on verbal working memory (WM) and underlying neural mechanisms remain underexplored. This study employed electroencephalogram (EEG) to investigate the temporal dynamics of TIS-induced modulation, with a particular focus on hemispheric lateralization, an aspect often overlooked. Using a delayed recognition task, we categorized WM into high-load and low-load conditions and applied TIS to the left and right hemispheres with sham stimulation as a control. The results revealed a robust right-lateralized effect of TIS under high-load conditions, characterized by increased N200 amplitude and decreased P300 amplitude at the right parietal site post-stimulation, whereas no significant effects emerged under low-load conditions. This pattern of results contrasts sharply with the null effects in low-load conditions, highlighting the influence of TIS on verbal WM under high-load conditions. Furthermore, our study uncovered distinct activation patterns between the 2 hemispheres, suggesting a complex interplay between hemispheric lateralization and TIS-induced neural modulation. Supporting the attention-memory model, our results indicated that the right parietal TIS facilitates cognitive resource redistribution through attentional modulation. This study fills a critical gap in understanding the impact of TIS on verbal WM and provides novel insights into its cognitive enhancement potential.