Frequency-specific transcranial neuromodulation of oscillatory alpha power alters and predicts human visuospatial attention performance

Transcranial alternating current stimulation (tACS) at 10Hz influences spatial attention. However, the neural mechanisms by which tACS modulates spatial attention remain poorly understood. Here, we applied high-definition tACS at the individual alpha frequency (IAF), two control frequencies (IAF+/-2Hz) and sham to the left posterior parietal cortex and measured its effects on visuospatial attention performance as well as alpha power (using electroencephalography, EEG). Our results revealed a leftward lateralization of alpha power relative to sham. At a high value of leftward alpha lateralization, we also observed a leftward attention bias, which differed from sham. Moreover, the magnitude of the alpha lateralization effect predicted the attention bias. These effects occurred for tACS at IAF but not for the control frequencies. This suggests that tACS operates through oscillatory interactions with ongoing brain rhythms in line with synchronization theory. Our results also highlight the importance of personalized stimulation protocols, especially in potential clinical settings.

10Hz经颅交流电刺激（Transcranial Alternating Current Stimulation, tACS）可影响空间注意。然而，tACS调控空间注意的神经机制仍未被充分阐明。本研究针对左侧后顶叶皮层，施加了基于个体α频率（Individual Alpha Frequency, IAF）的高清经颅交流电刺激，以及两个对照频率（IAF±2Hz）与假刺激，并通过脑电图（Electroencephalography, EEG）记录脑电α功率，同时测量其对视觉空间注意任务表现的影响。研究结果显示，相较于假刺激组，α功率呈现左侧偏侧化特征。当左侧α偏侧化程度较高时，我们还观察到与假刺激组存在显著差异的左侧注意偏向。此外，α偏侧化效应的强度可预测注意偏向的程度。上述效应仅在基于IAF的tACS干预中出现，对照频率组未观察到类似效应。这表明tACS通过与大脑自发振荡节律的振荡交互发挥作用，契合同步化理论。本研究结果同时凸显了个性化刺激方案的重要性，这一点在潜在的临床应用场景中尤为关键。