Radecke Jan-Ole, Fiene Marina, Misselhorn Jonas, Herrmann Christoph S, Engel Andreas K, Wolters Carsten H, Schneider Till R
Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
Brain Stimul. 2023 Jul-Aug;16(4):1047-1061. doi: 10.1016/j.brs.2023.06.013. Epub 2023 Jun 21.
Covert visuo-spatial attention is marked by the anticipatory lateralization of neuronal alpha activity in the posterior parietal cortex. Previous applications of transcranial alternating current stimulation (tACS) at the alpha frequency, however, were inconclusive regarding the causal contribution of oscillatory activity during visuo-spatial attention.
Attentional shifts of behavior and electroencephalography (EEG) after-effects were assessed in a cued visuo-spatial attention paradigm. We hypothesized that parietal alpha-tACS shifts attention relative to the ipsilateral visual hemifield. Furthermore, we assumed that modulations of behavior and neurophysiology are related to individual electric field simulations.
We applied personalized tACS at alpha and gamma frequencies to elucidate the role of oscillatory neuronal activity for visuo-spatial attention. Personalized tACS montages were algorithmically optimized to target individual left and right parietal regions that were defined by an EEG localizer.
Behavioral performance in the left hemifield was specifically increased by alpha-tACS compared to gamma-tACS targeting the left parietal cortex. This hemisphere-specific effect was observed despite the symmetry of simulated electric fields. In addition, visual event-related potential (ERP) amplitudes showed a reduced lateralization over posterior sites induced by left alpha-tACS. Neuronal sources of this effect were localized in the left premotor cortex. Interestingly, accuracy modulations induced by left parietal alpha-tACS were directly related to electric field magnitudes in the left premotor cortex.
Overall, results corroborate the notion that alpha lateralization plays a causal role in covert visuo-spatial attention and indicate an increased susceptibility of parietal and premotor brain regions of the left dorsal attention network to subtle tACS-neuromodulation.
隐蔽的视觉空间注意以顶叶后皮质神经元α活动的预期性偏侧化为特征。然而，以往在α频率下进行经颅交流电刺激（tACS）的应用，在视觉空间注意过程中振荡活动的因果作用方面尚无定论。
在一个线索化视觉空间注意范式中评估行为和脑电图（EEG）后效应的注意转移。我们假设顶叶α-tACS相对于同侧视觉半视野转移注意力。此外，我们认为行为和神经生理学的调制与个体电场模拟有关。
我们应用个性化的α和γ频率tACS来阐明振荡神经元活动在视觉空间注意中的作用。个性化tACS蒙太奇通过算法优化，以靶向由EEG定位器定义的个体左右顶叶区域。
与靶向左顶叶皮质的γ-tACS相比，α-tACS特异性地提高了左半视野的行为表现。尽管模拟电场对称，但仍观察到这种半球特异性效应。此外，视觉事件相关电位（ERP）振幅显示，由左α-tACS诱导的后部位的偏侧化减少。这种效应的神经元源位于左运动前皮质。有趣的是，左顶叶α-tACS诱导的准确性调制与左运动前皮质中的电场大小直接相关。
总体而言，结果证实了α偏侧化在隐蔽视觉空间注意中起因果作用的观点，并表明左背侧注意网络的顶叶和运动前脑区对微妙的tACS神经调制的易感性增加。
