Ma Yijia, Brown Joshua A, Chen Chaowen, Ding Mingzhou, Wu Wei, Li Wen
Louis A. Faillace, MD, Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, TX.
J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL.
eNeuro. 2025 Mar 11;12(3). doi: 10.1523/ENEURO.0449-24.2025.
Alpha (8-12 Hz) oscillations and default mode network (DMN) activity dominate the brain's intrinsic activity in the temporal and spatial domains, respectively. They are thought to play crucial roles in the spatiotemporal organization of the complex brain system. Relatedly, both have been implicated, often concurrently, in diverse neuropsychiatric disorders, with accruing electroencephalogram/magnetoencephalogram (EEG/MEG) and functional magnetic resonance imaging (fMRI) data linking these two neural activities both at rest and during key cognitive operations. Prominent theories and extant findings thus converge to suggest a mechanistic relationship between alpha oscillations and the DMN. Here, we leveraged simultaneous EEG-fMRI data acquired before and after alpha-frequency transcranial alternating current stimulation (-tACS) and observed that -tACS tightened the dynamic coupling between spontaneous fluctuations in alpha power and DMN connectivity (especially, in the posterior DMN, between the posterior cingulate cortex and the bilateral angular gyrus). In comparison, no significant changes were observed for temporal correlations between power in other oscillatory frequencies and connectivity in other major networks. These results thus suggest an inherent coupling between alpha and DMN activity in humans. Importantly, these findings highlight the efficacy of -tACS in regulating the DMN, a clinically significant network that is challenging to target directly with non-invasive methods. Alpha (8-12 Hz) oscillations and the default mode network (DMN) represent two major intrinsic activities of the brain. Prominent theories and extant findings converge to suggest a mechanistic relationship between alpha oscillations and the DMN. Combining simultaneous electroencephalogram-functional-magnetic-resonance imaging (EEG-fMRI) with alpha-frequency transcranial alternating current stimulation (α-tACS), we demonstrated tightened coupling between alpha oscillations and DMN connectivity. These results lend credence to an inherent alpha-DMN link. Given DMN dysfunctions in multiple major neuropsychiatric conditions, the findings also highlight potential utility of α-tACS in clinical interventions by regulating the DMN.
阿尔法（8 - 12赫兹）振荡和默认模式网络（DMN）活动分别在时间和空间领域主导着大脑的固有活动。它们被认为在复杂大脑系统的时空组织中发挥着关键作用。相关地，两者常常同时涉及多种神经精神疾病，越来越多的脑电图/脑磁图（EEG/MEG）和功能磁共振成像（fMRI）数据将这两种神经活动在静息状态和关键认知操作过程中联系起来。因此，突出的理论和现有发现都表明阿尔法振荡与默认模式网络之间存在一种机制关系。在此，我们利用在阿尔法频率经颅交流电刺激（α-tACS）前后采集的同步EEG-fMRI数据，观察到α-tACS加强了阿尔法功率的自发波动与默认模式网络连通性之间的动态耦合（特别是在后扣带回皮质和双侧角回之间的后默认模式网络中）。相比之下，其他振荡频率的功率与其他主要网络连通性之间的时间相关性未观察到显著变化。这些结果表明人类的阿尔法和默认模式网络活动之间存在内在耦合。重要的是，这些发现突出了α-tACS在调节默认模式网络方面的功效，默认模式网络是一个临床上重要的网络，用非侵入性方法直接靶向具有挑战性。阿尔法（8 - 12赫兹）振荡和默认模式网络（DMN）代表大脑的两种主要固有活动。突出的理论和现有发现都表明阿尔法振荡与默认模式网络之间存在一种机制关系。通过将同步脑电图-功能磁共振成像（EEG-fMRI）与阿尔法频率经颅交流电刺激（α-tACS）相结合，我们证明了阿尔法振荡与默认模式网络连通性之间的耦合加强。这些结果证实了阿尔法-默认模式网络之间存在内在联系。鉴于默认模式网络在多种主要神经精神疾病中功能失调，这些发现还突出了α-tACS通过调节默认模式网络在临床干预中的潜在效用。
