BOLD correlates of EEG alpha phase-locking and the fMRI default mode network
BOLD correlates of EEG alpha phase-locking and the fMRI default mode network
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DOI：
10.1016/j.neuroimage.2009.01.001
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发表时间：
2009-04-15
期刊：
影响因子：
5.7
通讯作者：
Koenig, T.
中科院分区：
文献类型：
--
作者：
Jann, K.;Dierks, T.;Koenig, T.
大脑区域的相位锁定或同步是大脑中信息处理的一个关键概念。在过去的几十年里，同步振荡在脑电中得到了广泛的观察和研究。脑电振荡发生在一个很宽的频率范围内。在脑电中，一种突出的振荡类型是阿尔法波段活动，通常出现在受试者醒着但闭着眼睛休息的时候。最近在同步的EEG/fMRI记录中研究了阿尔法节律的频谱功率，建立了一个广泛的皮质-丘脑网络。然而，频谱功率和同步性是不同的衡量标准，对BOLD效应和EEG同步性之间的相关性知之甚少。有趣的是，fMRI BOLD信号还显示出不同大脑区域的同步振荡。这些振荡描绘了所谓的静息状态网络(RSN)，它类似于同时进行的EEG/fMRI记录的相关模式。然而，这些大胆振荡的本质及其与脑电活动的关系仍然知之甚少。一种假设是，构成特定RSN的亚单位可能由不同的脑电节律协调。在这项研究中，我们报告了支持这一假设的证据。在阿尔法频段中，全球脑电同步(GF)的大胆关联位于特定RSN所涉及的大脑区域，例如“默认模式网络”。此外，我们的结果证实了这样的假设，即特定的RSN至少在阿尔法频段内是通过远程同步来组织的。最后，我们可以定位GFS粗体关联和相关RSN重叠的特定区域。因此，我们认为不仅脑电的频谱动力学很重要，而且它们的时空组织也很重要。(C)2009 Elsevier Inc.保留所有权利。
Phase locking or synchronization of brain areas is a key concept of information processing in the brain. Synchronous oscillations have been observed and investigated extensively in EEG during the past decades. EEG oscillations occur over a wide frequency range. In EEG, a prominent type of oscillations is alpha-band activity, present typically when a subject is awake, but at rest with closed eyes. The spectral power of alpha rhythms has recently been investigated in simultaneous EEG/fMRI recordings, establishing a wide-range cortico-thalamic network. However, spectral power and synchronization are different measures and little is known about the correlations between BOLD effects and EEG synchronization. Interestingly, the fMRI BOLD signal also displays synchronous oscillations across different brain regions. These oscillations delineate so-called resting state networks (RSNs) that resemble the correlation patterns of simultaneous EEG/fMRI recordings. However, the nature of these BOLD oscillations and their relations to EEG activity is still poorly understood. One hypothesis is that the subunits constituting a specific RSN may be coordinated by different EEG rhythms. In this study we report on evidence for this hypothesis. The BOLD correlates of global EEG synchronization (GFS) in the alpha frequency band are located in brain areas involved in specific RSNs, e. g. the 'default mode network'. Furthermore, our results confirm the hypothesis that specific RSNs are organized by long-range synchronization at least in the alpha frequency band. Finally, we could localize specific areas where the GFS BOLD correlates and the associated RSN overlap. Thus, we claim that not only the spectral dynamics of EEG are important, but also their spatio-temporal organization. (c) 2009 Elsevier Inc. All rights reserved.