Neuroscience Center, University of Helsinki Helsinki, Finland.
Front Psychol. 2011 Sep 5;2:204. doi: 10.3389/fpsyg.2011.00204. eCollection 2011.
Alpha-frequency band (8-14 Hz) oscillations are among the most salient phenomena in human electroencephalography (EEG) recordings and yet their functional roles have remained unclear. Much of research on alpha oscillations in human EEG has focused on peri-stimulus amplitude dynamics, which phenomenologically support an idea of alpha oscillations being negatively correlated with local cortical excitability and having a role in the suppression of task-irrelevant neuronal processing. This kind of an inhibitory role for alpha oscillations is also supported by several functional magnetic resonance imaging and trans-cranial magnetic stimulation studies. Nevertheless, investigations of local and inter-areal alpha phase dynamics suggest that the alpha-frequency band rhythmicity may play a role also in active task-relevant neuronal processing. These data imply that inter-areal alpha phase synchronization could support attentional, executive, and contextual functions. In this review, we outline evidence supporting different views on the roles of alpha oscillations in cortical networks and unresolved issues that should be addressed to resolve or reconcile these apparently contrasting hypotheses.
阿尔法频段（8-14 赫兹）的脑电波活动是人类脑电图（EEG）记录中最显著的现象之一，但它们的功能作用仍不清楚。人类 EEG 中阿尔法脑电波活动的大部分研究都集中在刺激前的振幅动态上，这些现象支持了这样一种观点，即阿尔法脑电波活动与局部皮质兴奋性呈负相关，并在抑制与任务无关的神经元处理方面发挥作用。这种阿尔法脑电波活动的抑制作用也得到了几项功能磁共振成像和经颅磁刺激研究的支持。然而，对局部和区域间阿尔法相位动态的研究表明，阿尔法频段的节律性可能也在活跃的与任务相关的神经元处理中发挥作用。这些数据表明，区域间的阿尔法相位同步可以支持注意力、执行和上下文功能。在这篇综述中，我们概述了支持不同观点的证据，这些观点涉及到阿尔法脑电波活动在皮质网络中的作用，以及为了解决或调和这些明显矛盾的假说而需要解决的未决问题。
