Posterior α activity is not phase-reset by visual stimuli
Posterior α activity is not phase-reset by visual stimuli
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DOI：
10.1073/pnas.0505785103
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发表时间：
2006-02-21
影响因子：
11.1
通讯作者：
Jensen, O
中科院分区：
文献类型：
--
作者：
Mazaheri, A;Jensen, O
目前存在着一种争论，即使用脑电图术或脑磁图术测量的事件相关电位和场是否是由于正在进行的振荡活动对给定刺激的响应而变得相位重置而产生的。我们进行了一项脑磁图研究，测量大脑活动对视觉刺激的反应。使用一种被称为相位保持指数的测量方法，我们研究了刺激前后α振荡活动(8-13赫兹)的相位。我们发现，在单次试验中，视觉刺激后的阿尔法振荡相对于刺激前的相位保持了它们的相位关系。这一发现反对正在进行的振荡的相位重置，认为它是视觉诱发反应的责任。与事件相关的领域主要可以通过刺激之前不存在的theta频段中的刺激锁定活动来解释。这些发现表明，不同的神经元事件负责产生持续的振荡和视觉诱发的反应。
There is currently a debate as to whether event-related potentials and fields measured by using electroencephalography or magnetoencephalography are generated by ongoing oscillatory activity becoming phase-reset in response to a given stimulus. We performed a magnetoencephalography study measuring brain activity in response to visual stimuli. Using a measure termed the phase-preservation index we investigated the phase of oscillatory alpha activity (8-13 Hz) before and after the stimulus. We found that in single trials the alpha oscillations after visual stimuli preserve their phase relationship with respect to the phase before the stimuli. This finding argues against phase-resetting of ongoing oscillations as being responsible for visually evoked responses. The event-related field can be explained primarily by stimulus-locked activity in the theta band that is absent before the stimulus. These findings suggest that different neuronal events are responsible for generating the ongoing oscillations and the visually evoked responses.