Mazaheri Ali, Jensen Ole
Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Nijmegen, Netherlands.
Front Hum Neurosci. 2010 Oct 14;4:177. doi: 10.3389/fnhum.2010.00177. eCollection 2010.
The conventional assumption in human cognitive electrophysiology using EEG and MEG is that the presentation of a particular event such as visual or auditory stimuli evokes a "turning on" of additional brain activity that adds to the ongoing background activity. Averaging multiple event-locked trials is thought to result in the cancellation of the seemingly random phased ongoing activity while leaving the evoked response. However, recent work strongly challenges this conventional view and demonstrates that the ongoing activity is not averaged out due to specific non-sinusoidal properties. As a consquence, systematic modulations in ongoing activity can produce slow cortical evoked responses reflecting cognitive processing. In this review we introduce the concept of "rhythmic pulsing" to account for this specific non-sinusoidal property. We will explain how rhythmic pulsing can create slow evoked responses from a physiological perspective. We will also discuss how the notion of rhythmic pulsing provides a unifying framework linking ongoing oscillations, evoked responses and the brain's capacity to process incoming information.
在使用脑电图（EEG）和脑磁图（MEG）的人类认知电生理学中，传统的假设是，诸如视觉或听觉刺激等特定事件的呈现会引发额外的大脑活动“开启”，这种活动会叠加在持续的背景活动之上。人们认为，对多个事件锁定试验进行平均会导致看似随机的阶段性持续活动被抵消，而留下诱发反应。然而，最近的研究强烈挑战了这一传统观点，并表明由于特定的非正弦特性，持续活动不会被平均掉。因此，持续活动中的系统性调制可以产生反映认知处理的缓慢皮层诱发反应。在这篇综述中，我们引入“节律性脉冲”的概念来解释这种特定的非正弦特性。我们将从生理学角度解释节律性脉冲如何产生缓慢的诱发反应。我们还将讨论节律性脉冲的概念如何提供一个统一的框架，将持续振荡、诱发反应和大脑处理传入信息的能力联系起来。
