Thalamo-cortical mechanisms underlying changes in amplitude and frequency of human alpha oscillations
Thalamo-cortical mechanisms underlying changes in amplitude and frequency of human alpha oscillations
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DOI：
10.1016/j.neuroimage.2012.12.018
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发表时间：
2013-04-15
期刊：
影响因子：
5.7
通讯作者：
van Putten, Michel J. A. M.
中科院分区：
文献类型：
--
作者：
Hindriks, Rikkert;van Putten, Michel J. A. M.
虽然已有大量研究致力于建立脑电α振荡的幅度和频率的变化与认知过程之间的相关性，但目前尚不清楚这种变化是通过哪些生理机制带来的。在这项研究中，我们使用脑电产生的生物物理模型，以获得对丘脑-皮质系统内可能低于这种阿尔法反应的功能变化的基本了解。这项研究的主要结果是，尽管丘脑-皮质系统的生理学特征是大量的参数，但阿尔法反应实际上只依赖于三个变量。生理上，这些变量决定了前馈、皮质-丘脑-皮质和皮质内回路的共振特性。通过研究这些共振的调制对脑电阿尔法振荡的幅度和频率的影响，建立了该模型可以再现实验观察到的阿尔法反应的多样性，以及实验发现阿尔法幅度的变化通常比阿尔法频率的变化大一个数量级。建模结果也符合这样一个事实，即阿尔法反应通常与表征认知过程的指数线性相关。通过研究突触和固有神经元参数的影响，我们发现阿尔法反应反映了皮质激活的变化，这与阿尔法活动在认知加工需求中选择性地抑制皮质区域的假设是一致的。作为这些分析如何应用于特定实验方案的一个例子，我们复制了苯二氮类药物诱导的阿尔法反应，并阐明了推测的丘脑-皮质机制。这项研究报告的发现提供了一个基本的生理学框架，在这个框架内可以理解在特定实验方案中观察到的阿尔法反应。(C)2013 Elsevier Inc.保留所有权利。
Although a large number of studies have been devoted to establishing correlations between changes in amplitude and frequency of EEG alpha oscillations and cognitive processes, it is currently unclear through which physiological mechanisms such changes are brought about. In this study we use a biophysical model of EEG generation to gain a fundamental understanding of the functional changes within the thalamo-cortical system that might underly such alpha responses. The main result of this study is that, although the physiology of the thalamo-cortical system is characterized by a large number of parameters, alpha responses effectively depend on only three variables. Physiologically, these variables determine the resonance properties of feedforward, cortico-thalamo-cortical, and intra-cortical circuits. By examining the effect of modulations of these resonances on the amplitude and frequency of EEG alpha oscillations, it is established that the model can reproduce the variety of experimentally observed alpha responses, as well as the experimental finding that changes in alpha amplitude are typically an order of magnitude larger than changes in alpha frequency. The modeling results are also in line with the fact that alpha responses often correlate linearly with indices characterizing cognitive processes. By investigating the effect of synaptic and intrinsic neuronal parameters, we find that alpha responses reflect changes in cortical activation, which is consistent with the hypothesis that alpha activity serves to selectively inhibit cortical regions during cognitive processing demands. As an example of how these analyses can be applied to specific experimental protocols, we reproduce benzodiazepine-induced alpha responses and clarify the putative underlying thalamo-cortical mechanisms. The findings reported in this study provide a fundamental physiological framework within which alpha responses observed in specific experimental protocols can be understood. (C) 2013 Elsevier Inc. All rights reserved.