Department of Medicine, The University of Melbourne, Parkville, VIC, 3010, Australia; Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, VIC, 3122, Australia.
School of Pharmacy, The University of Auckland, Auckland, New Zealand.
Neuroimage. 2020 Mar;208:116408. doi: 10.1016/j.neuroimage.2019.116408. Epub 2019 Nov 30.
The attenuation of the alpha rhythm following eyes-opening (alpha blocking) is among the most robust features of the human electroencephalogram with the prevailing view being that it is caused by changes in neuronal population synchrony. To further study the basis for this phenomenon we use theoretically motivated fixed-order Auto-Regressive Moving-Average (ARMA) time series modelling to study the oscillatory dynamics of spontaneous alpha-band electroencephalographic activity in eyes-open and eyes-closed conditions and its modulation by the NMDA antagonist ketamine. We find that the reduction in alpha-band power between eyes-closed and eyes-open states is explicable in terms of an increase in the damping of stochastically perturbed alpha-band relaxation oscillatory activity. These changes in damping are putatively modified by the antagonism of NMDA-mediated glutamatergic neurotransmission but are not directly driven by changes in input to cortex nor by reductions in the phase synchronisation of populations of near identical oscillators. These results not only provide a direct challenge to the dominant view of the role that thalamus and neuronal population de-/synchronisation have in the genesis and modulation of alpha electro-/magnetoencephalographic activity but also suggest potentially important physiological determinants underlying its dynamical control and regulation.
睁眼后 alpha 节律的衰减（alpha 阻断）是人类脑电图中最具特征性的现象之一，目前的观点认为，它是由神经元群体同步性的变化引起的。为了进一步研究这种现象的基础，我们使用理论驱动的固定阶数自回归移动平均（ARMA）时间序列模型来研究自发 alpha 波段脑电图活动的振荡动力学，以及 NMDA 拮抗剂氯胺酮对其的调制。我们发现，闭眼和睁眼状态之间 alpha 波段功率的降低可以用随机扰动 alpha 波段弛豫振荡活动阻尼的增加来解释。这种阻尼的变化被 NMDA 介导的谷氨酸能神经传递的拮抗作用所改变，但不是由皮质输入的变化或近相同振荡器群体的相位同步性的降低直接驱动的。这些结果不仅直接挑战了丘脑和神经元群体去同步化在 alpha 脑电/脑磁图活动的产生和调制中的作用的主导观点，而且还表明了其动力学控制和调节的潜在重要生理决定因素。
