Steriade M
Laboratory of Neurophysiology, Laval University, Faculty of Medicine, Quebec, Canada G1K 7P4.
Neuroscience. 2006;137(4):1087-106. doi: 10.1016/j.neuroscience.2005.10.029. Epub 2005 Dec 15.
Different brain rhythms, with both low-frequency and fast-frequency, are grouped within complex wave-sequences. Instead of dissecting various frequency bands of the major oscillations that characterize the brain electrical activity during states of vigilance, it is conceptually more rewarding to analyze their coalescence, which is due to neuronal interactions in corticothalamic systems. This concept of unified brain rhythms does not only include low-frequency sleep oscillations but also fast (beta and gamma) activities that are not exclusively confined to brain-activated states, since they also occur during slow-wave sleep. The major factor behind this coalescence is the cortically generated slow oscillation that, through corticocortical and corticothalamic drives, is effective in grouping other brain rhythms. The experimental evidence for unified oscillations derived from simultaneous intracellular recordings of cortical and thalamic neurons in vivo, while recent studies in humans using global methods provided congruent results of grouping different types of slow and fast oscillatory activities. Far from being epiphenomena, spontaneous brain rhythms have an important role in synaptic plasticity. The role of slow-wave sleep oscillation in consolidating memory traces acquired during wakefulness is being explored in both experimental animals and human subjects. Highly synchronized sleep oscillations may develop into seizures that are generated intracortically and lead to inhibition of thalamocortical neurons, via activation of thalamic reticular neurons, which may explain the obliteration of signals from the external world and unconsciousness during some paroxysmal states.
不同频率的脑节律，包括低频和高频，都被归为复杂的波序列。与其剖析在警觉状态下表征脑电活动的主要振荡的各个频段，从概念上来说，分析它们的合并更有意义，这种合并是由于皮质丘脑系统中的神经元相互作用所致。这种统一脑节律的概念不仅包括低频睡眠振荡，还包括快速（β和γ）活动，这些活动并非仅局限于脑激活状态，因为它们也会在慢波睡眠期间出现。这种合并背后的主要因素是皮质产生的慢振荡，它通过皮质皮质和皮质丘脑驱动，有效地将其他脑节律聚集在一起。统一振荡的实验证据来自于体内对皮质和丘脑神经元的同步细胞内记录，而最近在人类中使用整体方法的研究也得出了不同类型的慢振荡和快振荡活动聚集的一致结果。自发脑节律绝非附带现象，它们在突触可塑性中起着重要作用。慢波睡眠振荡在巩固清醒期间获得的记忆痕迹方面的作用，正在实验动物和人类受试者中进行探索。高度同步的睡眠振荡可能发展为皮质内产生的癫痫发作，并通过丘脑网状神经元的激活导致丘脑皮质神经元的抑制，这可能解释了在某些发作状态下来自外部世界的信号消失和意识丧失的原因。
