Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
Proc Natl Acad Sci U S A. 2013 Aug 27;110(35):14432-7. doi: 10.1073/pnas.1308285110. Epub 2013 Aug 12.
The brain is assumed to be hypoactive during cardiac arrest. However, the neurophysiological state of the brain immediately following cardiac arrest has not been systematically investigated. In this study, we performed continuous electroencephalography in rats undergoing experimental cardiac arrest and analyzed changes in power density, coherence, directed connectivity, and cross-frequency coupling. We identified a transient surge of synchronous gamma oscillations that occurred within the first 30 s after cardiac arrest and preceded isoelectric electroencephalogram. Gamma oscillations during cardiac arrest were global and highly coherent; moreover, this frequency band exhibited a striking increase in anterior-posterior-directed connectivity and tight phase-coupling to both theta and alpha waves. High-frequency neurophysiological activity in the near-death state exceeded levels found during the conscious waking state. These data demonstrate that the mammalian brain can, albeit paradoxically, generate neural correlates of heightened conscious processing at near-death.
大脑在心脏骤停期间被假定为低活跃状态。然而，心脏骤停后大脑的神经生理状态尚未被系统地研究过。在这项研究中，我们对经历实验性心脏骤停的大鼠进行了连续脑电图记录，并分析了功率密度、相干性、有向连通性和跨频耦合的变化。我们发现，心脏骤停后 30 秒内出现了短暂的同步伽马振荡激增，早于等电脑电图。心脏骤停期间的伽马振荡是全局的且高度相干的；此外，该频段表现出对前后向有向连通性的显著增加，以及与θ波和α波的紧密相位耦合。濒死状态下的高频神经生理活动超过了清醒状态下的活动水平。这些数据表明，哺乳动物大脑可以在濒死状态下产生增强意识处理的神经相关物，尽管这似乎有些矛盾。
