Language Section, Voice, Speech, and Language Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 2013 Jun 18;110(25):10300-5. doi: 10.1073/pnas.1217691110. Epub 2013 Jun 3.
Rapid eye movement (REM) sleep constitutes a distinct "third state" of consciousness, during which levels of brain activity are commensurate with wakefulness, but conscious awareness is radically transformed. To characterize the temporal and spatial features of this paradoxical state, we examined functional interactions between brain regions using fMRI resting-state connectivity methods. Supporting the view that the functional integrity of the default mode network (DMN) reflects "level of consciousness," we observed functional uncoupling of the DMN during deep sleep and recoupling during REM sleep (similar to wakefulness). However, unlike either deep sleep or wakefulness, REM was characterized by a more widespread, temporally dynamic interaction between two major brain systems: unimodal sensorimotor areas and the higher-order association cortices (including the DMN), which normally regulate their activity. During REM, these two systems become anticorrelated and fluctuate rhythmically, in reciprocally alternating multisecond epochs with a frequency ranging from 0.1 to 0.01 Hz. This unique spatiotemporal pattern suggests a model for REM sleep that may be consistent with its role in dream formation and memory consolidation.
快速眼动（REM）睡眠构成了一种独特的“第三状态”的意识，在此期间大脑活动水平与清醒时相当，但意识感知却发生了根本性的变化。为了描述这种矛盾状态的时间和空间特征，我们使用 fMRI 静息态连接方法研究了大脑区域之间的功能相互作用。支持默认模式网络（DMN）的功能完整性反映“意识水平”的观点，我们观察到在深度睡眠期间 DMN 功能解耦，在 REM 睡眠期间重新耦合（类似于清醒状态）。然而，与深度睡眠或清醒状态不同，REM 表现出两个主要大脑系统之间更广泛、更具时间动态性的相互作用：单一感觉运动区域和高级联合皮质（包括 DMN），它们通常调节其活动。在 REM 期间，这两个系统变得负相关，并以相互交替的多毫秒时相周期性波动，频率范围为 0.1 至 0.01 Hz。这种独特的时空模式为 REM 睡眠提供了一个模型，该模型可能与其在梦境形成和记忆巩固中的作用一致。
