The Fate of Incoming Stimuli during NREM Sleep is Determined by Spindles and the Phase of the Slow Oscillation.
The Fate of Incoming Stimuli during NREM Sleep is Determined by Spindles and the Phase of the Slow Oscillation.
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DOI：
10.3389/fneur.2012.00040
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发表时间：
2012
影响因子：
3.4
通讯作者：
Maquet P
中科院分区：
文献类型：
--
作者：
Schabus M;Dang-Vu TT;Heib DP;Boly M;Desseilles M;Vandewalle G;Schmidt C;Albouy G;Darsaud A;Gais S;Degueldre C;Balteau E;Phillips C;Luxen A;Maquet P
本研究旨在利用同步脑电(EEG)/功能磁共振成像(FMRI)记录来确定非快速眼动(NREM)睡眠中与听觉刺激相关的神经生理反应。早些时候有报道称，听觉刺激在觉醒和NREM睡眠中都会在听觉皮质、丘脑和尾状核产生双侧激活。然而，由于自发的膜电位波动，在NREM过程中，皮质反应可能是高度可变的。在这里，我们现在研究大脑对音调反应的调制，这取决于睡眠纺锤波的存在或不存在以及缓慢振荡的相位。13名健康青年受试者在3 T扫描仪上成功地进行了前半夜2-4NREM睡眠时的扫描。受试者没有睡眠不足，并根据(I)睡眠纺锤体的存在或(Ii)在(±300 ms)音调传递期间的慢振荡阶段对声音进行事后分类。然后将这些检测到的声音作为fMRI分析中感兴趣的回归变量输入。有趣的是，觉醒样反应--尽管在大小和位置上有所改变--在NREM睡眠中持续存在，但在目前的纺锤波(如之前发表在Dang-Vu等人上的)和慢振荡的负向进行阶段除外，在此期间，反应变得不太一致，甚至不存在。虽然缓慢振荡的阶段没有改变初级感觉皮层的大脑反应，但它确实调节了较高皮质水平的反应。此外，脑电分析显示，在轻度睡眠纺锤波存在时，大脑对音调有明显的N550反应，并表明在深度NREM睡眠中，大脑在缓慢振荡的正向斜率期间反应更快。大脑对外界刺激开放的短暂时间窗口的存在与这样一个事实一致，即即使在深度睡眠期间，也可以检测到有意义的事件。总之，我们的结果强调了这样一个概念，即大脑活动的自发波动深刻地改变了大脑在所有行为状态下对外部信息的反应，包括深度NREM睡眠。
The present study aimed at identifying the neurophysiological responses associated with auditory stimulation during non-rapid eye movement (NREM) sleep using simultaneous electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) recordings. It was reported earlier that auditory stimuli produce bilateral activation in auditory cortex, thalamus, and caudate during both wakefulness and NREM sleep. However, due to the spontaneous membrane potential fluctuations cortical responses may be highly variable during NREM. Here we now examine the modulation of cerebral responses to tones depending on the presence or absence of sleep spindles and the phase of the slow oscillation. Thirteen healthy young subjects were scanned successfully during stage 2–4 NREM sleep in the first half of the night in a 3 T scanner. Subjects were not sleep-deprived and sounds were post hoc classified according to (i) the presence of sleep spindles or (ii) the phase of the slow oscillation during (±300 ms) tone delivery. These detected sounds were then entered as regressors of interest in fMRI analyses. Interestingly wake-like responses – although somewhat altered in size and location – persisted during NREM sleep, except during present spindles (as previously published in Dang-Vu et al.,) and the negative going phase of the slow oscillation during which responses became less consistent or even absent. While the phase of the slow oscillation did not alter brain responses in primary sensory cortex, it did modulate responses at higher cortical levels. In addition EEG analyses show a distinct N550 response to tones during the presence of light sleep spindles and suggest that in deep NREM sleep the brain is more responsive during the positive going slope of the slow oscillation. The presence of short temporal windows during which the brain is open to external stimuli is consistent with the fact that even during deep sleep meaningful events can be detected. Altogether, our results emphasize the notion that spontaneous fluctuations of brain activity profoundly modify brain responses to external information across all behavioral states, including deep NREM sleep.