人类睡眠稳态的神经电生理特征:基于SEEG的证据
文献类型：学位论文
| 作者 | 肖雪 |
| 答辩日期 | 2023-06 |
| 文献子类 | 硕士 |
| 授予单位 | 中国科学院大学 |
| 授予地点 | 中国科学院心理研究所 |
| 其他责任者 | 王亮 |
| 关键词 | 睡眠稳态 慢波活动 功率谱截距 颅内脑电 |
| 学位名称 | 理学硕士 |
| 学位专业 | 认知神经科学 |
| 其他题名 | Neuronhvsiological Features of Human Sleep Homeostasis: Evidence from Stereoelectroencephalography |
| 中文摘要 | The brain's neural circuits consist of a large number of highly unstable networks. Yet despite the existence of mangy internal and external factors that continuously perturb the balance, our brains employ an array of homeostatic mechanisms that allow neurons or neural circuits to sense how active they are, and when they deviate from a target value, a force must be generated to move neuronal activity back toward this target. This mechanism that maintains phyiological variables within a dynamic range around a `set point' is called homeostasis. Homeostasis is what allows the organism to maintain its relative stability in the face of changing external stimuli, and sleep and neural activity are both important physiological variables in the regulation of homeostasis. Sleep is essential for the energy recovery of the organism, and to ensure proper functioning, the organism has evolved a mechanism of sleep homeostasis, in which sleep pressure increases during wakefulness and decreases during sleep, maintaining sleep pressure near a set point. Similarly, neural activity increases during wakefulness and decreases during sleep, and it appears that a stable neural activity is associated with sleep homeostasis. Previous studies have confirmed that decreased cortical neural activity in rodents do correlate with slow-wave activity, an electrophysiological marker of sleep homeostasis. However, the decrease in neural activity in the hippocampal region was also found to be modulated by REM sleep, with a sharp decrease in neural activity during REM sleep, pulling down overall activity and thus showing lower neural activity during late sleep. The mechanism for the decrease in neural activity during sleep remains debated. It is worth noting that much of the current evidence comes from rodent studies, and it is not known whether differences in sleep architecture between humans and rodents affect the decrease in neural activity during sleep. It is difficult to record neuronal activity directly in humans, but epileptic patients have intracranially implanted electrodes to record local field potential signals due to therapeutic needs, and its power spectral density (PSD) offset of local field potentials has been shown to be a robust estimate of neural activity, which provides an excellent tool and chance for this study. In order to investigate whether and by what mechanism human neural activity decrease during sleep, this study performed a series of analyses using intracranial electrodes to record local field potentials during sleep in epileptic patients. We used the offset of the local field potential power spectrum as an indirect measure of neural activity. Study 1 focused on the deep brain region, the hippocampus, which has been found to reduce neural activity during sleep in rodents, and the results of this study further confirm this finding. The results of Study 1 showed that: 1) offset was significantly lower in late sleep (last N2) than in early sleep (first N2), suggesting that neural activity decreases during sleep; 2) offset decreased significantly after REM sleep, and the decrease correlated positively with changes in offset across the night, confirming that human REM sleep is related with the decrease in neural activity during sleep; 3) hippocampal slow wave activity decreased continuously during sleep, and the decrease significantly predicted the change in offset, suggesting that hippocampal slow wave activity is also related with the decrease in neural activity; 4) there was no interaction between REM sleep and slow wave activity on the downregulation of neural activity. Study 2 further explored why there are two independent mechanisms for the decrease in neural activity during sleep, and we hypothesis that this may be due to the fact that the two mechanisms prefer different brain regions. We explored other brain regions excluding the hippocampus and found that: 1) not all brain regions exhibited a decrease in offset during sleep, suggesting that the decrease in neural activity during sleep is local; 2) the decrease in slow-wave activity in prefrontal cortex and entorhinal cortex, which are involved in learning and memory, were most pronounced, whereas the decrease in offset after REM sleep was mainly in the temporal cortex, supporting the hypothesis of the present study. Thus, the results of the present study suggest that human brain neural activity decreases during sleep and that both slow-wave activity and REM sleep are associated with this process. However, the two are not directly related and do not overlap exactly in brain regions. |
| 英文摘要 | 大脑神经环路由大量高度不稳定的网络组成，尽管存在许多扰乱平衡的内部和外部因素，但大脑采用了一系列稳态机制，允许神经元或神经环路感知活动水平，当大脑活动水平偏离基线值后，便会产生特定的力量来使神经元活动回到基线水平，这种将生理变量维持在一个“设定点”附近的动态机制便是稳态C homeostasis。正是由于稳态机制，有机体才能在不断变化的外界刺激中维持自身的相对稳定，睡眠和神经活动都是稳态调节的重要生理变量。 睡眠对有机体的能量恢复至关重要，为了保证有机体机能的正常运行，有机体进化出了一套睡眠稳态(sleep homeostasis)机制，睡眠压力在清醒时增加，睡眠时减少，将睡眠压力维持在设定点附近。类似的，神经元活动也会在清醒时增加，在睡眠过程中减少，似乎神经活动稳定与睡眠稳态相关。前人研究证实，啮齿动物皮层的神经元活动下降与睡眠稳态的电生理标志物一一慢波活动确实相关，但同时研究发现海马脑区神经元活动的下降则会受到REM睡眠的调制，在REM睡眠期间神经元活动急剧下降，拉低了整体活动水平，从而在睡眠晚期表现出更低的神经活动。可以看出，睡眠期间神经活动下降的机制仍然存在争论。值得注意的是，目前相关证据大多来自啮齿动物研究，而人类与啮齿动物的睡眠结构存在差异，这种差异是否会影响到睡眠期间神经活动的下降尚不得而知。在人类上直接记录单个神经元的放电活动较为困难，但癫痈病人由于治疗需求会在颅内植入电极，这些颅内电极能够记录到局部场电位信号，而该信号的功率谱(power spectral density, PSD)截距值(C offset)已被证实是单细胞神经活动水平的强有力估计指标，这为本研究提供了绝佳的工具和条件。 为了探明人类神经活动是否会在睡眠期间下降以及下降的机制，本研究通过颅内电极记录了癫痈病人睡眠时的局部场电位信号，将局部场电位功率谱的截距值作为神经元活动水平的间接测量指标进行了一系列分析。研究一聚焦深部脑区海马，该脑区在啮齿动物上已被发现会在睡眠过程中减少神经活动，而本研究结果则进一步证实了该发现。研究一结果显示:1)睡眠晚期(最后一个N2期)的截距值显著低于睡眠早期(第一个N2期)，表明神经活动在睡眠期间减少;2)REM睡眠前后截距值显著下降，下降程度与整晚截距值的变化正相关，证实了人类REM睡眠与睡眠期间神经活动的下降相关;3)海马慢波活动在睡眠期间不断减少，减少程度能够显著预测截距值的变化，说明海马慢波活动与神经活动的下降相关;4 ) REM睡眠和慢波活动对神经活动的下调作用并没有交互作用。研究二进一步探讨了为何睡眠期间神经活动下降存在两个独立的作用机制，本研究假设这可能是由于这两个机制偏好的脑区不同，因此分析了除海马外的其他脑区，结果发现:1)睡眠期间并不是所有的脑区都表现出截距值的下降，说明神经活动在睡眠期间的下降是局部的;2)慢波活动的减少在涉及学习记忆的前额叶皮层和内嗅皮层最为明显，而REM睡眠后截距值的下降则主要在颗叶皮层，证明了本研究的假设。因此，本研究的结果说明了，人类大脑在睡眠期间神经活动下降，慢波活动和REM睡眠都与此过程相关，但二者并无直接关联，并且作用脑区不完全重合。 |
| 语种 | 中文 |
| 源URL | [http://ir.psych.ac.cn/handle/311026/46098]  |
| 专题 | 心理研究所_健康与遗传心理学研究室 |
| 推荐引用方式 GB/T 7714 | 肖雪. 人类睡眠稳态的神经电生理特征:基于SEEG的证据[D]. 中国科学院心理研究所. 中国科学院大学. 2023. |
入库方式： OAI收割
来源：心理研究所
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