睡眠稳态的电生理机制

大脑需要稳态系统来维持神经元的正常活动。睡眠不足会影响到有机体的生理功能，因此清醒时不断累积的睡眠压力会迫使哺乳动物进入睡眠状态，长时间清醒（睡眠剥夺）则会延长或加深随后的睡眠，这一现象被称为睡眠稳态（sleep homeostasis）。探明睡眠稳态的电生理机制有利于改善睡眠，治疗相关疾病，但目前仍存在许多问题。鉴于此，本文围绕睡眠稳态的电生理机制，首先关注睡眠稳态公认的电生理标志物——慢波活动，接下来介绍神经元放电率的相关研究，最后从脑区差异、睡眠阶段、学习记忆和物种差异几个方面进行展望。

Electrophysiological Mechanisms of Sleep Homeostasis

The brain’s neural circuits consist of a large number of highly unstable networks. Despite the existence of many internal and external factors that continuously disturb 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, whereby a force must be generated to move neuronal activity back toward this target. Sleep is one of the well-known physiological states in the regulation of homeostasis. Sleep pressure increases during wakefulness and decreases during sleep. When sleep is lost (e.g., sleep deprivation), this loss is compensated by extending or strengthening subsequent sleep. These phenomena are known as sleep homeostasis. The dysregulation of sleep homeostasis accompanies brain-related diseases such as schizophrenia, bipolar disorder, major depressive disorder, and autism spectrum disorder. More importantly, it can significantly undermine the basis of traditional sleep hygiene practices for these diseases. Therefore, clarifying the mechanisms of sleep homeostasis is important for therapy, but it remains an unsolved mystery. In addition to pharmacological treatment, non-invasive brain stimulation has become one of the most promising tools for clinical treatment in recent years due to its low cost, portability and low incidence of side effects. In order to promote relevant technologies, this review will focus on the electrophysiological mechanisms of sleep homeostasis. We first discuss the electrophysiological marker of sleep homeostasis, slow-wave activity, then move to the neuronal firing rates, finally discuss more aspects of sleep homeostasis, including differences in brain area, sleep stages, learning and individual differences.