Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, China.
Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
Elife. 2021 Jul 27;10:e65099. doi: 10.7554/eLife.65099.
Sleep is essential in maintaining physiological homeostasis in the brain. While the underlying mechanism is not fully understood, a 'synaptic homeostasis' theory has been proposed that synapses continue to strengthen during awake and undergo downscaling during sleep. This theory predicts that brain excitability increases with sleepiness. Here, we collected transcranial magnetic stimulation measurements in 38 subjects in a 34 hr program and decoded the relationship between cortical excitability and self-report sleepiness using advanced statistical methods. By utilizing a combination of partial least squares regression and mixed-effect models, we identified a robust pattern of excitability changes, which can quantitatively predict the degree of sleepiness. Moreover, we found that synaptic strengthen occurred in both excitatory and inhibitory connections after sleep deprivation. In sum, our study provides supportive evidence for the synaptic homeostasis theory in human sleep and clarifies the process of synaptic strength modulation during sleepiness.
睡眠对于维持大脑的生理稳态至关重要。虽然其潜在机制尚未完全阐明,但已经提出了一种“突触稳态”理论,即突触在清醒时持续增强,而在睡眠时进行缩减。该理论预测,大脑兴奋性会随着困倦感的增加而增强。在这里,我们在 34 小时的方案中收集了 38 名受试者的经颅磁刺激测量值,并使用先进的统计方法解码了皮质兴奋性与自我报告困倦感之间的关系。通过使用偏最小二乘回归和混合效应模型的组合,我们确定了一种兴奋性变化的稳健模式,它可以定量预测困倦程度。此外,我们发现睡眠剥夺后兴奋性和抑制性连接都发生了突触增强。总之,我们的研究为人类睡眠中的突触稳态理论提供了支持性证据,并阐明了睡眠过程中突触强度调节的过程。