The link between NREM sleep oscillations and brain plasticity

睡眠在学习和记忆中起着至关重要的作用。越来越多的证据支持这样一种观点，即大脑中使用频率更高的区域需要更多的睡眠。在非快速眼动（NREM）睡眠期间，特定类型的脑电波（用脑电图测量），如慢波（0.3-4赫兹）和纺锤波（12-15赫兹），特别与大脑可塑性有关，即根据经验重组神经通路的能力。有趣的是，我们的研究表明，衰老强烈调节睡眠中的慢波和纺锤波。然而，慢波和纺锤波中与年龄相关的变化及其功能后果的机制仍然未知。我们的主要假设是，与年龄相关的慢波和纺锤波的变化与大脑重组神经通路的能力的变化有关。为了验证这一点，我们将评估睡眠如何影响大脑可塑性，以及大脑可塑性的变化如何改变年轻人和老年人的睡眠。具体而言，我们将评估12小时的睡眠间隔是否能更好地维持经颅磁刺激（一种操纵大脑活动的创新技术）引起的大脑可塑性，或通过脑成像测量记忆任务和随后的大脑激活的表现。我们还将评估在年轻和老年受试者中，经颅磁刺激或记忆任务引起的大脑活动变化如何影响随后睡眠中的慢波和纺锤波。我们希望为NREM睡眠振荡与大脑可塑性的年龄相关变化之间的相互关系提供重要线索。

Sleep plays a crucial role in learning and memory. Increasing evidence supports the idea that brain areas that have been used more than others need more sleep. Specific types of brain waves (measured with an electroencephalogram) during non-rapid-eye-movement (NREM) sleep, such as slow waves (0.3-4 Hz) and spindles (12-15 Hz), are particularly involved in brain plasticity, i.e. the ability to reorganize neural pathways based on experience. Interestingly, our research showed that aging strongly modulates slow waves and spindle during sleep. Yet the mechanisms underlying age-related changes in slow waves and spindles and their functional consequences are still unknown. Our main hypothesis is that age-related changes in slow waves and spindles are associated with changes in the brain's ability to reorganize neural pathways. To test this, we will evaluate how sleep impacts brain plasticity and how changes in brain plasticity modify sleep in young and older subjects. Specifically, we will assess whether a 12-hour interval with or without sleep better maintains cerebral plasticity induced by transcranial magnetic stimulation (an innovative technique to manipulate brain activity) or performance on a memory task and consequent cerebral activation, as measured with brain imaging. We will also evaluate in young and older subjects how a change in brain activity induced by transcranial magnetic stimulation or a memory task impacts slow waves and spindles during subsequent sleep. We hope to provide essential cues as to how age-related changes in NREM sleep oscillations and in brain plasticity are interrelated.