Functional Role of NREM sleep oscillations in aging

衰老与睡眠的重要改变有关，包括睡眠持续时间缩短、睡眠变浅以及特定脑波(或大脑活动的振荡)减少，如慢波和纺锤波。陈述性记忆巩固的特定成分(即清晰回忆事实和事件的能力)也随着正常年龄的增长而显著下降。重要的是，慢波和纺锤波在加强睡眠期间大脑记忆痕迹方面发挥着重要作用。这项研究计划的长期目标是了解睡眠振荡在衰老中的功能作用。具体地说，我们将使用多模式方法来测试这一假设，即与年龄相关的睡眠振荡变化与大脑加强陈述性记忆的能力变化有关。我们的第一个具体目标是在学习了年轻和老年参与者的陈述性记忆任务后，定位于大脑皮层同步活动，并评估这些大脑皮层区域在睡眠振荡期间如何相互通信。我们预测，与控制任务相比，在学习之后，睡眠振荡期间的同步性将出现在更广泛、更相连的皮质区域集合中。我们还预计，这些影响在年龄较大的参与者中不会那么明显，在早上保持陈述性记忆任务的表现将与睡眠振荡期间增强的大脑皮层交流有关。我们的第二个具体目标是评估在年轻和年长参与者的头皮特定区域诱导弱电流以诱导睡眠振荡和增强对陈述性记忆任务的保持的效果。我们预测，与控制条件相比，年轻参与者，尤其是年长参与者的睡眠振荡将会增强，这将改善对陈述性记忆任务的保持。该研究计划将提供与年龄相关的睡眠振荡变化如何与大脑可塑性变化相关的关键知识。诱发睡眠振荡的方法学的发展为评估睡眠振荡的作用提供了一种创新的因果方法。本着NSERC授权的精神，这项研究计划还将促进新方法(电磁神经成像)和先进技术设备(基于波的神经刺激)的发展。总体目标是增强特定人群在睡眠期间的大脑可塑性，这些人群表现出睡眠振荡异常(例如，轻度认知障碍和帕金森病)。

Aging is associated with important modifications in sleep including shorter sleep duration, shallower sleep and reductions in specific brain waves (or oscillations of the brain activity) such as slow-waves and spindles. Specific components of declarative memory consolidation (i.e. ability to recall explicitly facts and events) also decline significantly with normal aging. Importantly, slow-waves and spindles play an important role in reinforcing cerebral memory traces during sleep. The long-term objective of this research program is to understand the functional role of sleep oscillations in aging. Specifically, we will use a multi-modal approach to test the hypothesis that age-related changes in sleep oscillations are associated with changes in the ability of the brain to strengthen declarative memory. Our first specific objective is to localize on the cortex synchronous activity and evaluate how these cortical areas communicate together during sleep oscillations after learning a declarative memory task in young and older participants. We predict that synchrony during sleep oscillations will emerge from a broader and more connected set of cortical regions after learning, as compared to the control task. We also expect that these effects will be less pronounced in older participants and that performance on the retention of a declarative memory task in the morning will be associated to enhanced cortical communication during sleep oscillations. Our second specific objective is to evaluate the effects of inducing weak electric currents on specific areas on the scalp to induce sleep oscillations and enhance retention on a declarative memory task in young and older participants. We predict that compared to a control condition, sleep oscillations will be enhanced in the young and, in particular, in the older participants, which will improve the retention on a declarative memory task. The research program will provide crucial knowledge as to how age-related changes in sleep oscillations are associated with changes in brain plasticity. The development of a methodology to induce sleep oscillations provides an innovative causal approach to assess the role of sleep oscillations. In the spirit of the NSERC mandate, this research program will also stimulate the development of new methodology (electromagnetic neuroimaging) and advanced technological devices (wave-based neurostimulation). The overall objective is the enhancement of brain plasticity during sleep in specific populations which show sleep oscillations abnormalities (e.g. mild cognitive impairment and Parkinson disease).