The role of sleep in age-related decline in learning and memory

描述（由申请人提供）：衰老伴随着记忆和认知功能的逐渐下降。老年人的睡眠质量和效率也会下降。虽然人们普遍认为睡眠在学习和记忆中起着至关重要的作用，但与年龄有关的睡眠中断和记忆缺陷之间的联系尚不清楚。我们之前已经证明，学习诱导的皮层新突触连接的形成代表了与长期记忆存储相关的结构变化。我们的初步数据表明，睡眠促进了突触的形成和年轻成年动物学习后的表现改善。此外，在老年小鼠的运动皮层中，学习诱导的突触形成减少。基于这些发现，我们假设与年龄相关的睡眠障碍有助于减少学习依赖突触的形成和行为改善。在这个应用中，我们将通过结合突触结构和功能的体内成像，在同一动物中记录和行为测试来验证这一假设。这项提议有两个具体目的。在第一个目标中，我们将研究睡眠在年轻，中年和老年小鼠的学习依赖突触重塑和行为表现中的作用。这将验证睡眠在促进突触形成和记忆编码方面的益处在老年小鼠中减弱的假设。在第二个目标中，我们将使用体内钙成像来确定任务相关神经元的睡眠依赖性再激活是否在衰老过程中减少，以及这种睡眠再激活的缺乏是否介导了学习相关的突触缺陷。该项目首次在活体大脑中单个神经元和突触的水平上探索睡眠在与年龄相关的学习和记忆衰退中的作用。该项目的成功完成将为未来探索睡眠异常导致阿尔茨海默病等神经系统疾病认知功能障碍的机制奠定基础。

DESCRIPTION (provided by applicant): Aging is accompanied by a progressive decline in memory and cognitive function. Aging people also experience a deterioration of sleep quality and efficiency. Although it is widely acknowledged that sleep has a critical role in learning and memory, the link between age-related sleep disruption and memory deficits remains unclear. We have previously shown that learning-induced formation of new synaptic connections in the cortex represents structural changes correlated with long-term memory storage. Our preliminary data suggests that sleep promotes synapse formation and performance improvement after learning in young adult animals. Moreover, learning-induced synapse formation is reduced in the motor cortex of aged mice. Based on these findings, we hypothesize that age-related sleep impairment contributes to the reduction in learning-dependent synapse formation and behavioral improvement. In this application, we will test this hypothesis by combining in vivo imaging of synapse structure and function, recording and behavioral testing in the same animals. The proposal has two specific aims. In the first aim, we will examine the role of sleep in learning-dependent synapse remodeling and behavioral performance in young, middle-aged and old mice. This will test the hypothesis that the benefit of sleep in promoting synapse formation and memory encoding is diminished in older mice. In the second aim, we will use in vivo calcium imaging to determine whether sleep- dependent reactivation of task-related neurons is reduced in aging and whether such deficiency in sleep reactivation mediates learning-related synaptic deficits. The proposed project explores, for the first time, the role of sleep in age-related declie in learning and memory at the level of individual neurons and synapses in the living brain. Successful completion of the project will lay the foundation for future studies exploring the mechanisms by which sleep abnormalities contribute to cognitive dysfunction in neurological diseases such as Alzheimer's disease.