Longitudinal Investigation of Sleep, Memory, and Brain Development Across the Nap Transition

项目总结 睡眠稳定大脑皮层区域的记忆，优化突触组织，释放海马体 用于持续学习。在儿童早期，午睡起着至关重要的作用，通过睡眠来增强记忆力。 从属记忆巩固。有鉴于此，人们仍然不知道为什么孩子们在小睡后会过渡到 还处在一个充满学问的阶段。我们预测关键的大脑发育发生在这个时候，使得 中午“卸载”记忆不再是必要的。在这里，我们提出了第一个纵向研究 伴随午睡过渡而来的认知、生理和神经变化。中心假设是 儿童早期大脑(特别是海马体)的成熟会产生更多的信息 在不受干扰的情况下保留，减少了在午睡期间频繁合并的需要。我们假设 这些变化导致了双相睡眠(午睡和过夜睡眠)到单相睡眠(过夜睡眠) 过渡。为了检验这一点，我们将招募180名参与者(36-54个月)，并使用纵向设计 评估大脑发育与记忆、睡眠生理和午睡状态之间的关系。 NAP状态将通过活动记录仪进行实时监控，并通过家长报告的生态瞬间进行验证 评估。在午睡和夜间睡眠期间，将用多导睡眠图来评估睡眠。记忆将会 用一项旨在挖掘海马区依赖记忆的记忆相似性任务进行评估。评估 将在午睡之前和之后发生(与对照相同的清醒间隔)，并在之前和之后再次发生 随后的通宵睡眠。大脑的宏观/微观结构和解剖/功能连接将 用核磁共振测量。目标1是找出预测双相睡眠向单相睡眠转变的神经标记物。 目标2是研究睡眠转换过程中睡眠依赖记忆处理的变化。目标3是 检查睡眠过渡期间白天和夜间睡眠微结构和地形图的变化。目标 4是检查睡眠结构、记忆和大脑在睡眠过渡期间的相互关系 潜伏期变化得分模型。拟议工作的创新方面包括：实时跟踪国家行动方案 同一受试者的纵向转换；检查午睡和过夜睡眠的微观结构和 地形学.全面和有针对性的脑发育测量.由海马体调节的测量 记忆；以及潜在变化分数建模。这项工作还将产生一个新颖而丰富的数据集，用于其他 我们小组和其他人进行的分析，以测试替代结果，探索额外大脑的贡献 区域，并评估来自其他著名睡眠理论的其他假设。这项工作将具有重要的意义 通过加强对睡眠调节和睡眠的潜在机制的了解，对人类健康的影响 睡眠对认知健康和表现的影响以及睡眠中生物标志物的识别 可能有助于确定风险和健康结果。

PROJECT SUMMARY Sleep stabilizes memories in cortical regions and optimizes synaptic organization, freeing up the hippocampus for ongoing learning. In early childhood, naps serve a critical function, enhancing memory through sleep- dependent memory consolidation. Given this, it remains unknown why children transition out of naps when they are still in a stage rich with learning. We predict that critical brain development occurs at this time, making the mid-day “unloading” of memories no longer essential. Here we propose the first longitudinal study of the cognitive, physiological, and neural changes that accompany the nap transition. The central hypothesis is that maturation of the brain (in particular, the hippocampus) during early childhood results in more information being retained without interference, reducing the need for frequent consolidation that takes place during naps. We posit that these changes contribute to the biphasic (nap and overnight sleep) to monophasic (overnight sleep) sleep transition. To examine this, we will recruit 180 participants (36-54 months) and use a longitudinal design to assess brain development in relation to memory, sleep physiology, and nap status across the nap transition. Nap status will be monitored in real-time with actigraphy and verified via parent-reported ecological momentary assessments. Sleep will be assessed with polysomnography during the nap and overnight sleep. Memory will be assessed with a mnemonic similarity task, designed to tap hippocampal-dependent memory. Assessments will occur before and after a nap (with an equivalent interval awake as a control) and again before and after subsequent overnight sleep. Brain macro/micro structure and anatomical/functional connectivity will be measured with MRI. Aim 1 is to identify neural markers that predict the shift from biphasic to monophasic sleep. Aim 2 is to examine changes in sleep-dependent memory processing across the sleep transition. Aim 3 is to examine changes in diurnal and nocturnal sleep microstructure and topography across the sleep transition. Aim 4 is to examine interrelations among sleep architecture, memory, and the brain across the sleep transition using latent change score modeling. Innovative aspects of the proposed work include: real-time tracking of nap transitions longitudinally within the same subjects; examination of nap and overnight sleep microstructure and topography; comprehensive and targeted measures of brain development; measures of hippocampal-mediated memory; and latent change score modeling. This work will also result in a novel and rich dataset for additional analyses by our group and others to test alternative outcomes, explore the contribution of additional brain regions, and assess additional hypotheses from other prominent sleep theories. This work will have significant implications for human health by enhancing understanding of the mechanisms underlying sleep regulation and the consequences of sleep on cognitive health and performance and identification of biomarkers in sleep which may be useful in identifying risk and health outcomes.