Individual Differences in Habitual Sleep Quality and Episodic Memory Network Activity Across the Adult Lifespan

在正常衰老过程中，最常见和最令人痛苦的认知衰退之一是情景记忆。在日常生活中，这可能表现为忘记一个人的名字，但不是人。个体间存在显著差异，一些老年人表现出与年轻人相当的情景记忆表现和神经募集。现有的理论表明，可塑性的生活方式因素，如睡眠，有助于这种可变性，但尚未得到充分的证据。与年龄相关的习惯性睡眠质量下降，睡眠与支持记忆的大脑区域神经功能之间的关系，以及睡眠在情景记忆巩固中的作用，使睡眠成为一个重要的生活方式因素。这项研究的主要目标是阐明睡眠质量的个体差异在多大程度上影响了神经活动，而神经活动反过来又影响了正常成年人的情景记忆成功。从高中到研究生水平的学生接受实践培训，了解与人类记忆功能相关的认知神经科学研究的各个方面，以及影响其在不同成人寿命样本中的健康和生活方式因素。这项研究对于了解可塑性，个体差异因素如何影响衰老中的认知能力下降的潜在影响很大。这些来自大规模种族多样性样本的结果将通过提供近似年龄，特定大脑系统，以及睡眠质量最重要的记忆方面，以及睡眠干预在一般人群中可能最有效的记忆方面。它背后的活动是正常衰老中情景记忆衰退的主要原因。睡眠质量与PFC完整性及其相关的网络连接有关。正常的衰老已被证明会对这种活动、睡眠质量和情景记忆表现产生负面影响，但这些变量之间的关系尚不清楚。该项目的总体目标是确定与年龄相关的睡眠中断在多大程度上有助于学习过程中PFC网络活动，进而影响情景记忆表现。提出了一个中介模型，其中睡眠质量差部分介导的负面影响，健康老龄化的情景记忆通过减少分辨率的干扰在学习过程中，一个主要的年龄相关的认知控制缺陷。90名没有睡眠障碍的年轻人，中年人和老年人参与者的不同样本，执行多个情景记忆任务，这些任务对不同的干扰分辨率功能进行测量，以评估睡眠不良的负面影响的普遍性。情景记忆是通过行为评估的，并通过功能磁共振成像测量支持大脑活动。为了评估模型对情景记忆的特异性，测试了情景记忆和项目记忆。在学习后立即测试记忆力，并在24小时后延迟测试，以分别评估睡眠对巩固新学习的影响。通过筛选和统计分析控制了多种混淆因素的影响，包括药物、午睡、抑郁和运动。睡眠的客观测量是使用活动记录仪获得的，这是评估大量个人在家中自然地、以最小的干扰来评估多天习惯性睡眠模式的最佳方法。调解结果从平均睡眠估计，前一天晚上的记忆测试，和夜间到夜间的变化进行了比较，以分离的影响，习惯性睡眠不佳的变量或一个贫穷的夜晚的睡眠。单变量分析用于识别PFC区域，该PFC区域支持由活动定义的干扰分辨率，该活动在逐个试验的基础上与多变量模式分析（MVPA）衍生的干扰信号相关。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

One of the most common and distressing cognitive declines in normal aging is in episodic memory. In everyday life this might manifest as forgetting a person's name but not the person. Substantial inter-individual variability exists, with some older individuals showing episodic memory performance and neural recruitment equivalent to some young. Existing theories suggest that malleable lifestyle factors, like sleep, contribute to this variability but are not yet well-informed by such evidence. Established age-related declines in habitual sleep quality, the relationship between sleep and neural functioning in memory-supporting brain regions, and the role of sleep in episodic memory consolidation make sleep an essential lifestyle factor to examine. The primary goal of the proposed research is to elucidate the extent to which individual differences in sleep quality contribute to those in neural activity that, in turn, contribute to episodic memory success across the normal adult lifespan. Students from high school through graduate level receive hands on training in all aspects of conducting cognitive neuroscience research pertinent to human memory functioning and the health and lifestyle factors that influence it in diverse, adult lifespan samples. The potential impact of this research for understanding how malleable, individual difference factors affect cognitive decline in aging is high. These results from a large, racially diverse sample will inform existing theories of cognitive changes across the lifespan and future interventions by providing knowledge of the approximate age, specific brain systems, and aspects of memory for which sleep quality is most important and for which sleep interventions may be most effective in the general population.Difficulty utilizing cognitive control and the patterns of prefrontal cortical (PFC) activity underlying it is a major contributor to episodic memory decline in normal aging. Sleep quality is related to PFC integrity and its associated network connectivity. Normal aging has been shown to negatively affect this activity, sleep quality, and episodic memory performance but the relationship between these variables is unclear. The overarching goal of this project is to determine the extent to which age-related sleep disruptions contribute to those in PFC network activity during learning that, in turn, affect episodic memory performance. A mediation model is proposed in which poor sleep quality partially mediates the negative impact of healthy aging on episodic memory via reduced resolution of interference during learning, a major age-related cognitive control deficit. A diverse sample of 90 young, middle-aged, and older adult participants without sleep disorders, perform multiple episodic memory tasks that tax different interference resolution functions is measured to assess the generalizability of the negative impact of poor sleep. Episodic memory is assessed behaviorally and supporting brain activity measured with fMRI. In order to evaluate the specificity of the model to episodic memory, both episodic and item memory are tested. Memory is tested immediately following learning and after a 24-hour delay in order to separately assess the impact of sleep on new learning from consolidation. The influence of multiple confounds, including medication, naps, depression, and exercise is controlled through screening and statistical analyses. Objective measures of sleep are obtained using actigraphy, the best method for assessing habitual sleep patterns over multiple days for a large number of individuals naturally, in their homes, with minimal intrusion. Mediation results from average sleep estimates, the night immediately prior to memory testing, and night-to-night variability are compared in order to separate the impact of habitually poor sleep from variable or a poor night's sleep. Univariate analyses are used to identify PFC regions that support resolution of interference defined by activity that is correlated on a trial-by-trial basis with multivariate pattern analysis (MVPA)-derived interference signals. Functional connectivity analyses are additionally applied to identify the networks affected by sleep quality.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.