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

在正常衰老中，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，这可能会表现为忘记一个人的名字，但不会忘记这个人。个体间存在很大的差异性，一些年长的个体表现出与年轻人相同的情景记忆表现和神经招募。现有的理论表明，可延展的生活方式因素，如睡眠，导致了这种差异，但这些证据还没有充分说明这一点。与年龄相关的习惯性睡眠质量下降，睡眠和支持记忆的大脑区域的神经功能之间的关系，以及睡眠在间歇性记忆巩固中的作用，使睡眠成为需要研究的基本生活方式因素。这项拟议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有助于神经活动的差异，而神经活动反过来又有助于在正常成年人的一生中成功地进行情景记忆。从高中到研究生阶段的学生在进行与人类记忆功能相关的认知神经科学研究的方方面面，以及在不同的成年人寿命样本中影响人类记忆的健康和生活方式因素方面，都接受了动手培训。这项研究对于了解延展性、个体差异因素如何影响衰老中的认知衰退具有很高的潜在影响。这些来自不同种族的大样本的结果将通过提供关于大致年龄、特定大脑系统和记忆方面的知识，为现有的认知变化理论提供信息，这些方面对睡眠质量最重要，对一般人群来说，睡眠干预可能是最有效的。认知控制的困难以及其背后的前额叶皮质(PFC)活动模式是正常衰老中情景记忆下降的主要原因。睡眠质量与PFC的完整性及其相关的网络连接有关。正常衰老已被证明对这种活动、睡眠质量和情景记忆表现有负面影响，但这些变量之间的关系尚不清楚。这个项目的首要目标是确定与年龄相关的睡眠中断在多大程度上影响学习过程中PFC网络活动，进而影响情景记忆表现。提出了一个中介模型，在该模型中，睡眠质量差通过降低学习期间干扰的分辨率来部分地调节健康老龄化对情景记忆的负面影响，学习干扰是与年龄相关的主要认知控制缺陷。对90名没有睡眠障碍的年轻人、中年人和老年人的不同样本进行了测量，以评估睡眠不良的负面影响的概括性。情节记忆是通过行为和支持大脑活动的功能磁共振成像进行评估的。为了评价该模型对情景记忆的特异性，我们对情景记忆和项目记忆进行了测试。记忆测试是在学习后立即进行的，并在24小时的延迟之后进行，以便分别评估睡眠对巩固新学习的影响。包括药物、午睡、抑郁和锻炼在内的多种混杂因素的影响通过筛查和统计分析得到控制。客观的睡眠测量是使用活动记录法获得的，这是评估大量个人在家中自然地、在最小程度上干扰的多天习惯性睡眠模式的最佳方法。通过比较平均睡眠估计值、记忆力测试前一晚和夜间变异性得出的中介结果，以区分习惯性睡眠不良的影响与可变或夜间睡眠不良的影响。单变量分析用于识别PFC区域，该区域支持由逐个试验与多变量模式分析(MVPA)导出的干扰信号相关的活动定义的干扰的解决。此外，还应用了功能连通性分析来确定受睡眠质量影响的网络。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.