Viscoelastic and volumetric contributions to age-related cognitive decline

项目摘要/摘要 众所周知，典型的衰老伴随着流体认知能力的特征性下降，如 以及大脑结构完整性的下降。结构的完整性通常是从 测量大脑体积。然而，数量是一个粗略的衡量标准，不能考虑较小的规模。 可能导致认知结果减弱的变化。磁共振弹性成像(MRE) 是一种用于获得生物组织机械特性的非侵入性测量的新兴工具。AS 这样，MRE提供了对组织微结构健康状况的衡量。拟议的工作寻求(1) 评估MRE作为容量分析的补充工具在人类学习和研究中的效用 以及(2)建立MRE作为一种非常敏感的方法来描绘衰老中的退行性病变 大脑，特别是当体积结果不明确的时候。体积、MRE和认知数据将 收集自80名年龄在45岁到85岁之间的参与者。认知评估将衡量这两项指标 关系记忆能力(取决于海马体功能)和内隐序列学习能力 (取决于纹状体功能)。体积分析和MRE分析将集中在海马体和纹状体 具体地说。这些数据将被用来检查关系内存性能和 海马体体积和MRE衍生的海马体粘弹性，以及隐含序列学习 以及纹状体体积和粘弹性，以探索每一个对行为的独特贡献。它是 预计，与单纯的体积测量相比，粘弹性测量将提供额外的 在研究组织完整性对认知结果的影响时的解释能力。这项工作将 建立MRE作为研究衰老认知神经科学的有用工具，并强调 在评估结构完整性时选择适当的神经成像工具。生成的数据将具有 跟踪典型衰老中影响认知能力的结构变化的重要意义 海马区(如阿尔茨海默病)患者的诊断和治疗结果的跟踪 纹状体(如帕金森氏病)损害。

PROJECT SUMMARY/ABSTRACT It is well understood that typical aging is accompanied by characteristic declines in fluid cognitive abilities as well as declines in the structural integrity of the brain. Structural integrity has typically been inferred from measures of brain volume. Volume, however, is a gross measure that cannot account for smaller-scale changes that may be contributing to diminished cognitive outcomes. Magnetic resonance elastography (MRE) is an emerging tool for acquiring noninvasive measures of the mechanical properties of biological tissue. As such, MRE provides a measure of the microstructural health of the tissue. The proposed work seeks (1) to assess the utility of MRE as a complementary tool to volumetric analysis in the study of human learning and memory and also (2) to establish MRE as a critically sensitive method for mapping degeneration in the aging brain, particularly when volumetric outcomes are equivocal. Volumetric, MRE, and cognitive data will be collected from 80 participants between the ages of 45 and 85. The cognitive assessment will measure both relational memory abilities (dependent on hippocampal function) and implicit sequence learning abilities (dependent on striatal function). Volumetric and MRE analyses will focus on the hippocampus and striatum specifically. These data will be used to examine the relationship between relational memory performance and both hippocampal volume and MRE-derived hippocampal viscoelasticity, as well as implicit sequence learning and both striatal volume and viscoelasticity, to explore the unique contribution of each to behavior. It is expected that, compared to volumetric measures alone, viscoelasticity measures will provide additional explanatory power when investigating the impact of tissue integrity on cognitive outcomes. This work will establish MRE as a useful tool for the study of cognitive neuroscience of aging and highlight the importance of choosing appropriate neuroimaging tools when assessing structural integrity. The resulting data will have important implications for tracking structural changes that impact cognitive abilities in typical aging as well as the diagnosis and tracking of treatment outcomes for patients with hippocampal (e.g., Alzheimer’s disease) and striatal (e.g., Parkinson’s disease) impairments.