Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, United States.
Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, United States.
Cereb Cortex. 2024 Mar 1;34(3). doi: 10.1093/cercor/bhae114.
Cognitive decline with aging involves multifactorial processes, including changes in brain structure and function. This study focuses on the role of white matter functional characteristics, as reflected in blood oxygenation level-dependent signals, in age-related cognitive deterioration. Building on previous research confirming the reproducibility and age-dependence of blood oxygenation level-dependent signals acquired via functional magnetic resonance imaging, we here employ mediation analysis to test if aging affects cognition through white matter blood oxygenation level-dependent signal changes, impacting various cognitive domains and specific white matter regions. We used independent component analysis of resting-state blood oxygenation level-dependent signals to segment white matter into coherent hubs, offering a data-driven view of white matter's functional architecture. Through correlation analysis, we constructed a graph network and derived metrics to quantitatively assess regional functional properties based on resting-state blood oxygenation level-dependent fluctuations. Our analysis identified significant mediators in the age-cognition relationship, indicating that aging differentially influences cognitive functions by altering the functional characteristics of distinct white matter regions. These findings enhance our understanding of the neurobiological basis of cognitive aging, highlighting the critical role of white matter in maintaining cognitive integrity and proposing new approaches to assess interventions targeting cognitive decline in older populations.
随着年龄的增长，认知能力下降涉及多种因素过程，包括大脑结构和功能的变化。本研究专注于白质功能特征的作用，这些特征反映在血氧水平依赖信号中，与年龄相关的认知恶化有关。在先前的研究证实通过功能磁共振成像获得的血氧水平依赖信号的可重复性和年龄依赖性的基础上，我们在这里采用中介分析来测试衰老是否通过白质血氧水平依赖信号的变化影响认知，从而影响各种认知领域和特定的白质区域。我们使用静息状态血氧水平依赖信号的独立成分分析将白质分割成相干的中枢，为白质的功能结构提供了数据驱动的视角。通过相关分析，我们构建了一个图网络，并得出了基于静息状态血氧水平依赖波动的定量评估区域功能特性的指标。我们的分析确定了年龄与认知关系中的显著中介因素，表明衰老通过改变不同白质区域的功能特征，对认知功能产生不同的影响。这些发现增强了我们对认知老化神经生物学基础的理解，突出了白质在维持认知完整性中的关键作用，并提出了评估针对老年人群认知能力下降的干预措施的新方法。
