Cytoarchitectural brain changes during normal aging remain poorly characterized, and it is unclear whether patterns of brain aging differ by sex. This study used restriction spectrum imaging to examine associations between age and brain microstructure in 147 community-dwelling participants (aged 56-99 years). Widespread associations with age in multiple diffusion compartments, including increased free water, decreased restricted and hindered diffusion, and reduced neurite complexity, were observed in the cortical gray matter, the white matter tracts, and the hippocampus. Age differences in cortical microstructure were largely independent of atrophy. Associations were mostly global, although foci of stronger effects emerged in the fornix, anterior thalamic radiation and commissural fibers, and the medial temporal, orbitofrontal, and occipital cortices. Age differences were stronger and more widespread for women than men, even after adjustment for education, hypertension, and body mass index. Restriction spectrum imaging may be a convenient, noninvasive tool for monitoring changes in diffusion properties that are thought to reflect reduced cellular fractions and neurite density or complexity, which occur with typical aging, and for detecting sex differences in patterns of brain aging.

中文翻译：

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年龄与居住在社区的老年男性和女性的大脑微观结构之间的关联：Rancho Bernardo 研究

正常衰老过程中大脑细胞结构的变化仍然很差，目前还不清楚大脑衰老的模式是否因性别而异。本研究使用限制谱成像来检查 147 名社区参与者（56-99 岁）的年龄与大脑微观结构之间的关联。在皮质灰质、白质束和海马体中观察到多个扩散区室中与年龄的广泛关联，包括增加的游离水、减少的受限和受阻扩散以及降低的神经突复杂性。皮质微结构的年龄差异在很大程度上与萎缩无关。尽管在穹窿、前丘脑放射和连合纤维以及内侧颞、眶额、和枕叶皮质。即使在对教育、高血压和体重指数进行调整后，女性的年龄差异也比男性更大、更普遍。限制谱成像可能是一种方便的非侵入性工具，用于监测扩散特性的变化，这些变化被认为反映了典型衰老过程中发生的细胞分数和神经突密度或复杂性的减少，并用于检测大脑衰老模式中的性别差异。