Center for BrainHealth®, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA.
Center for BrainHealth®, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA; Department of Psychology, University of California, Riverside, Riverside, CA, USA.
Brain Res. 2021 Jul 15;1763:147431. doi: 10.1016/j.brainres.2021.147431. Epub 2021 Mar 15.
Aging entails a multifaceted complex of changes in macro- and micro-structural properties of human brain gray matter (GM) and white matter (WM) tissues, as well as in intellectual abilities. To better capture tissue-specific brain aging, we combined volume and distribution properties of diffusivity indices to derive subject-specific age scores for each tissue. We compared age-related variance between younger and older adults for GM and WM age scores, and tested whether tissue-specific age scores could explain different effects of aging on fluid (Gf) and crystalized (Gc) intelligence in younger and older adults. Chronological age was strongly associated with GM (R = 0.73) and WM (R = 0.57) age scores. The GM age score accounted for significantly more variance in chronological age in younger relative to older adults (p < 0.001), whereas the WM age score accounted for significantly more variance in chronological age in older compared to younger adults (p < 0.025). Consistent with existing literature, younger adults outperformed older adults in Gf while older adults outperformed younger adults in Gc. The GM age score was negatively associated with Gf in younger adults (p < 0.02), whereas the WM age score was negatively associated with Gc in older adults (p < 0.02). Our results provide evidence for differences in the effects of age on GM and WM in younger versus older adults that may contribute to age-related differences in Gf and Gc.
衰老涉及到人类大脑灰质 (GM) 和白质 (WM) 组织的宏观和微观结构特性以及智力能力的多方面复杂变化。为了更好地捕捉组织特异性的大脑衰老，我们将扩散指数的体积和分布特性结合起来，为每个组织得出特定于个体的年龄分数。我们比较了 GM 和 WM 年龄分数在年轻和老年成年人之间的年龄相关方差，并测试了组织特异性年龄分数是否可以解释衰老对年轻和老年成年人液体智力 (Gf) 和晶体智力 (Gc) 的不同影响。实际年龄与 GM (R = 0.73) 和 WM (R = 0.57) 年龄分数呈强相关。GM 年龄分数在年轻成年人中与实际年龄的相关性明显高于老年成年人（p < 0.001），而 WM 年龄分数在老年成年人中与实际年龄的相关性明显高于年轻成年人（p < 0.025）。与现有文献一致，年轻成年人在 Gf 方面的表现优于老年成年人，而老年成年人在 Gc 方面的表现优于年轻成年人。GM 年龄分数与年轻成年人的 Gf 呈负相关（p < 0.02），而 WM 年龄分数与老年成年人的 Gc 呈负相关（p < 0.02）。我们的研究结果提供了证据，表明 GM 和 WM 在年轻成年人和老年成年人中的年龄影响存在差异，这可能导致 Gf 和 Gc 的年龄相关差异。
