Gu Yue, Li Liangfang, Zhang Yining, Ma Junji, Yang Chenfan, Xiao Yu, Shu Ni, Can Cam, Lin Ying, Dai Zhengjia
Department of Psychology, Sun Yat-sen University, Guangzhou, China, 510006.
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China, 100875.
Neuroimage. 2022 Jun;253:119125. doi: 10.1016/j.neuroimage.2022.119125. Epub 2022 Mar 21.
Previous studies have demonstrated that the brain functional modular organization, which is a fundamental feature of the human brain, would change along the adult lifespan. However, these studies assumed that each brain region belonged to a single functional module, although there has been convergent evidence supporting the existence of overlap among functional modules in the human brain. To reveal how age affects the overlapping functional modular organization, this study applied an overlapping module detection algorithm that requires no prior knowledge to the resting-state fMRI data of a healthy cohort (N = 570) aged from 18 to 88 years old. A series of measures were derived to delineate the characteristics of the overlapping modular structure and the set of overlapping nodes (brain regions participating in two or more modules) identified from each participant. Age-related regression analyses on these measures found linearly decreasing trends in the overlapping modularity and the modular similarity. The number of overlapping nodes was found increasing with age, but the increment was not even over the brain. In addition, across the adult lifespan and within each age group, the nodal overlapping probability consistently had positive correlations with both functional gradient and flexibility. Further, by correlation and mediation analyses, we showed that the influence of age on memory-related cognitive performance might be explained by the change in the overlapping functional modular organization. Together, our results revealed age-related decreased segregation from the brain functional overlapping modular organization perspective, which could provide new insight into the adult lifespan changes in brain function and the influence of such changes on cognitive performance.
先前的研究表明，大脑功能模块化组织作为人类大脑的一个基本特征，会在成年期发生变化。然而，这些研究假设每个脑区都属于单一功能模块，尽管已有越来越多的证据支持人类大脑中功能模块之间存在重叠。为了揭示年龄如何影响重叠功能模块化组织，本研究将一种无需先验知识的重叠模块检测算法应用于一个年龄在18至88岁之间的健康队列（N = 570）的静息态功能磁共振成像数据。我们推导了一系列指标来描述重叠模块结构的特征以及从每个参与者中识别出的重叠节点（参与两个或更多模块的脑区）集合。对这些指标进行的年龄相关回归分析发现，重叠模块化和模块相似性呈线性下降趋势。重叠节点的数量随年龄增加，但在大脑中的增加并不均匀。此外，在整个成年期以及每个年龄组内，节点重叠概率始终与功能梯度和灵活性呈正相关。进一步通过相关性和中介分析，我们表明年龄对记忆相关认知表现的影响可能由重叠功能模块化组织的变化来解释。总之，我们的结果从大脑功能重叠模块化组织的角度揭示了与年龄相关的分离减少，这可为大脑功能在成年期的变化以及这些变化对认知表现的影响提供新的见解。
