Liu Jianxi, Huang Mingcong, Hu Kang, Xia Nannan, Linli Zeqiang
School of Mathematics and Statistics, Guangdong University of Foreign Studies, Guangzhou, China.
School of Information Engineering, Wuhan Business University, Wuhan, China.
J Neuroimaging. 2025 Mar-Apr;35(2):e70036. doi: 10.1111/jon.70036.
Extensive research has been carried out to investigate changes in various gray matter (GM) regions during the aging process using resting-state functional MRI. However, the impact of aging on the functional connectivity (FC) between white matter (WM) and GM, particularly white matter-gray matter functional connectivity (WM-GM FC), remains largely unknown. This study proposes a novel method for constructing functional networks that integrate both WM and GM.
By utilizing data from a lifespan cohort of 439 healthy adults, we devised a covariance-based approach to establish a gray matter-white matter-gray matter (GM-WM-GM) mediated network. The FC between GM and WM was quantified using the Johns Hopkins University International Consortium of Brain Mapping-Diffusion Tensor Imaging-81 WM atlas in combination with the Automated Anatomical Labeling atlas. First, the WM-GM FC was calculated via Pearson correlation coefficients between WM and GM regions, followed by the standardization of the resulting matrix. The GM-WM-GM FC was then constructed using the covariance matrix. Furthermore, topological properties were calculated for GM-WM-GM networks. Finally, the age effect of GM-WM-GM and its topology were explored.
Our findings reveal a significant age-related decline in intranetwork connectivity and global network efficiency, while internetwork connectivity followed an inverted U-shaped pattern, suggesting functional dedifferentiation in the aging brain. Despite relatively stable local efficiency, the observed reduction in global efficiency indicates a weakening of long-range neural connections. Additionally, a decrease in network modularity further supports this trend.
These results offer novel insights into the age-associated reorganization of brain networks, enhancing our understanding of the neural mechanisms underlying normal aging.
利用静息态功能磁共振成像，已经开展了大量研究来探究衰老过程中各个灰质（GM）区域的变化。然而，衰老对白质（WM）与GM之间的功能连接（FC），尤其是白质-灰质功能连接（WM-GM FC）的影响，在很大程度上仍不清楚。本研究提出了一种构建整合WM和GM的功能网络的新方法。
通过利用来自439名健康成年人的全生命周期队列的数据，我们设计了一种基于协方差的方法来建立一个灰质-白质-灰质（GM-WM-GM）介导网络。GM与WM之间的FC使用约翰霍普金斯大学国际脑图谱联盟-扩散张量成像-81白质图谱结合自动解剖标记图谱进行量化。首先，通过WM和GM区域之间的皮尔逊相关系数计算WM-GM FC，然后对所得矩阵进行标准化。接着使用协方差矩阵构建GM-WM-GM FC。此外，还计算了GM-WM-GM网络的拓扑特性。最后，探讨了GM-WM-GM及其拓扑结构的年龄效应。
我们的研究结果显示，网络内连接性和全局网络效率随年龄显著下降，而网络间连接性呈倒U形模式，这表明衰老大脑中存在功能去分化。尽管局部效率相对稳定，但观察到的全局效率降低表明远程神经连接减弱。此外，网络模块化的降低进一步支持了这一趋势。
这些结果为大脑网络与年龄相关的重组提供了新的见解，增进了我们对正常衰老背后神经机制的理解。
