School of Psychiatry, University of New South Wales, Sydney, Australia.
Neurobiol Aging. 2012 May;33(5):899-913. doi: 10.1016/j.neurobiolaging.2010.06.022. Epub 2010 Aug 17.
We examine normal aging from the perspective of topological patterns of structural brain networks constructed from two healthy age cohorts 20 years apart. Based on graph theory, we constructed structural brain networks using 90 cortical and subcortical regions as a set of nodes and the interregional correlations of grey matter volumes across individual brains as edges between nodes, and further analyzed the topological properties of the age-specific networks. We found that the brain structural networks of both cohorts had small-world architecture, and the older cohort (N = 374; mean age = 66.6 years, range 64-68) had lower global efficiency but higher local clustering in the brain structural networks compared with the younger cohort (N = 428; mean age = 46.7, range 44-48). The older cohort had reduced hemispheric asymmetry and lower centrality of certain brain regions, such as the bilateral hippocampus, bilateral insula, left posterior cingulated, and right Heschl gyrus, but that of the prefrontal cortex (PFC) was not different. These structural network differences may provide the basis for changes in functional connectivity and indeed cognitive function as we grow older.
我们从相隔 20 年的两个健康年龄队列的结构脑网络拓扑模式的角度来研究正常衰老。基于图论，我们使用 90 个皮质和皮质下区域作为节点集，并使用个体大脑之间的灰质体积的区域间相关性作为节点之间的边缘，构建了结构脑网络，并进一步分析了年龄特定网络的拓扑特性。我们发现，两个队列的脑结构网络都具有小世界架构，与年轻队列（N = 428；平均年龄 = 46.7，范围 44-48）相比，老年队列（N = 374；平均年龄 = 66.6，范围 64-68）的脑结构网络全局效率较低，但局部聚类较高。老年队列的某些脑区的半球不对称性和中心性降低，如双侧海马体、双侧岛叶、左后扣带回和右颞上回，但前额叶皮层（PFC）的中心性没有差异。这些结构网络差异可能为我们随着年龄的增长功能连接甚至认知功能的变化提供基础。
