We used graph theoretical measures to investigate the hypothesis that structural brain connectivity constrains the influence of functional connectivity on the relation between age and fluid cognition. Across 143 healthy, community-dwelling adults 19-79 years of age, we estimated structural network properties from diffusion-weighted imaging and functional network properties from resting-state functional magnetic resonance imaging. We confirmed previous reports of age-related decline in the strength and efficiency of structural networks, as well as in the connectivity strength within and between structural network modules. Functional networks, in contrast, exhibited age-related decline only in system segregation, a measure of the distinctiveness among network modules. Aging was associated with decline in a composite measure of fluid cognition, particularly tests of executive function. Functional system segregation was a significant mediator of age-related decline in executive function. Structural network properties did not directly influence the age-related decline in functional system segregation. The raw correlational data underlying the graph theoretical measures indicated that structural connectivity exerts a limited constraint on age-related decline in functional connectivity.

中文翻译：

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大脑结构和功能连接对流体认知年龄相关差异的影响


我们使用图论方法来研究这样的假设：结构性大脑连接限制了功能连接对年龄和流体认知之间关系的影响。在 143 名 19-79 岁的健康社区成年人中，我们通过扩散加权成像估计了结构网络特性，并通过静息态功能磁共振成像估计了功能网络特性。我们证实了之前的报告，即结构网络的强度和效率以及结构网络模块内部和之间的连接强度与年龄相关的下降。相比之下，功能网络仅在系统隔离方面表现出与年龄相关的衰退，系统隔离是网络模块之间独特性的衡量标准。衰老与流体认知综合测量的下降有关，尤其是执行功能测试的下降。功能系统分离是与年龄相关的执行功能下降的重要中介因素。结构网络特性并不直接影响功能系统隔离与年龄相关的下降。图论测量背后的原始相关数据表明，结构连接对与年龄相关的功能连接下降施加有限的限制。