Age and cortical structure are both associated with cognition, but characterizing this relationship remains a challenge. A popular approach is to use functional network organization of the cortex as an organizing principle for post-hoc interpretations of structural results. In the current study, we introduce two complimentary approaches to structural analyses that are guided by a-priori functional network maps. Specifically, we systematically investigated the relationship of cortical structure (thickness and surface area) of distinct functional networks to two cognitive domains sensitive to age-related decline thought to rely on both common and distinct processes (executive function and episodic memory) in older adults. We quantified the cortical structure of individual functional network’s predictive ability and spatial extent (i.e., number of significant regions) with cognition and its mediating role in the age-cognition relationship. We found that cortical thickness, rather than surface area, predicted cognition across the majority of functional networks. The default mode and somatomotor network emerged as particularly important as they appeared to be the only two networks to mediate the age-cognition relationship for both cognitive domains. In contrast, thickness of the salience network predicted executive function and mediated the age-cognition relationship for executive function. These relationships remained significant even after accounting for global cortical thickness. Quantifying the number of regions related to cognition and mediating the age-cognition relationship yielded similar patterns of results. This study provides a potential approach to organize and describe the apparent widespread regional cortical structural relationships with cognition and age in older adults.

年龄和皮质结构都与认知相关，但描述这种关系仍然是一个挑战。一种流行的方法是使用皮层的功能网络组织作为结构结果事后解释的组织原则。在当前的研究中，我们引入了两种由先验功能网络图指导的互补的结构分析方法。具体来说，我们系统地研究了不同功能网络的皮质结构（厚度和表面积）与对年龄相关衰退敏感的两个认知域的关系，这两个认知域被认为依赖于老年人的共同和独特过程（执行功能和情景记忆）。我们量化了个体功能网络的预测能力和空间范围（即重要区域的数量）与认知的皮质结构及其在年龄认知关系中的中介作用。我们发现，皮层厚度（而不是表面积）可以预测大多数功能网络的认知能力。默认模式和躯体运动网络显得尤为重要，因为它们似乎是调节两个认知领域的年龄认知关系的唯一两个网络。相反，显着网络的厚度预测执行功能并调节执行功能的年龄-认知关系。即使在考虑了整体皮质厚度之后，这些关系仍然很重要。量化与认知相关的区域数量并调节年龄-认知关系产生了类似的结果模式。这项研究提供了一种潜在的方法来组织和描述老年人中明显广泛的区域皮质结构与认知和年龄的关系。