Functional connectivity - the co-activation of brain regions - forms the basis of the brain's functional architecture. Often measured during resting-state (i.e., in a task-free setting), patterns of functional connectivity within and between brain networks change with age. These patterns are of interest to aging researchers because age differences in resting-state connectivity relate to older adults' relative cognitive declines. Less is known about age differences in large-scale brain networks during directed tasks. Recent work in younger adults has shown that patterns of functional connectivity are highly correlated between rest and task states. Whether this finding extends to older adults remains largely unexplored. To this end, we assessed younger and older adults' functional connectivity across the whole brain using fMRI while participants underwent resting-state or completed directed tasks (e.g., a reasoning judgement task). Resting-state and task functional connectivity were less strongly correlated in older as compared to younger adults. This age-dependent difference could be attributed to significantly lower consistency in network organization between rest and task states among older adults. Older adults had less distinct or segregated networks during resting-state. This more diffuse pattern of organization was exacerbated during directed tasks. Finally, the default mode network, often implicated in neurocognitive aging, contributed strongly to this pattern. These findings establish that age differences in functional connectivity are state-dependent, providing greater insight into the mechanisms by which aging may lead to cognitive declines.

中文翻译：

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衰老与休息和任务状态下大脑网络的功能结构不成比例地减弱有关

功能连接——大脑区域的共同激活——构成了大脑功能结构的基础。通常在静息状态（即在无任务环境中）测量，大脑网络内部和之间的功能连接模式随着年龄的增长而变化。这些模式对老年研究人员很感兴趣，因为静息状态连接的年龄差异与老年人的相对认知能力下降有关。关于定向任务期间大规模大脑网络的年龄差异知之甚少。最近对年轻人的研究表明，功能连接模式在休息和任务状态之间高度相关。这一发现是否适用于老年人在很大程度上仍未得到探索。为此，我们评估了年轻人和老年人的 当参与者经历静息状态或完成定向任务（例如，推理判断任务）时，使用 fMRI 跨越整个大脑的功能连接。与年轻人相比，老年人的静息状态和任务功能连接性的相关性较低。这种与年龄相关的差异可归因于老年人休息和任务状态之间网络组织的一致性显着降低。老年人在静息状态下的网络不太明显或隔离。这种更分散的组织模式在有针对性的任务中会加剧。最后，通常与神经认知老化有关的默认模式网络对这种模式有很大贡献。这些发现证实了功能连接的年龄差异是依赖于状态的，