Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, TX 75080, USA.
Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, TX 75080, USA.
Neuropsychologia. 2018 Jun;114:50-64. doi: 10.1016/j.neuropsychologia.2018.04.013. Epub 2018 Apr 12.
Studies investigating the strength and membership of regions within multiple functional networks primarily focus on either resting state or single cognitive tasks. The goals of the current study were to investigate whether task-related functional connectivity changes with task complexity, and whether this connectivity-complexity relationship is age-sensitive. We assessed seed-to-voxel functional connectivity for the default mode network (DMN) and two attentional networks [cingulo-opercular (CO), fronto-parietal (FP)] in three cognitive control tasks of increasing complexity (Single task, Dual task, and Memory Updating), across younger and older adults (N = 52; N = 23; N = 29). The three tasks systematically varied in cognitive control demands due to differing maintenance, switching, and updating requirements. Functional connectivity for all networks, resulting from task > rest contrasts, increased with greater task complexity, irrespective of age and gray matter volume. Moreover, between-network connectivity for DMN, CO, and FP regions was greatest for working memory updating, the most complex task. Regarding age-related differences in accuracy, none were observed for Single or Dual tasks, but older adults had poorer accuracy in Memory Updating. More anterior frontal clusters of functional connectivity were observed for older, compared to younger, adults; these were limited to seeds of the two attentional networks. Importantly, increased connectivity in these additional frontal regions in older adults were non-compensatory, because they were associated with detrimental task performance, especially Memory Updating. For the Memory Updating > Rest, the younger > older contrast resulted in greater DMN seed connectivity to regions in the other two attentional networks, implicating increased reliance on between-network connectivity for the DMN seeds during complex cognitive tasks. Our results also implicate functional connectivity between attentional networks and the cerebellum during cognitive control. Reliability of multiple seeds in the seed-to-voxel connectivity is also discussed.
研究主要集中在静息状态或单一认知任务上，以探索多个功能网络中区域的强度和成员关系。本研究的目的是调查任务相关的功能连接是否随任务复杂性而变化，以及这种连接-复杂性关系是否对年龄敏感。我们评估了默认模式网络（DMN）和两个注意力网络[扣带回-顶叶（CO）、额顶叶（FP）]的种子到体素功能连接，这些网络在三个认知控制任务中具有不同的复杂性（单一任务、双重任务和记忆更新），包括年轻和老年参与者（N=52；N=23；N=29）。由于不同的维持、转换和更新要求，三个任务在认知控制需求上系统地变化。来自任务>休息对比的所有网络的功能连接都随着任务复杂性的增加而增加，与年龄和灰质体积无关。此外，DMN、CO 和 FP 区域之间的网络间连接在工作记忆更新中最大，这是最复杂的任务。关于准确性的年龄相关差异，在单一任务或双重任务中均未观察到，但老年人在记忆更新方面的准确性较差。与年轻人相比，老年人的功能连接更靠前的额叶簇；这些仅限于两个注意力网络的种子。重要的是，老年人这些额外额叶区域的连接增加是非补偿性的，因为它们与任务表现的损害有关，尤其是记忆更新。对于记忆更新>休息，年轻>老年的对比导致 DMN 种子与其他两个注意力网络中的区域的连接性更大，这意味着在复杂认知任务中，DMN 种子对网络间连接的依赖性增加。我们的结果还表明，在认知控制期间，注意力网络与小脑之间存在功能连接。还讨论了种子到体素连接中多个种子的可靠性。
