Recent neuroimaging studies have reported an age-related reduction in brain activations in response to working memory load in task-sensitive brain regions. The current fMRI study investigated the age-related differences in brain activations of the updating mechanism in working memory, which was not investigated in previous studies. With a hybrid block/event-related design, this study was able to examine changes in BOLD signals (i.e., neuromodulation) to increase in updating, a type of cognitive control that is understudied. Older adults were separated into young-old and old-old cohorts to examine whether, within healthy aging, the neuromodulation to cognitive control decreases with age. Our results show that younger adults activate left precentral gyrus and right cerebellum more during trials that require updating than trials that do not require updating. Although older adults showed reduced neuromodulation in these two regions, the old-old cohort failed to show any significant neuromodulation in response to updating. Moreover, older adults not only showed reduced suppressions of the default mode network (DMN) regions during the task, they also overactivated some of the DMN regions, esp. the old-old, when compared to the younger adults. Older adults also showed overactivations in a region (right precentral gyrus) that is contralateral to a task-sensitive region that was activated in the younger adults during updating. Brain-behavior correlations suggest that age-related overactivations of these DMN regions and the right precentral gyrus are maladaptive to their performance. Our results suggest that not only the neuromodulation in response to updating demands is diminished in healthy aging, older adults also show maladaptive increases in activations of task-irrelevant regions and reduced hemispheric specificity during updating. These effects are most pronounced in old-old cohort, compared to young-old, suggesting that age-related declines in neuromodulation during cognitive control is more pronounced in older cohorts within healthy aging.

中文翻译：

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工作记忆更新期间大脑激活的年龄相关差异：一项功能磁共振成像研究。

最近的神经影像学研究已报道，与任务敏感的大脑区域中的工作记忆负荷相关的大脑激活与年龄相关的减少。当前的fMRI研究调查了工作记忆中更新机制的大脑激活与年龄相关的差异，而先前的研究并未对此进行研究。通过与混合块/事件相关的设计，该研究能够检查BOLD信号的变化（即神经调节），以增加更新，这是一种尚未充分研究的认知控制方法。将老年人分为年轻组和老年组，以检查在健康衰老过程中，认知控制的神经调节是否随年龄而减少。我们的结果表明，与不需要更新的试验相比，较年轻的成年人在需要更新的试验中更多地激活了左前中央回和右小脑。尽管老年人在这两个区域显示出降低的神经调节作用，但老年队列未能对更新产生任何明显的神经调节作用。此外，老年人不仅在任务执行期间显示出对默认模式网络（DMN）区域的抑制降低，而且还过度激活了某些DMN区域，尤其是。与年轻人相比，年龄较大。老年人在更新过程中在较年轻的成年人中被激活的任务敏感区域的对侧区域（右侧中央前回）也表现出过度激活。脑与行为的相关性表明，这些DMN地区和右前中枢回的年龄相关过度激活对其表现不利。我们的结果表明，在健康的衰老过程中，不仅响应更新需求的神经调节功能减弱，而且老年人在更新过程中还显示出与任务无关的区域的激活不良，并且半球特异性降低。与年轻人相比，这些效应在老年人群中最为明显，这表明在认知控制过程中与年龄相关的神经调节下降在健康衰老中的老年人群中更为明显。老年人在更新过程中，与任务无关的区域的激活也表现出不良适应性增加，并且半球特异性降低。与年轻人相比，这些效应在老年人群中最为明显，这表明在认知控制过程中与年龄相关的神经调节下降在健康衰老中的老年人群中更为明显。老年人在更新过程中，与任务无关的区域的激活也表现出不良适应性增加，并且半球特异性降低。与年轻人相比，这些效应在老年人群中最为明显，这表明在认知控制过程中与年龄相关的神经调节下降在健康衰老中的老年人群中更为明显。