Abstract：
Working memory (WM) impairment has been well characterized in normal aging. Various studies have explored changes in either the regional activity or the interregional connectivity underlying the aging process of WM. We proposed that brain activity and connectivity would independently alter with aging and affect WM performance. WM was assessed with a classical N-back task during functional magnetic resonance imaging in a community-based sample comprising 168 elderly subjects (aged 55-86 years old). Following the rationale of background functional connectivity, we assessed age-related alterations in brain activity and seed-based interregional connectivity independently. Analyses revealed age-related decrease in positive activity of the inferior parietal lobule (IPL) and an increase in the negative activity of the ventral anterior cingulate cortex (ACC), and the local functional dysfunctions were accompanied by alterations in their connectivity to other cortical regions. Importantly, regional activity impairments in the IPL and ACC could mediate age-related effects on accuracy rate and reaction time, respectively, and those effects were further counterbalanced by enhancement of their background functional connectivity. We thus claimed that age-induced alterations in regional activity and interregional connectivity occurred independently and contributed to WM changes in aging. Our findings presented the way brain activity and functional connectivity interact in the late adulthood, thus providing a new perspective for understanding WM and cognitive aging.
摘要：
工作记忆（WM）障碍在正常衰老中已得到很好的表征。各种研究都探讨了WM老化过程中区域活动或区域间连通性的变化。我们提出大脑活动和连通性会随着年龄的增长而独立改变并影响WM性能。在包括168名老年受试者（年龄55-86岁）的社区样本中，在功能磁共振成像期间，通过经典的N-back任务评估了WM。根据后台功能连接的基本原理，我们独立评估了与年龄相关的脑活动改变和基于种子的区域间连通性.分析显示，与年龄相关的下顶叶小叶（IPL）的阳性活动减少，腹前扣带回皮质（ACC）的阴性活动增加，局部功能失调伴随着它们与其他皮质区域的连通性的改变。重要的是,IPL和ACC中的区域活动障碍可以介导与年龄相关的对准确率和反应时间的影响，分别,这些影响通过增强其背景功能连通性进一步抵消。因此，我们声称年龄引起的区域活动和区域间连通性的变化是独立发生的，并导致了WM衰老的变化。我们的发现展示了大脑活动和功能连接在成年后期相互作用的方式，从而为理解WM和认知衰老提供了新的视角。
