Decreased activity with increased background network efficiency in amnestic MCI during a visuospatial working memory task
Decreased activity with increased background network efficiency in amnestic MCI during a visuospatial working memory task
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DOI：
10.1002/hbm.22851
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发表时间：
2015-09-01
影响因子：
4.8
通讯作者：
Lam, Linda C. W.
中科院分区：
文献类型：
--
作者：
Lou, Wutao;Shi, Lin;Lam, Linda C. W.
最近的研究表明，遗忘性轻度认知障碍（aMCI）患者存在工作记忆障碍。然而，aMCI 工作记忆缺陷的神经生理学基础尚不清楚。本研究的目的是探讨aMCI中编码和识别过程中的异常活动，以及维持工作记忆状态的后台网络的重组。在具有三个识别难度级别的视觉空间工作记忆任务中使用事件相关的功能磁共振成像，研究了 17 名 aMCI 患者和 19 名匹配对照者的背景网络的任务相关激活和网络效率。与认知健康的对照组相比，aMCI 患者在编码阶段的额叶和视觉皮层活动显着降低，而在识别阶段，额叶、顶叶和视觉区域的活动显着降低。此外，在 aMCI 患者的背景网络中也观察到局部效率的提高。结果表明，aMCI患者在视觉空间工作记忆任务中表现出编码和识别功能受损，并且可能需要付出更多努力来维持认知状态。这项研究拓展了我们对aMCI工作记忆功能受损的认识，并为研究aMCI的代偿机制提供了新的视角。 Hum Brain Mapp 36:3387-3403, 2015。(c) 2015 Wiley periodicals, Inc.
Recent studies have demonstrated the working memory impairment in patients with amnestic mild cognitive impairment (aMCI). However, the neurophysiological basis of the working memory deficit in aMCI is poorly understood. The aim of this study was to explore the abnormal activity during encoding and recognition procedures, as well as the reorganization of the background network maintaining the working memory state in aMCI. Using event-related fMRI during a visuospatial working memory task with three recognition difficulty levels, the task-related activations and network efficiency of the background network in 17 aMCI patients and 19 matched controls were investigated. Compared with cognitively healthy controls, patients with aMCI showed significantly decreased activity in the frontal and visual cortices during the encoding phase, while during the recognition phase, decreased activity was detected in the frontal, parietal, and visual regions. In addition, increased local efficiency was also observed in the background network of patients with aMCI. The results suggest patients with aMCI showed impaired encoding and recognition functions during the visuospatial working memory task, and may pay more effort to maintain the cognitive state. This study extends our understanding of the impaired working memory function in aMCI and provides a new perspective to investigate the compensatory mechanism in aMCI. Hum Brain Mapp 36:3387-3403, 2015. (c) 2015 Wiley Periodicals, Inc.