Wang Pengyun, Li Rui, Yu Jing, Huang Zirui, Yan Zhixiong, Zhao Ke, Li Juan
Center on Aging Psychology, CAS Key Laboratory of Mental Health, Institute of PsychologyBeijing, China.
Department of Psychology, University of Chinese Academy of SciencesBeijing, China.
Front Behav Neurosci. 2017 Sep 22;11:174. doi: 10.3389/fnbeh.2017.00174. eCollection 2017.
Few studies to date have investigated the background network in the cognitive state relying on executive function in mild cognitive impairment (MCI) patients. Using the index of degree of centrality (DC), we explored distant synchronization of background network in MCI during a hybrid delayed-match-to-sample task (DMST), which mainly relies on the working memory component of executive function. We observed significant interactions between group and cognitive state in the bilateral posterior cingulate cortex (PCC) and the ventral subregion of precuneus. For normal control (NC) group, the long distance functional connectivity (FC) of the PCC/precuneus with the other regions of the brain was higher in rest state than that working memory state. For MCI patients, however, this pattern altered. There was no significant difference between rest and working memory state. The similar pattern was observed in the other cluster located in the right angular gyrus. To examine whether abnormal DC in PCC/precuneus and angular gyrus partially resulted from the deficit of FC between these regions and the other parts in the whole brain, we conducted a seed-based correlation analysis with these regions as seeds. The results indicated that the FC between bilateral PCC/precuneus and the right inferior parietal lobule (IPL) increased from rest to working memory state for NC participants. For MCI patients, however, there was no significant change between rest and working memory state. The similar pattern was observed for the FC between right angular gyrus and right anterior insula. However, there was no difference between MCI and NC groups in global efficiency and modularity. It may indicate a lack of efficient reorganization from rest state to a working memory state in the brain network of MCI patients. The present study demonstrates the altered distant synchronization of background network in MCI during a task relying on executive function. The results provide a new perspective regarding the neural mechanisms of executive function deficits in MCI patients, and extend our understanding of brain patterns in task-evoked cognitive states.
迄今为止，很少有研究调查轻度认知障碍（MCI）患者在依赖执行功能的认知状态下的背景网络。我们使用中心度指数（DC），在一个主要依赖执行功能的工作记忆成分的混合延迟匹配样本任务（DMST）中，探究了MCI患者背景网络的远距离同步。我们观察到双侧后扣带回皮质（PCC）和楔前叶腹侧亚区在组与认知状态之间存在显著交互作用。对于正常对照组（NC），PCC/楔前叶与大脑其他区域的长距离功能连接（FC）在静息状态下高于工作记忆状态。然而，对于MCI患者，这种模式发生了改变。静息状态和工作记忆状态之间没有显著差异。在位于右侧角回的另一个簇中也观察到了类似模式。为了检查PCC/楔前叶和角回中异常的DC是否部分源于这些区域与全脑其他部分之间FC的缺陷，我们以这些区域为种子进行了基于种子的相关性分析。结果表明，对于NC参与者，双侧PCC/楔前叶与右下顶叶小叶（IPL）之间的FC从静息状态到工作记忆状态增加。然而，对于MCI患者，静息状态和工作记忆状态之间没有显著变化。右侧角回与右侧前岛叶之间的FC也观察到了类似模式。然而，MCI组和NC组在全局效率和模块化方面没有差异。这可能表明MCI患者大脑网络从静息状态到工作记忆状态缺乏有效的重组。本研究证明了在依赖执行功能的任务中MCI患者背景网络的远距离同步改变。这些结果为MCI患者执行功能缺陷的神经机制提供了新的视角，并扩展了我们对任务诱发认知状态下脑模式的理解。
