Objective To explore the default mode network in mild cognitive impairment(MCI) by restingstate fmri and compare the cognitive functions.Methods 16 old cases with mild cognitive impairment and 16 normal elders were tested by resting-state functional mri and ICA analysis.The abnormal areas were explored by the functional connectivity analysis of the whole brain.Results The default mode network areas were mainly as follows:marginal gyrus,precuneus,posterior cingulate cortex,medial prefrontal cortex,calcarine sulcus,inferior parietal lobule,occipital lobe and precentral gyrus.Compred the areas and results showed the functional connectivities of MCI group decreased in Precuneus-L,Calcarine-L (R),Cingulum-Mid-L,Angular-L and Frontal-Mid-R than those of controls(P ＜ 0.01).The areas where the functional connectivities of MCI group increased were Precuneus R and Middle Temporal Gyrus (P ＜ 0.01).Conclusion There were abnormal default mode network in mild cognitive impairment patients,meanwhile the significant changes might be related to the pathological mechanism.%目的 探讨在静息状态下轻度认知障碍(mild cognitive impairment,MCI)患者大脑默认网络(default mode network,DMN)的特点.方法 采用功能核磁共振成像(functional magnetic resonance imaging,FMRI)技术,对16例轻度认知障碍患者及17例正常老龄化老人进行静息状态下全脑功能核磁共振扫描,采用独立成分分析(independent component analysis,ICA)的方法分别提取其静息态下的大脑默认网络,进行功能连接的比较.结果 提取出的默认网络主要脑区如下:边缘叶、楔前叶、后扣带回、内侧前额叶、距状沟、顶下小叶、枕叶、中央前回.对比后发现轻度认知障碍组较正常老化组功能连接减弱的脑区有:左侧楔前叶、双侧距状叶、左侧中扣带回、左侧角回和右侧额中回(P＜0.01)；功能连接增强的脑区有:右侧楔前叶和左侧颞中回(P＜0.01).结论 轻度认知障碍患者静息态大脑默认网络存在异常,这些异常改变可能与其病理机制有关,并为其诊断提供参考.
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