遗忘型轻度认知损伤患者半球间镜像同伦功能连接变化

Homotopic functional connectivity in patients with amnestic mild cognitive impairment

目的采用基于体素的功能同伦(VMHC)方法探讨遗忘型轻度认知损伤(aMCI)患者半球间功能连接变化。方法收集47例aMCI患者(aMCI组)和43名性别、年龄、受教育年限相匹配的正常志愿者(对照组),采集脑结构MRI和静息态fMRI数据;比较aMCI组与对照组间半球间VMHC变化,获得VMHC改变脑区,并以此为种子点,观察与其他脑区间功能连接的异常,并与临床量表评分进行相关性分析。结果 aMCI组患者双侧额下回、前岛叶皮层、壳核VMHC降低,无VMHC增高脑区。aMCI患者前岛叶皮层与默认网络脑区中的后扣带回、内侧前额叶皮层功能连接增加,与注意控制网络脑区、小脑间功能连接减低。左侧前岛叶与内侧前额叶及后扣带回功能连接增加,与患者听觉词语学习测试中再认评分呈正相关(r=0.38、0.33,P均<0.05)。结论 aMCI患者不仅存在半球间VMHC降低,不同脑网络间功能连接亦存在明显差异,对于理解aMCI患者认知改变及其潜在机制具有重要意义。

Objective To observe interhemispheric and interregional resting-state functional connectivity using voxelmirrored homotopic connectivity(VMHC)in patients with amnestic mild cognitive impairment(aMCI).Methods Totally 47 aMCI patients(aMCI group)and 43 gender,age and education matched normal controls(control group)were enrolled.The cranial structural MRI and resting-state fMRI data were collected.VMHC between both groups were compared to obtain the brain areas with altered VMHC.Using the altered VMHC areas as ROIs,the functional connectivity to the whole brain areas was calculated to observe the brain areas with different functional connection.Correlation analysis was performed between altered functional connection and neurocognitive scores.Results aMCI patients showed decreased interhemispheric VMHC primarily at bilateral inferior frontal gyrus,anterior insula and putamen.No area showed increased VMHC was found in aMCI patients.In aMCI patients,the functional connection of anterior insula to default mode network(DMN)regions including the posterior cingulate cortex(PCC)and the medial prefrontal cortex(MPFC)increased,and to attention control network and cerebellum decreased,and the functional connection of the left anterior insula to PCC and MPFC was positively correlated with recognition scores of auditory verbal learning test(r=0.38,0.33,both P<0.05).Conclusion aMCI patients show deficits in inter-hemispheric VMHC and altered functional connection between different brain networks,suggesting an important new avenue for better understanding of the nature of cognitive changes in patients with aMCI.