Analysis Of Association Between CHRNA7 Gene Polymorphism And Default Mode Network In Amnestic Mild Cognitive Impairment

Backgroud Alzheimer’s disease (AD) is a neurodegenerative diseases characterized by a progressive decline in cognitive function. Mild congtive impairment (MCI) refers to patients with memory or cognitive impairment, but has no appreciable effect on the daily. MCI has not reached the degree of dementia, is an intermediate state between normal aging and dementia. According to cognitive involvement, it can be divided into amnestic mild congtive impairment (aMCI) and non-amnestic mild congtive impairment (naMCl). aMCI has been confirmed to be the high-risk group for Alzheimer’s disease. But the etiology and pathogenesis of AD is unknown at present, and how to go from early recognition and active intervention is the research emphasis of the AD. At this stage, the characteristics of resting function is a hot topic in AD research, and has been madesignificant progress.The study found that default network activities between MCI patients with normal aging peers are different, mainly reduce the activity within the network function connection increase, the brain area local consistency increase, decrease low-frequency amplitude, etc. Exploring the impact of gene polymorphism on aMCI CHRNA7 default network will be capabilities for early diagnosis and timely intervention, delaying the progression of great significance.Purpose To explore the influence of CHRNA7 rs8027814 gene polymorphism on localized brain activity of resting state in aMCI patients.Methods In our study, we recruited the aMCI patients and well matched controls with age, gender and education. Full-scale neuropsychological tests were used to evaluate thecognitive function in these subjects, including MMSE score, DRS score, episodic memory, visuospatial function, information processing speed and executive function. In this article, we discribe the aMCI group and HC group inclusion and exclusion criteria, CHRNA7 gene polymorphism, neuropsychological assemet, grouping criteria, fMRI scanning procedure and parameters, etc. Preprocessing all the image data, respectively extract the default mode network (DMN) time series for region of interst (ROI). Analyse influence of CHRNA7 rs8027814 gene polymorphism in DMN function connection in aMCI. Use the post-hoc test to further duscuss region of diseasexgene interaction and analyse combined with cognitive function.Result 1. The default network activation under different condition:(1) Main effect of gene: left posterior cingulate cortex (PCC), bilateral precuneus, right cuneus, bilateral superior frontal gyrus, bilateral middle frontal gyrus. (2) Main effect of disease:bilateral precuneus, left posterior cingulate cortex (PCC). (3) Main effect of diseasexgene:bilateral precuneus, left posterior cingulate cortex (PCC).2. Differents of function connection in different groups:(1) Trends of the direction:DMN with posterior cingulate cortex and precuneus positive direction, and aMCI group show lower FC than HC group. (2) In group:In PCC/Pcu GG genotype carriers express lower FC than AG/AA carriers in aMCI group. (3) Between-group:In PCC/Pcu aMCI group GG genotype carriers show lower FC than HC group.3. Relativity analysis:(1) In aMCI group GG genotype carriers, the FC of PCC positive correlation with attention in DRS score (P= 0.042, r= 0.282). (2) In aMCI group GG genotype carriers, the FC of PCC positive correlation with ALVT-20min score in episodic memory (P= 0.015, r= 0.337). (3) In aMCI group AG/AA genotype carriers, the FC of PCC negative with Rey-Osterrieth Complex Figure Test-20-minute delayed recall (CFT-20min DR) in episodic memory (P= 0.012, r=-0.516), in HC group (P= 0.044, r=-0.28)Conclusion CHRNA7 rs8027814 gene polymorphism widespread arouse abnormal DMN function connection. These FC involved in posterior cingulate cortex and precuneus. The experiment suggest that CHRNA7 rs8027814 gene polymorphism selective damage resting state network in aMCI, and participate in aMCI pathological process.