title: Specifically progressive deficits of brain functional marker in amnestic type mild cognitive impairment.
abstract: BACKGROUND
  Deficits of the default mode network (DMN) have been demonstrated in subjects with amnestic type mild cognitive impairment (aMCI) who have a high risk of developing Alzheimer's disease (AD). However, no longitudinal study of this network has been reported in aMCI. Identifying links between development of DMN and aMCI progression would be of considerable value in understanding brain changes underpinning aMCI and determining risk of conversion to AD.
  
  
  RESULTS
  Resting-state fMRI was acquired in aMCI subjects (n = 26) and controls (n = 18) at baseline and after approximately 20 months follow up. Independent component analysis was used to isolate the DMN in each participant. Differences in DMN between aMCI and controls were examined at baseline, and subsequent changes between baseline and follow-up were also assessed in the groups. Posterior cingulate cortex/precuneus (PCC/PCu) hyper-functional connectivity was observed at baseline in aMCI subjects, while a substantial decrement of these connections was evident at follow-up in aMCI subjects, compared to matched controls. Specifically, PCC/PCu dysfunction was positively related to the impairments of episodic memory from baseline to follow up in aMCI group.
  
  
  CONCLUSIONS
  The patterns of longitudinal deficits of DMN may assist investigators to identify and monitor the development of aMCI.
authors.affiliation: Medical School of Southeast University, Nanjing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Bai
authors.forename: David R
authors.initials: DR
authors.lastname: Watson
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Shi
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Chunxian
authors.initials: C
authors.lastname: Yue
authors.lastname: YuhuanTeng
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Yonggui
authors.initials: Y
authors.lastname: Yuan
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000647:Amnesia / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male