title: Structural and functional brain changes in the default mode network in subtypes of amnestic mild cognitive impairment.
abstract: BACKGROUND
  Various amnestic mild cognitive impairment (aMCI) subtypes have been identified as single domain (SD) or multiple domain (MD), with differential probabilities of progression to Alzheimer disease (AD). Detecting the differences in the alterations in gray matter (GM) and intrinsic brain activity between the subtypes of aMCI help to understand their pathophysiological mechanisms and was conducive to construct such potential biomarkers to monitor the progression of aMCI.
  
  
  METHODS
  In all, 22 normal controls (NCs), 18 patients with SD-aMCI, and 17 patients with MD-aMCI participated in the study. The amplitude of low-frequency fluctuations (ALFFs) during rest represented intrinsic brain activity. Voxel-based morphometry analysis was used to measure the GM volume.
  
  
  RESULTS
  The MD-aMCI showed reduced GM in hippocampus (Hip), parahippocampal gyrus (PHG), and other regions than SD-aMCI. The SD-aMCI had reduced GM only in Hip and PHG than in NC. The MD-aMCI showed decreased ALFF in posterior cingulate cortex (PCC) and precuneus and increased ALFF in anterior cingulate cortex (ACC), PHG, and Hip compared with both SD-aMCI and NC. However, no ALFF difference was found between SD-aMCI and NC. Neuropsychological measures were correlated with ALFF in PCC and ACC only in the MD-aMCI.
  
  
  CONCLUSIONS
  Patients with MD-aMCI displayed more severe GM atrophy and ALFF changes than patients with SD-aMCI. The results suggested that aMCI is heterogeneous and that MD-aMCI may be a prodromal stage which is more close to AD.
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Miao
authors.initials: M
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Junying
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China Banner Alzheimer's Institute, Phoenix, AZ, USA.
authors.forename: Kewei
authors.initials: K
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Yaojing
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.affiliation: Banner Alzheimer's Institute, Phoenix, AZ, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Fleisher
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China.
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, PR China zhang_rzs@bnu.edu.cn.
authors.forename: Zhanjun
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000544:Alzheimer Disease; D000647:Amnesia / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
keywords: gray matter volume; mild cognitive impairment; resting-state functional MRI; spontaneous brain activity