title: Default Mode Network Functional Connectivity in Early and Late Mild Cognitive Impairment: Results From the Alzheimer's Disease Neuroimaging Initiative.
abstract: Default mode network (DMN) functional connectivity is one of the neuroimaging candidate biomarkers of Alzheimer disease. However, no studies have investigated DMN connectivity at different stages of mild cognitive impairment (MCI). The aim of this study was to investigate patterns of DMN connectivity and its breakdown among cognitively normal (CN), early MCI (EMCI), and late MCI (LMCI) subjects.
  
  
  
  Magnetic resonance imaging data and neuropsychological test scores from 130 subjects (CN=43, EMCI=47, LMCI=40) were obtained from the Alzheimer's Disease Neuroimaging Initiative. DMN functional connectivity was extracted using independent components analysis and compared between groups.
  
  
  
  Functional connectivity in the precuneus, bilateral medial frontal, parahippocampal, middle temporal, right superior temporal, and left angular gyri was decreased in EMCI subjects compared with CN subjects. When the 2 MCI groups were directly compared, LMCI subjects exhibited decreased functional connectivity in the precuneus, bilateral medial frontal gyri, and left angular gyrus. There was no significant difference in gray matter volume among the 3 groups. Amyloid-positive EMCI subjects revealed more widespread breakdown of DMN connectivity than amyloid-negative EMCI subjects. A quantitative index of DMN connectivity correlated well with measures of cognitive performance.
  
  
  
  Our results suggest that the breakdown of DMN connectivity may occur in the early stage of MCI.
authors: *Graduate School of Medical Science and Engineering †Laboratory for Cognitive Neuroscience and NeuroImaging, Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology ‡Department of Neurology, Konyang University Hospital, College of Medicine, Konyang University, Daejeon, Republic of Korea.
authors: Eek-Sung
authors: ES
authors: Lee
authors: Kwangsun
authors: K
authors: Yoo
authors: Young-Beom
authors: YB
authors: Lee
authors: Jinyong
authors: J
authors: Chung
authors: Ji-Eun
authors: JE
authors: Lim
authors: Bora
authors: B
authors: Yoon
authors: Yong
authors: Y
authors: Jeong
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D000682:Amyloid; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data
chemical_list: D000682:Amyloid