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Alzheimer's disease and amnestic mild cognitive impairment weaken connections within the default-mode network: a

David C Zhu1, Shantanu Majumdar, Igor O Korolev

  • 1Department of Radiology, Michigan State University, East Lansing, MI 48824, USA. zhuda@msu.edu

Journal of Alzheimer'S Disease : JAD
|January 15, 2013
PubMed

Insights

Alzheimer's disease (AD) and mild cognitive impairment (MCI) weaken brain connections in the default-mode network (DMN). This study used advanced imaging to reveal these structural and functional changes, offering insights into neurodegenerative disease progression.

Area of Science:

  • Neuroimaging
  • Neurodegenerative Diseases
  • Cognitive Science

Background:

  • Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) are characterized by progressive cognitive decline.
  • The default-mode network (DMN) is implicated in cognitive function and is known to be affected in neurodegenerative conditions.
  • Understanding the specific alterations within the DMN is crucial for early diagnosis and treatment development.

Purpose of the Study:

  • To investigate structural and functional changes in the DMN in patients with AD and aMCI using a multi-modal imaging approach.
  • To compare DMN connectivity in AD, aMCI, and normal controls (NC).
  • To explore the relationship between DMN alterations and disease progression.

Main Methods:

  • Multi-modal neuroimaging including resting-state functional MRI, diffusion-weighted MRI, volumetric MRI, and FDG-PET.
  • Functional and structural connectivity analyses of the DMN using the isthmus of the cingulate cortex (ICC) as a seed region.
  • Comparison of imaging data across three groups: probable AD, aMCI, and normal controls (NC).

Main Results:

  • Alzheimer's disease (AD) significantly weakens both structural and functional connections within the default-mode network (DMN).
  • These DMN alterations correlate with reduced metabolic activity and regional atrophy observed via FDG-PET and volumetric MRI.
  • A trend of progressive DMN connection weakening was observed from normal controls (NC) to aMCI and then to AD, though not statistically significant between aMCI and the other groups.

Conclusions:

  • The default-mode network (DMN) serves as a key indicator of brain changes in Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI).
  • Multi-modal imaging reveals significant structural and functional disruptions in the DMN associated with AD.
  • The findings highlight the DMN's role in the progression of cognitive impairment and dementia.

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