Aberrant Functional Connectivity Architecture in Alzheimer's Disease and Mild Cognitive Impairment: A Whole-Brain,...

Area of Science:

• Neuroscience
• Medical Imaging
• Cognitive Science

Background:

• Alzheimer's disease (AD) and mild cognitive impairment (MCI) represent a spectrum of neurodegenerative disorders.
• Understanding the neural underpinnings of cognitive decline is crucial for early diagnosis and intervention.
• Whole-brain functional connectivity alterations are increasingly recognized as potential biomarkers.

Purpose of the Study:

• To investigate alterations in whole-brain functional connectivity patterns in relation to disease severity in Alzheimer's disease (AD) and mild cognitive impairment (MCI).
• To explore the relationship between functional connectivity strength and cognitive status as measured by the Mini-Mental State Examination (MMSE).

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) data were collected from 27 MCI subjects, 35 AD patients, and 27 healthy controls (NC).
• Interregional functional connectivity was assessed across 90 predefined brain regions.
• Connectivity differences between AD and NC groups were analyzed, and correlations with MMSE scores were evaluated in MCI and AD groups.

Main Results:

• Alzheimer's disease patients exhibited significantly decreased whole-brain functional connectivity compared to normal cognition controls.
• Key affected regions included nodes of the default mode network and temporal lobe structures.
• Functional connectivity changes were significantly associated with disease severity and cognitive impairment in both AD and MCI groups.

Conclusions:

• The study provides evidence for widespread functional connectivity disruptions in Alzheimer's disease and mild cognitive impairment.
• These connectivity alterations are linked to disease severity, suggesting their potential as biomarkers.
• Findings contribute to understanding the neural basis of AD and MCI and will aid future meta-analyses.