Dynamic Alterations of Functional Systems in Alzheimer's Disease: A Co-Activation Pattern Analysis

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Resting-state brain dysfunction is known in Alzheimer's disease (AD), but dynamic functional system changes are unclear.
• Understanding these dynamic alterations is crucial for diagnosing and treating AD spectrum disorders.

Purpose of the Study:

• To investigate dynamic functional brain alterations in individuals with mild cognitive impairment (MCI) and AD.
• To characterize the topological properties of brain functional states using graph theory.

Main Methods:

• Co-activation pattern (CAP) analysis was used on resting-state fMRI data from 243 participants.
• Graph theory analysis was applied to assess topological properties of identified brain states.
• Brain states were defined by dominant functional networks, including the default mode network, dorsal attention network (DAN), and others.

Main Results:

• Five distinct brain states were identified, with State 3 (default mode and central executive networks) showing reduced persistence and resilience in MCI and AD groups.
• MCI and AD groups exhibited altered state transitions, including decreased transitions from State 2 to State 5 and reduced self-transitions within State 3.
• Graph theory analysis revealed altered network topology in MCI and AD, with increased node centrality and efficiency in certain regions, correlating with CAP findings.

Conclusions:

• Dynamic functional state instability is linked to static network reorganization in the AD spectrum.
• These findings offer a multiscale framework for understanding cognitive decline in AD and related disorders.
• The study highlights the importance of dynamic functional analysis in neurodegenerative diseases.