Disconnection of alpha oscillations within default mode network associated with memory dysfunction in amnestic MCI

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Episodic memory impairment is a hallmark of amnestic mild cognitive impairment (aMCI).
• Alterations in the default mode network (DMN) functional connectivity (FC) are implicated in aMCI, but specific oscillatory dynamics remain underexplored.

Purpose of the Study:

• To comprehensively investigate resting-state FC across various oscillations within the DMN in aMCI patients.
• To examine the association between DMN FC and episodic memory performance in aMCI.

Main Methods:

• Resting-state magnetoencephalography (MEG) recordings were performed on 30 aMCI patients and 26 healthy controls (HC).
• Spectral powers, peak frequencies, and DMN FC were compared between groups.
• Correlations between FC values and memory performance were analyzed.

Main Results:

• No significant differences in spectral powers or peak frequencies were found in regional nodes between groups.
• aMCI patients exhibited significantly reduced alpha-band FC compared to HC.
• Lower alpha-band FC between medial temporal cortex and posterior cingulate cortex/precuneus correlated with poorer memory recall.

Conclusions:

• Aberrant DMN connectivity, specifically in the alpha frequency band, may serve as a neural biomarker for episodic memory deficits in aMCI.
• Findings suggest potential targets for brain stimulation therapies aimed at managing memory impairments in aMCI.