Spatiotemporal Oscillatory Patterns During Working Memory Maintenance in Mild Cognitive Impairment and Subjective...

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Working memory (WM) is vital for cognition and its decline is an early Alzheimer's disease symptom.
• Mild cognitive impairment (MCI) shows WM alterations, but research on subjective cognitive decline (SCD) is limited.

Purpose of the Study:

• To investigate neural differences in working memory maintenance between MCI, SCD, and healthy elders using magnetoencephalography (MEG).
• To identify specific oscillatory patterns and brain regions associated with cognitive decline stages.

Main Methods:

• Magnetoencephalography (MEG) was employed during a working memory task in three groups: MCI, SCD, and healthy elders.
• Time-frequency analysis and source localization were used to analyze oscillatory differences during the WM maintenance period (0-4000 ms).

Main Results:

• Significant group differences were found in theta, alpha, and beta bands during early (250-1250 ms) and late (2750-3750 ms) maintenance.
• MCI patients displayed reduced fronto-temporal synchronization in early theta-alpha and late theta bands, and reduced temporo-posterior power in the early beta band compared to controls and SCD.
• Early theta-alpha power correlated with memory scores; late theta power correlated with task performance and functional activity.

Conclusions:

• Neural network damage in MCI may manifest as reduced synchronization in specific frequency bands during working memory tasks.
• These findings highlight distinct neurophysiological profiles of MCI and SCD, offering potential biomarkers for early detection of cognitive impairment.