EEG default mode network in the human brain: spectral regional field powers

Area of Science:

• Neuroscience
• Electrophysiology
• Brain Activity

Background:

• Resting-state brain activity is crucial for understanding cognitive function.
• While fMRI has identified a default mode network, comprehensive electrophysiological correlates are less understood.
• Electroencephalography (EEG) offers high temporal resolution for studying brain dynamics.

Purpose of the Study:

• To investigate the spatial characteristics of spectral distribution in EEG field powers during eyes-closed (EC) and eyes-open (EO) resting states.
• To identify distinct electrophysiological patterns associated with different resting states.
• To establish a baseline EEG-DMN for evaluating brain function.

Main Methods:

• High-density 128-channel EEG was recorded from 15 healthy female college students during 3-minute EC and EO resting states.
• Fast Fourier Transform (FFT) signal analysis was employed to examine spectral power distribution.
• Regions of interest were defined by 90% of the spectral effective value to capture dominant brain activity fields.

Main Results:

• Low-frequency delta EEG power expanded spatially and increased in the prefrontal area from EC to EO.
• Theta power decreased significantly and shifted frontally from EC to EO.
• Alpha and beta EEG powers decreased significantly over posterior areas from EC to EO, while high-frequency beta and gamma bands showed no change.
• Significant correlations between EC and EO states were found for delta and theta band powers.
• Inter-individual variability in regional power was higher in the EC state.

Conclusions:

• Distinct spectral EEG field power patterns characterize EC and EO resting states.
• These findings define the electrophysiological basis of the resting-state EEG default mode network (EEG-DMN).
• The EEG-DMN serves as a valuable baseline for assessing brain function, developmental changes, and dysfunction in disease.