EEG correlates of time-varying BOLD functional connectivity

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• Resting-state functional connectivity (FC) exhibits dynamic changes over seconds to minutes.
• The neural basis and functional significance of these rapid FC fluctuations remain largely unexplored.
• Understanding these dynamics is crucial for interpreting brain function during rest.

Purpose of the Study:

• To investigate the electrophysiological correlates of time-varying functional connectivity during eyes-closed rest.
• To determine if variations in brain network coupling are associated with concurrent changes in mental state.
• To explore the relationship between EEG oscillations and dynamic FC between major brain networks.

Main Methods:

• Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data were acquired during resting-state conditions.
• A sliding window analysis was applied to assess temporal variations in FC between the default mode network (DMN), dorsal attention network (DAN), and salience network (SN).
• EEG alpha and theta oscillation amplitudes were analyzed to assess mental state variations and their correlation with FC dynamics.

Main Results:

• A significant inverse relationship was observed between alpha power and the strength of connectivity between the DMN and DAN.
• Higher alpha power was associated with a greater spatial extent of anticorrelation between the DMN and DAN.
• Temporal variations in FC between the DAN and DMN showed correlations with EEG alpha oscillation amplitude.

Conclusions:

• The study identified an electrical signature for time-varying functional connectivity between the dorsal attention network and default mode network.
• These findings suggest that dynamic FC fluctuations reflect underlying neural activity and state-dependent variations.
• Electrophysiological measures like alpha oscillations can serve as indicators of dynamic network interactions in the brain.