Estimation of the cortical functional connectivity by directed transfer function during mental fatigue

Area of Science:

• Neuroscience
• Cognitive Science
• Signal Processing

Background:

• Mental fatigue impacts cognitive performance and brain function.
• Understanding brain network dynamics during fatigue is crucial for cognitive health.
• Previous methods have limitations in characterizing directed information flow.

Purpose of the Study:

• To investigate changes in functional brain connectivity due to mental fatigue using the directed transfer function (DTF) method.
• To characterize the direction and strength of information flow between cortical areas during sustained cognitive tasks.
• To explore the relationship between DTF measures and mental fatigue levels.

Main Methods:

• Utilized the directed transfer function (DTF) method on electroencephalography (EEG) data.
• Analyzed EEG frequency bands: total (0.5-30 Hz), alpha (8-12 Hz), and beta (13-30 Hz).
• Compared functional coupling patterns in pre-task and post-task periods to assess fatigue-induced changes.

Main Results:

• Observed a shift from parietal-to-frontal to frontal-to-parietal coupling in the total EEG band after tasks.
• Increased mental fatigue weakened parietal-to-frontal alpha coupling and altered beta band coupling.
• Enhanced frontal-to-center and middle-to-hemispheric couplings were noted in specific frequency bands and hemispheres.

Conclusions:

• The DTF method effectively reveals changes in directed information flow associated with mental fatigue.
• Functional coupling in frontal, central, and parietal areas is strongly correlated with the wake-fatigue transition.
• DTF offers a promising approach for studying mental fatigue and brain network alterations.