Aberrant E-I Balance and Brain Criticality in Major Depressive Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Complex Systems

Background:

• Brain criticality and complexity are emerging biomarkers for psychiatric disorders.
• Major Depressive Disorder (MDD) is associated with disordered neural dynamics, though their specifics are unclear.

Purpose of the Study:

• Investigate brain criticality, excitation-inhibition (E/I) balance, E+I strength, and complexity in MDD.
• Identify potential EEG-based biomarkers for MDD.

Main Methods:

• Resting-state EEG data from 183 MDD patients and 133 healthy controls (HC).
• Analysis of amplitude bistability, long-range temporal correlations, E/I ratios, and E+I strength.
• Classification using least absolute shrinkage and selection operator (LASSO) regression.

Main Results:

• MDD patients exhibited reduced amplitude bistability and weaker long-range temporal correlations, indicating a deviation from criticality.
• Frequency-specific alterations in E/I ratios and E+I strength were observed in MDD.
• LASSO regression achieved high accuracy using criticality, E/I, and E+I measures.

Conclusions:

• Brain dynamics in MDD deviate from criticality and show specific excitation-inhibition imbalances.
• These complex system alterations provide a fingerprint for MDD.
• Findings support the development of novel biomarkers for MDD diagnosis and treatment.