Aperiodic neural activity is a biomarker for depression severity

Area of Science:

• Neuroscience
• Computational psychiatry
• Biomarker discovery

Background:

• Major Depressive Disorder (MDD) lacks reliable physiological biomarkers, hindering treatment optimization.
• Current outcome measures for MDD show significant variability.
• A need exists for objective measures to track mood changes and treatment response in real-time.

Approach:

• Utilized intracranial electroencephalography (EEG) recordings from the ventromedial prefrontal cortex (VMPFC) in patients undergoing deep brain stimulation (DBS) for treatment-resistant depression (TRD).
• Analyzed the aperiodic component of the power spectral density (PSD) as a proxy for neural excitation-inhibition balance.
• Correlated changes in the aperiodic slope with clinical depression severity scores.

Key Points:

• The aperiodic slope of the PSD in the VMPFC significantly correlated with depression severity in N=5 subjects.
• Flatter (less negative) aperiodic slopes were associated with reduced depression severity.
• This finding suggests the aperiodic slope can serve as a passive biomarker for mood fluctuations.

Conclusions:

• The aperiodic slope in the VMPFC is a promising physiological biomarker for tracking mood changes in MDD.
• This biomarker has the potential to facilitate individualized treatment strategies for MDD.
• Future applications may include both invasive and non-invasive monitoring for treatment response.