Electroencephalogram Gamma Band Power Correlates with Anhedonia in a Community Sample

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers

Background:

• Major depression (MD) is a heterogeneous condition lacking objective diagnostic tools.
• Current diagnostic methods rely on subjective symptom reporting.
• Electroencephalogram (EEG) gamma band activity is implicated in cognition and reward processing, suggesting its potential as a biomarker.

Purpose of the Study:

• To investigate the relationship between resting-state gamma band power and major depression (MD).
• To explore the association between gamma band power and four distinct depressive subtypes: anhedonia, cognitive-depression, somatic-depression, and depressed mood.

Main Methods:

• A correlative study involving 100 participants (depressed and non-depressed).
• Resting-state EEG data analyzed using exact standardized low-resolution electromagnetic tomography (eLORETA).
• Gamma band power correlated with Zung Self-rating Depression Scale (SDS) scores.

Main Results:

• No significant correlation was found between overall depression scores and gamma band power.
• A significant positive correlation emerged between anhedonia and gamma band power, particularly in the left anterior cingulate cortex.
• Other significant areas included the posterior cingulate cortex and left middle/superior frontal cortex.

Conclusions:

• Preliminary evidence supports gamma band power as a potential neurophysiological indicator for depressive subtypes.
• Findings may inform future diagnostic and treatment strategies for depression and its subtypes.
• The link between anhedonia and gamma band power suggests dysfunction in reward processing.