Current source density analysis of resting state EEG in depression: a review

Area of Science:

• Neuroscience
• Psychiatry
• Biomedical Engineering

Background:

• Electroencephalography (EEG) is a key tool for investigating major depressive disorder (MDD).
• Current Source Density (CSD) analysis, a method assessing extracellular current sources, has gained prominence in neurophysiological research over the last two decades.
• CSD analysis offers insights into the local neuronal generators of brain activity.

Purpose of the Study:

• To review the existing literature on resting-state CSD analysis in patients diagnosed with MDD.
• To identify prominent findings related to clinical endophenotypes and treatment outcome prediction using CSD in MDD.
• To highlight potential inconsistencies and areas for future research.

Main Methods:

• Systematic review of published studies employing resting-state CSD analysis in MDD.
• Analysis of findings concerning specific EEG frequency bands (e.g., alpha, theta) and brain regions (e.g., frontal, rostral anterior cingulate gyrus).
• Examination of CSD's utility in identifying patient subgroups and predicting treatment response.

Main Results:

• Increased resting-state alpha band CSD in frontal regions is a common finding in MDD patients.
• Elevated theta band activity in the rostral anterior cingulate gyrus (rACC) is associated with a positive response to antidepressant treatment.
• Methodological variations across studies may contribute to conflicting results.

Conclusions:

• Resting-state CSD analysis provides valuable neurophysiological markers for MDD.
• CSD shows potential for identifying clinical endophenotypes and predicting treatment outcomes in depression.
• Further standardized research is necessary to differentiate MDD from other psychiatric disorders and healthy controls.