Abnormal resting state effective connectivity within the default mode network in major depressive disorder: A...

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Major Depressive Disorder (MDD) is a prevalent mental health condition.
• Aberrant activation and functional connectivity of the Default Mode Network (DMN) are hallmarks of MDD.
• Effective connectivity within the DMN in MDD remains largely unexplored.

Purpose of the Study:

• To investigate alterations in effective connectivity within the DMN in MDD patients.
• To examine changes in DMN effective connectivity before and after antidepressant treatment.

Main Methods:

• Utilized Group Independent Component Analysis (GICA) to define DMN regions.
• Employed spectral Dynamic Causal Modeling (DCM) to estimate causal interactions between DMN regions.
• Analyzed resting-state fMRI data from 27 MDD patients and 27 healthy controls.

Main Results:

• MDD patients exhibited reduced influence from the left parietal cortex to other DMN regions compared to controls.
• Antidepressant treatment led to a significant decrease in the influence from the right parietal cortex to the posterior cingulate cortex.

Conclusions:

• Reduced excitatory causal influence from the left parietal cortex is a critical DMN alteration in MDD.
• Disrupted causal influences within the parietal cortex-posterior cingulate cortex pathway are responsive to antidepressant therapy.