Large-scale structural network change correlates with clinical response to rTMS in depression

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Repetitive transcranial magnetic stimulation (rTMS) efficacy in major depressive disorder (MDD) varies, with underlying neural mechanisms involving large-scale brain networks.
• The relationship between structural network integrity, plasticity, and rTMS response in MDD remains unclear.

Purpose of the Study:

• To investigate the association between structural brain networks and clinical response to rTMS in MDD patients.
• To explore the neural mechanisms of rTMS therapy by analyzing structural covariance networks (SCNs).

Main Methods:

• Structural MRI data from 268 MDD patients and 70 healthy controls from the THREE-D trial were analyzed.
• Multivariate analyses characterized SCNs from cortical gray matter thickness, volume, and surface area.
• Association between pre-treatment SCNs and clinical improvement was assessed, along with post-treatment changes.

Main Results:

• Cortical thickness and volume SCNs differentiated MDD patients from controls (p=0.005).
• No significant association was found between pre-treatment SCNs and clinical improvement.
• An anticorrelated SCN between the left dorsolateral prefrontal cortex (DLPFC) and subgenual anterior cingulate cortex was identified (p=0.0004).
• Post-treatment changes in cortical thickness SCN architecture correlated with clinical improvement in responders (p=0.001).

Conclusions:

• Structural network changes, particularly post-treatment alterations in SCN architecture, may underlie clinical response to rTMS in MDD.
• SCNs are valuable tools for understanding depression pathophysiology and the neural mechanisms of plasticity in response to circuit-based treatments like rTMS.