Characterization of brain functional connectivity in treatment-resistant depression

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Treatment-resistant depression (TRD) poses a significant clinical challenge.
• Deep brain stimulation (DBS) is an emerging therapeutic option for TRD.
• Understanding the neural circuitry of TRD is crucial for optimizing DBS targets.

Purpose of the Study:

• To characterize functional connectivity (FC) in key brain regions targeted for DBS in TRD patients.
• To investigate the influence of gender and brain lateralization on FC in TRD.
• To evaluate the utility of graph theory metrics in analyzing brain network alterations in TRD.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was used to assess FC.
• Thirty-one TRD patients and twenty-nine healthy controls (HC) were included.
• Graph theory nodal degree was calculated for subcallosal cingulate gyrus, ventral caudate, nucleus accumbens, lateral habenula, and inferior thalamic peduncle.

Main Results:

• TRD patients exhibited significantly greater nodal degree in the left and right ventral caudate, left lateral habenula, and left inferior thalamic peduncle compared to HC.
• Females with TRD showed higher nodal degree in these regions, except the right lateral habenula.
• The left hemisphere was more affected, with significant degrees observed in the lateral habenula and inferior thalamic peduncle.

Conclusions:

• Nodal degree effectively characterizes brain FC and identifies abnormal activity in TRD.
• Graph-theoretical features like degree may aid in understanding TRD mechanisms.
• These findings support the potential of degree measures to assist in selecting appropriate DBS targets for TRD.