Aberrant interhemispheric functional connectivity in major depressive disorder with and without anhedonia

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Anhedonia is a primary symptom of major depressive disorder (MDD).
• The specific neuropathology of anhedonia within MDD remains poorly understood.
• Investigating brain functional differences in MDD subtypes is crucial for understanding disease mechanisms.

Purpose of the Study:

• To investigate functional brain differences between MDD patients with and without anhedonia.
• To identify distinct neurobiological mechanisms underlying anhedonia in MDD.
• To compare brain connectivity patterns in MDD subtypes and healthy controls.

Main Methods:

• Recruited 62 participants: 22 MDD with anhedonia, 20 MDD without anhedonia, and 20 healthy controls (HCs).
• Utilized 3.0-T functional magnetic resonance imaging (fMRI) scans.
• Applied voxel-mirrored homotopic connectivity (VMHC) analysis to assess interhemispheric functional connectivity.

Main Results:

• Significant VMHC differences were found among the three groups in the bilateral middle temporal gyrus (MTG), superior frontal gyrus (SFG), and inferior parietal lobule (IPL).
• MDD with anhedonia exhibited decreased VMHC in the bilateral MTG and increased VMHC in the bilateral SFG compared to HCs.
• MDD with anhedonia showed decreased VMHC in the bilateral MTG and IPL, and increased VMHC in the bilateral SFG compared to MDD without anhedonia.

Conclusions:

• MDD with and without anhedonia display unique patterns of interhemispheric brain connectivity.
• Anhedonia in MDD is associated with disrupted connectivity within the frontal-temporal-parietal neural circuit.
• These findings contribute to understanding the neurobiological underpinnings of anhedonia in depression.