Surface-based regional homogeneity in bipolar disorder: A resting-state fMRI study

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Bipolar disorder (BD) is a mood disorder characterized by abnormal neuronal activity.
• Previous studies often used volume-based 3D regional homogeneity (3dReHo), but surface-based 2D regional homogeneity (2dReHo) offers a novel approach.

Purpose of the Study:

• To compare local functional synchronization of spontaneous neuronal activity between BD patients and healthy controls (HC) using surface-based 2dReHo.
• To investigate the relationship between 2dReHo, age, and BD pathophysiology.

Main Methods:

• Resting-state functional MRI (fMRI) scans were acquired from 71 BD patients and 113 HC.
• Surface-based 2dReHo analysis was applied to resting-state fMRI data.
• Participants were assessed using the Young Mania Rating Scale and Hamilton Depression Rating Scale.

Main Results:

• BD patients demonstrated reduced global 2dReHo across the cortical surface compared to HC.
• Specifically, reduced 2dReHo was observed in the left ventral visual stream (VVS) of BD patients.
• A significant negative correlation between global 2dReHo and age was found in both BD patients and HC.

Conclusions:

• Surface-based 2dReHo reveals widespread reductions in functional synchronization in bipolar disorder.
• Abnormal activity in the left VVS cortex may be implicated in the pathogenesis of BD.
• Surface-based 2dReHo is a promising tool for investigating the pathophysiology of BD.