Altered interhemispheric functional connectivity in remitted bipolar disorder: A Resting State fMRI Study

Area of Science:

• Neuroscience
• Psychiatry
• Brain Imaging

Background:

• Bipolar disorder (BD) is associated with widespread brain connectivity abnormalities.
• Understanding functional connectivity in remitted bipolar disorder (RBD) is crucial for identifying persistent neurobiological markers.
• Interhemispheric functional connectivity in RBD remains poorly understood.

Purpose of the Study:

• To investigate interhemispheric functional connectivity patterns in the whole brain of patients with remitted bipolar disorder (RBD) during resting state.
• To identify specific brain regions with altered functional connectivity in RBD compared to healthy controls (HC).

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was employed.
• Twenty patients with RBD and 38 healthy controls (HC) participated.
• Voxel-mirrored homotopic connectivity (VMHC) was used to measure interhemispheric functional connectivity.

Main Results:

• Patients with RBD demonstrated significantly lower VMHC compared to HC in the middle frontal gyrus and precentral gyrus.
• No regions exhibited increased VMHC in the RBD group.
• No significant correlations were found between VMHC values and clinical variables.

Conclusions:

• Remitted bipolar disorder (RBD) is characterized by impaired interhemispheric coordination.
• Reduced VMHC in specific frontal regions may represent a trait neurobiological feature of bipolar disorder, persisting beyond the acute state.
• These findings contribute to understanding the enduring neural underpinnings of BD.