Functional connectivity alterations of the somatomotor network in euthymic bipolar disorder

Area of Science:

• Neuroscience
• Psychiatry
• Brain Imaging

Background:

• Bipolar disorder is often characterized by mood episodes, but residual symptoms and impairments persist in euthymic states.
• These enduring deficits may stem from underlying abnormalities in brain functional networks.
• Understanding these network alterations is crucial for improving long-term outcomes in bipolar disorder.

Purpose of the Study:

• To investigate brain network functional connectivity in euthymic individuals with bipolar disorder compared to healthy controls.
• To explore the relationship between functional connectivity, lingering psychomotor symptoms, and illness severity in bipolar disorder.
• To identify potential neural targets for therapeutic interventions in bipolar disorder.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was employed.
• Network-based statistic was used to compare functional connectivity within and between resting-state networks.
• Participants included euthymic individuals with bipolar disorder (N=96) and healthy controls (N=61).

Main Results:

• Individuals with bipolar disorder exhibited stronger functional connectivity between the somatomotor and frontoparietal networks compared to controls.
• Weaker functional connectivity was observed within the somatomotor network and between the somatomotor and visual networks in the bipolar disorder group.
• These findings persisted after controlling for antipsychotic medication use.

Conclusions:

• Altered functional connectivity, particularly between the somatomotor and frontoparietal networks, may underlie persistent symptoms in euthymic bipolar disorder.
• Dysconnectivity within the somatomotor network could be linked to psychomotor symptoms independent of medication effects.
• These results highlight somatomotor network aberrations as a potential avenue for novel brain stimulation treatments in bipolar disorder.