Structural brain network analysis in families multiply affected with bipolar I disorder

Area of Science:

• Neuroscience
• Psychiatry
• Network Science

Background:

• Structural brain connectivity disruptions are linked to psychiatric disorders like bipolar disorder (BP).
• Investigating these disruptions may reveal biomarkers and endophenotypes for BP.
• Previous studies suggest frontal lobe involvement in BP.

Purpose of the Study:

• To examine structural brain network abnormalities in families with multiple BP type I cases.
• To evaluate the potential of brain dysconnectivity as a biomarker and endophenotype for BP.
• To compare brain network organization between BP I patients, their unaffected relatives, and healthy controls.

Main Methods:

• Utilized magnetic resonance diffusion imaging and tractography on 19 BP I patients, 21 unaffected relatives, and 18 healthy controls.
• Generated brain connectivity matrices using the Automated Anatomical Labeling atlas.
• Analyzed network metrics with the Brain Connectivity Toolbox, controlling for age, gender, and familial factors.

Main Results:

• Whole-brain network analysis showed no significant differences between the groups.
• However, analysis of specific frontal regions revealed reduced organizational efficiency in BP I patients compared to controls.
• These frontal region differences were not observed in unaffected relatives.

Conclusions:

• Whole-brain structural network organization does not differ between BP I patients, their relatives, and controls.
• Specific frontal regions exhibit disrupted anatomical connectivity in BP I patients.
• These localized frontal deficits may represent an endophenotype for bipolar I disorder.