Investigating brain community structure abnormalities in bipolar disorder using path length associated community estimation

• Published in: Human brain mapping Vol. 35; no. 5; pp. 2253 - 2264
• Main Authors: GadElkarim, Johnson J., Ajilore, Olusola, Schonfeld, Dan, Zhan, Liang, Thompson, Paul M., Feusner, Jamie D., Kumar, Anand, Altshuler, Lori L., Leow, Alex D.
• Format: Journal Article
• Language: English
• Published: New York, NY Blackwell Publishing Ltd 01.05.2014; Wiley-Liss; John Wiley & Sons, Inc; John Wiley and Sons Inc
• Subjects: Adult; Biological and medical sciences; bipolar disorder; Bipolar Disorder - complications; Bipolar Disorder - pathology; Brain - pathology; Brain Mapping; community structure; connectome; Female; Functional Laterality; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; hierarchical trees; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Models, Neurological; Nerve Net - physiology; Nervous system; Nervous system (semeiology, syndromes); Neural Pathways - pathology; Neurology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Mood disorder; Nervous system diseases; hierarchical trees; Radiodiagnosis; community structure; Estimation; Central nervous system; Bipolar disorder; connectome; Encephalon; bipolar disorder
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.22324

In this article, we present path length associated community estimation (PLACE), a comprehensive framework for studying node‐level community structure. Instead of the well‐known Q modularity metric, PLACE utilizes a novel metric, ΨPL, which measures the difference between intercommunity versus intracommunity path lengths. We compared community structures in human healthy brain networks generated using these two metrics and argued that ΨPL may have theoretical advantages. PLACE consists of the following: (1) extracting community structure using top‐down hierarchical binary trees, where a branch at each bifurcation denotes a collection of nodes that form a community at that level, (2) constructing and assessing mean group community structure, and (3) detecting node‐level changes in community between groups. We applied PLACE and investigated the structural brain networks obtained from a sample of 25 euthymic bipolar I subjects versus 25 gender‐ and age‐matched healthy controls. Results showed community structural differences in posterior default mode network regions, with the bipolar group exhibiting left‐right decoupling. Hum Brain Mapp 35:2253–2264, 2014. © 2013 Wiley Periodicals, Inc.