Aberrant Brain Structural-Functional Connectivity Coupling in Euthymic Bipolar Disorder

Abstract

Aberrant structural (diffusion tensor imaging, DTI) and resting-state functional (rsfMRI) connectivity are core features of bipolar disorder (BD). However, few studies have explored the integrity agreement between structural and functional connectivity in BD (SC-FC coupling). Such SC-FC coupling index could potentially provide additional clinical predictive value for BD spectrum disorders besides the intra-modality network measures. Thus, we examined the structural (DTI) and resting-state functional network properties, as well as their coupling index, among 57 euthymic BD patients (age 13-28 years, 18 females) and 42 age- and gender-matched healthy controls (age 13-28 years, 16 females). We found that compared to controls, BD patients showed increased structural rich club connectivity as well as decreased functional modularity. Importantly, the coupling strength between structural and functional connectome was decreased in BD patients compared to controls, which emerged as the most powerful feature discriminating the two groups. Our findings suggest that structural-functional coupling strength could serve as a valuable biological trait marker for bipolar disorder over and above the intra-modality network measures. Such measure can have important clinical implications for early identification of BD individuals, and inform strategies for prevention of BD onset and relapse. Funding: This study was funded by the National Natural Science Foundation of China (NSFC: 81471375,81671347), Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders (201805010009), and Guangzhou Municipal Psychiatric Disease Clinical Transformation Laboratory (201805010009), which had no further role in study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the paper for publication. Declaration of Interest: We declare no competing interests. Ethical Approval: This study was approved by the Institutional Review Board of the Guangzhou Brain Hospital.