Altered static and dynamic functional connectivity in subthreshold bulimia nervosa: A resting-state functional magnetic resonance imaging(fMRI) study

Abstract Bulimia nervosa (BN) is one of the most serious eating disorders (EDs) associated with long-term significant impairment to both physical and mental quality of life. Subthreshold BN emphasize that individuals reported some extent bulimic symptoms, even those individuals who did not fully meet the diagnostic criteria endure elevated levels of impulsivity and higher likelihood of self-harm. Therefore, the current study aimed to identify potential neurobiological signatures of high-risk individuals with BN symptoms. We used functional magnetic resonance imaging (fMRI) to investigate the differences between a subthreshold BN group (sub-BN, n = 61) and a control group (n = 51) in terms of degree centrality (DC), with the secondary analysis of the connectivity in these ROIs showing differences in both static functional connectivity (sFC) and dynamic functional connectivity (dFC) with age, sex, and framewise displacement (FD) as covariates of no interest (p < 0.05, GRF corrected). The sub-BN group exhibited significantly increased DC in the left middle frontal gyrus (MFG) and the orbital frontal gyrus, increased MFG‒superior occipital gyrus connectivity, MFG‒middle occipital gyrus connectivity and MFG‒triangular part of the inferior frontal gyrus (IFGtriang) connectivity, and decreased variability in MFG‒anterior cingulate cortex connectivity. Furthermore, in the sub-BN group, a positive correlation was observed between self-reported BN symptoms and MFG‒IFGtriang connectivity. These findings implicated in reward value processing, cognitive control, and self-referential processing in individuals with BN symptoms, which provided important insights into understanding the pathology of BN.