LAUSR

BACKGROUND Growing evidences support that abnormalities in brain-gut-microbiome (BGM) interactions have been implicated in the pathogenesis of irritable bowel syndrome (IBS). Our study aimed to explore the alterations in dynamic functional connectivity (DFC), gut microbiome and the bidirectional interaction in the BGM. METHODS Resting-state functional magnetic resonance imaging (rs-fMRI), fecal samples and clinical measures were collected from 33 IBS patients and 32 healthy controls. We performed a systematical DFC analysis on rs-fMRI. The gut microbiome were analyzed by 16S rRNA gene sequencing. Associations between DFC characteristics and microbial alterations were explored. RESULTS In DFC analysis, four dynamic functional states were identified. IBS patients exhibited increased mean dwell and fraction time in State 4, and reduced transitions from State 3 to State 1. The aberrant temporal properties in State 4 were only evident when choosing a short window (36s or 44s). Decreased functional connectivity (FC) variability was found in State 1 and State 3 of IBS patients, two of which showed significant correlations with clinical characteristics. Additionally, we identified 9 significantly differential abundances in microbial composition. We also found that IBS-related microbiota was associated with aberrant FC variability, albeit these exploratory results obtained at an uncorrected threshold of significance. CONCLUSIONS Although future studies are needed to confirm these findings, our findings not only provide a new insight for the dysconnectivity hypothesis in IBS from a dynamic perspective, but also established a possible link between the DFC and gut microbiome, which laid the foundation for future research on the disrupted BGM interactions.