Disturbed Interhemispheric Functional Connectivity Rather than Structural Connectivity in Irritable Bowel Syndrome.

Area of Science:

• Neuroimaging
• Gastroenterology
• Neuroscience

Background:

• Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by relapsing symptoms.
• Previous neuroimaging studies suggest disrupted brain connections in IBS patients.
• Alterations in interhemispheric functional and structural connectivity in IBS remain largely unknown.

Purpose of the Study:

• To investigate interhemispheric functional and structural connectivity changes in IBS patients.
• To explore the relationship between altered connectivity and clinical symptoms.

Main Methods:

• Combined resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI).
• Acquired data from 65 IBS patients and 67 healthy controls (HCs).
• Calculated voxel-mirrored homotopic connectivity (VMHC) and analyzed diffusion tensor imaging (DTI) tractography metrics.

Main Results:

• IBS patients exhibited altered VMHC, with increased connectivity in several regions (thalami, cuneus, PCC, lingual gyri, occipital/cerebellum lobes) and decreased connectivity in others (vACC, IPL).
• Anxiety and depression covariates eliminated VMHC differences in the ventral anterior cingulate cortex (vACC).
• No significant differences in white matter microstructural features were found between groups; vACC VMHC negatively correlated with quality of life (QOL).

Conclusions:

• IBS is associated with disrupted interhemispheric functional coordination, not structural deficits, within the cortex-thalamus circuit.
• Altered functional connectivity may contribute to altered visceral information processing and impaired pain/emotion inhibition in IBS.
• The role of anxiety and depression in modulating these connectivity changes warrants further investigation.