A Heavy Feeling in the Stomach: Neural Correlates of Anxiety in Crohn's Disease

Introduction: Crohn's disease (CD) is a chronic inflammatory condition associated with psychological stress and anxiety. Functional magnetic resonance imaging (fMRI) studies have shown differences in brain function between patients with CD and healthy controls (HC). This study aimed to compare the neural correlates of anxiety inindividuals with CD relative to HC, using resting-state fMRI data. Methods: Participants filled in the State-Trait Anxiety Inventory (STAI), a validated tool for measuring anxiety, and underwent an MRI acquisition, including both structural and functional sequences, to identify brain regions associated with anxiety scores. Results: Seventeen patients with CD and eighteen HC matched for age, education, and sex participated in the study. No significant group differences emerged in the STAI scores. However, resting-state fMRI analysis revealed distinct patterns of functional connectivity associated with anxiety scores for the two study groups. Among CD group, greater STAI scores correlated with increased functional connectivity, whereas, in HC, they correlated with decreased functional connectivity. Significant clusters were found in brain regions belonging to specific resting-state networks (RSNs): (a) Posterior Cingulate Cortex (PCC, within the Default Mode Network), (b) left Middle Frontal Gyrus (within the Left Fronto-Parietal Network), and (c) PCC and right Superior Temporal Gyrus (within the Dorsal Attention Network). Conclusion: The differential association between functional connectivity and STAI scores observed for CD and HC participants was located in areas within self-referential (Default Mode Network) and cognitive (Left Fronto-Parietal Network and Dorsal Attention Network) RSNs. Our findings suggest that maladaptive/dysfunctional processing of negative emotions and visceral sensitivity may occur in patients with CD.