Brain Resting-State Network Alterations Associated With Crohn's Disease

Abstract

Inflammatory bowel disease (IBD) is a chronic disease that is associated with aspects of brain anatomy and activity. In this preliminary MRI study, we investigated differences in brain structure and in functional connectivity (FC) of brain regions in 35 participants with Crohn's disease (CD) and 21 healthy controls (HC). Voxel-based morphometry (VBM) analysis was performed to contrast CD and HC structural images. Region of interest (ROI) analyses were run to assess FC for resting-state network nodes. Independent component analysis (ICA) identified whole brain differences in FC associated with resting-state networks. Though no structural differences were found, ROI analyses showed increased FC between the frontoparietal (FP) network and salience network (SN), and decreased FC between nodes of the default mode network (DMN). ICA results revealed changes involving cerebellar (CER), visual (VIS), and SN components. Differences in FC associated with sex were observed for both ROI analysis and ICA. Taken together, these changes are consistent with an influence of CD on the brain and serve to direct future research hypotheses.

Keywords: Crohn's disease (CD); functional connectivity (FC); functional magnetic resonance imaging (fMRI); inflammatory bowel disease (IBD); resting-state networks (RSNs).

Figure 1

(A) Graphic of ROI-to-ROI contrast showing nodes with increased FC (red) and decreased FC (blue) for the CD group as compared to HCs. (B) Graphic of ROI-to-ROI contrast showing nodes with increased FC (red), decreased FC (blue), and both increased and decreased FC (yellow) for the CD females as compared to the HC females. Both graphics are displayed in axial orientation with the anterior aspect toward the top and right on the right, with ROI-to-ROI connection threshold set by intensity at FDR p < 0.05, two-sided (MPFC, medial pre-frontal cortex; LPFC, lateral pre-frontal cortex; SMG, supramarginal gyrus; LP, lateral parietal; AI, anterior insula; PPC, posterior parietal cortex; STG, superior temporal gyrus).

Figure 2

ICA contrast between CD > HC for (A) the cerebellar network FC with left superior lateral occipital, (B) the visual network FC with left putamen and (C) the right occipital pole, and (D) the salience network FC with the left planum temporale. The female CD > HC contrast revealed altered FC in the (E) DMN with the right temporal pole and (F) left insula, (G) the SMN with left orbitofrontal cortex, and (H) the visual network with the fusiform gyrus, whereas the male CD > HC contrast showed altered FC of (I) the DMN with the right angular gyrus. All slices correspond to the peak activation coordinates with the color bar representing positive t-values in orange and negative t-values in blue. Slices are shown in neurological orientation (left hemisphere on the left of each slice, anterior toward the top of each slice) and are displayed at T threshold = 3.5, uncorrected height threshold p < 0.001, and FDR-corrected cluster threshold p < 0.05.