title: Diffusion tensor imaging detects microstructural reorganization in the brain associated with chronic irritable bowel syndrome.
abstract: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by recurring abdominal pain associated with alterations in bowel habits. We hypothesized that patients with chronic visceral pain associated with IBS may have microstructural differences in the brain compared with healthy control subjects (HCs), indicative of long-term neural reorganization of chronic pain pathways and regions associated with sensory integration. In the current study we performed population-based voxel-wise diffusion tensor imaging (DTI) comparisons and probabilistic tractography in a large sample of phenotyped patients with IBS (n=33) and in HCs (n=93). Patients had lower fractional anisotropy (FA) in thalamic regions, the basal ganglia (BG) and sensory/motor association/integration regions as well as higher FA in frontal lobe regions and the corpus callosum. In addition, patients had reduced mean diffusivity (MD) within the globus pallidus (GP) and higher MD in the thalamus, internal capsule, and coronal radiata projecting to sensory/motor regions, suggestive of differential changes in axon/dendritic density in these regions. Sex differences in FA and MD were also observed in the patients but not in HCs. Probabilistic tractography in patients confirmed a higher degree of connectivity between the thalamus and prefrontal cortex, as well as between the medial dorsal thalamic nuclei and anterior cingulate cortex, and a lower degree of connectivity between the GP and thalamus. Together, these results support the hypothesis that patients with chronically recurring visceral pain from IBS have long-term microstructural changes within the brain, particularly in regions associated with integration of sensory information and corticothalamic modulation.
authors.affiliation: Department of Radiological Science, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA Department of Biomedical Physics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA Department of Bioengineering, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA Center for the Neurobiology of Stress, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA Department of Digestive Diseases and Gastroenterology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
authors.forename: Emeran
authors.initials: E
authors.lastname: Mayer
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Harris
authors.forename: Cody
authors.initials: C
authors.lastname: Ashe-McNally
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Naliboff
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Labus
authors.forename: Kirsten
authors.initials: K
authors.lastname: Tillisch
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D002908:Chronic Disease; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D043183:Irritable Bowel Syndrome / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology; D055815:Young Adult
keywords: Chronic Pain; DTI; Diffusion Tensor Imaging; IBS; Irritable Bowel Syndrome; Reorganization