Quantitative Meta-Analysis Identifies Brain Regions Activated during Rectal Distension in Irritable Bowel Syndrome.
Gastroenterology. 2010 Aug 6;
Authors: Tillisch K, Mayer EA, Labus JS
BACKGROUND AND AIMS:: The responsiveness of the central nervous system (CNS) is altered in patients with irritable bowel syndrome (IBS). However, due variations in experimental paradigms, analytic techniques, and reporting practices, little consensus exists on brain responses to visceral stimulation. We aimed to identify brain regions consistently activated by supraliminal rectal stimulation in IBS patients and healthy subjects (controls), by performing a quantitative meta-analysis of published studies. METHODS:: Significant foci from with-in group statistical parametric maps were extracted from published neuroimaging studies that employed rectal distension. Voxel-based activation likelihood estimation was applied, pooling the results and comparing them across groups. RESULTS:: Across studies, there was consistent activation in regions associated with visceral afferent processing (thalamus, insula, anterior mid-cingulate) among IBS patients and controls, but considerable differences in the extent and specific location of foci. IBS patients differed from controls in: 1) More consistent activations in regions associated with emotional arousal [pregenual anterior cingulate cortex (pACC), amygdala]; 2) Activation of a midbrain cluster, a region playing a role in endogenous pain modulation. Controls showed more consistent activation of the medial and lateral prefrontal cortex. CONCLUSIONS:: Patients with IBS have greater engagement of regions associated with emotional arousal and endogenous pain modulation, but similar activation of regions involved in processing of visceral afferent information. Controls have greater engagement of cognitive modulatory regions. These results support a role for CNS dysregulation in IBS. These findings provide specific targets for guiding development of future neuroimaging protocols to more clearly define altered brain-gut interactions in IBS.
PMID: 20696168 [PubMed - as supplied by publisher]
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