title: Novel evidence for hypersensitivity of visceral sensory neural circuitry in irritable bowel syndrome patients.
abstract: OBJECTIVE
  Visceral hypersensitivity in irritable bowel syndrome (IBS) patients has been documented by evaluation of perceived stimulations that can reflect abnormalities of both sensory neurocircuitry and cognitive processes. The presence of actual neurohypersensitivity in human beings has not been documented separately. Because subliminal stimulations are free from the influence of stimulus-related cognitive processes, functional magnetic resonance imaging (fMRI) cortical response to these stimuli can be considered a measure of activity of the neural circuitry alone. The aim of this study was to compare quantitatively the cerebral cortical fMRI activity response to equal subliminal stimulations between IBS patients and age-matched controls.
  
  
  METHODS
  We studied 10 IBS patients and 10 healthy controls using a computerized barostat-controlled rectal distention device. fMRI activity volume and percent maximum signal intensity change for equal subliminal distention pressures were compared between controls and patients.
  
  
  RESULTS
  Three levels of subliminal distention pressures (eg, 10, 15, and 20 mm Hg), were represented in both controls and patients and were analyzed for fMRI response. In all 3 distention levels the fMRI activity volume in IBS patients was significantly larger than age- and sex-matched controls (P < .05). The percent maximum signal intensity change was similar between IBS patients and controls.
  
  
  CONCLUSIONS
  The volume of cerebral cortical activity response to equal subliminal distention pressures in IBS patients is significantly larger than in controls, documenting the existence of hypersensitivity of the neural circuitry in this patient group irrespective of stimulus-related cognitive processes.
authors.affiliation: Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Adeyemi
authors.initials: A
authors.lastname: Lawal
authors.forename: Mark
authors.initials: M
authors.lastname: Kern
authors.forename: Harjot
authors.initials: H
authors.lastname: Sidhu
authors.forename: Candy
authors.initials: C
authors.lastname: Hofmann
authors.forename: Reza
authors.initials: R
authors.lastname: Shaker
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D011312:Pressure; D012007:Rectum / Q000294:innervation*