title: Cerebral activation in patients with irritable bowel syndrome and control subjects during rectosigmoid stimulation.
abstract: OBJECTIVE
  Patients with irritable bowel syndrome (IBS) show evidence of altered perceptual responses to visceral stimuli, consistent with altered processing of visceral afferent information by the brain. In the current study, brain responses to anticipated and delivered rectal balloon distension were assessed.
  
  
  METHODS
  Changes in regional cerebral blood flow were measured using H2(15)O-water positron emission tomography in 12 nonconstipated IBS patients and 12 healthy control subjects. Regional cerebral blood flow responses to moderate rectal distension (45 mm Hg) and anticipated but undelivered distension were assessed before and after a series of repetitive noxious (60-mm Hg) sigmoid distensions.
  
  
  RESULTS
  Brain regions activated by actual and simulated distensions were similar in both groups. Compared with control subjects, patients with IBS showed lateralized activation of right prefrontal cortex; reduced activation of perigenual cortex, temporal lobe, and brain stem; but enhanced activation of rostral anterior cingulate and posterior cingulate cortices.
  
  
  CONCLUSIONS
  IBS patients show altered brain responses to rectal stimuli, regardless of whether these stimuli are actually delivered or simply anticipated. These alterations are consistent with reported alterations in autonomic and perceptual responses and may be related to altered central noradrenergic modulation.
authors.affiliation: CURE Digestive Diseases Research Center/Neuroenteric Disease Program, University of California School of Medicine, VA Greater Los Angeles Health Care System, 90073, USA. naliboff@ucla.edu
authors.forename: B D
authors.initials: BD
authors.lastname: Naliboff
authors.forename: S W
authors.initials: SW
authors.lastname: Derbyshire
authors.forename: J
authors.initials: J
authors.lastname: Munakata
authors.forename: S
authors.initials: S
authors.lastname: Berman
authors.forename: M
authors.initials: M
authors.lastname: Mandelkern
authors.forename: L
authors.initials: L
authors.lastname: Chang
authors.forename: E A
authors.initials: EA
authors.lastname: Mayer
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D012809:Colon, Sigmoid / Q000502:physiology*; D003109:Colonic Diseases, Functional / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D004594:Electrophysiology / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009619:Nociceptors / Q000502:physiology; D014055:Tomography, Emission-Computed