title: Behavioural and neural correlates of visceral pain sensitivity in healthy men and women: does sex matter?
abstract: BACKGROUND
  We assessed sex differences in behavioural and neural responses to rectal pain stimuli in healthy subjects.
  
  
  METHODS
  In age- and body mass index-matched healthy subjects (n = 15 men, 15 women), rectal sensory and pain thresholds were assessed with a pressure-controlled barostat device. The blood oxygen level-dependent response during cued anticipation and painful stimulation was measured using functional magnetic resonance imaging (fMRI). Retrospective pain evaluations were accomplished with visual analogue scales. For fMRI data, region-of-interest (ROI) analyses and additional whole-brain analyses were carried out.
  
  
  RESULTS
  There were no sex differences in rectal thresholds or pain ratings. ROI analyses revealed comparable distension-induced activation of the thalamus, somatosensory cortex, insula and dorsolateral prefrontal cortex (DLPFC). Only in additional whole-brain analyses did we find increased activation in women in DLPFC and middle temporal gyrus during pain anticipation and in the cerebellum and medial frontal gyrus during pain. A significant inverse association between rectal pain threshold and distension-induced activation in virtually all ROIs was found in women. In men, pain thresholds and insula activation were positively correlated, as were pain ratings and anterior cingulate cortex activation.
  
  
  CONCLUSIONS
  Healthy men and women do not differ in behavioural measures of visceral pain sensitivity. The pattern of neural activation is comparable in the majority of pain-processing brain regions, although women may differ in the activation of DLPFC which could reflect sex differences in cognitive-emotional pain regulation. Women with lower pain thresholds showed greater neural responses, which may be relevant in the pathophysiology of visceral hyperalgesia.
authors.affiliation: Institute of Medical Psychology & Behavioral Immunobiology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Benson
authors.forename: V
authors.initials: V
authors.lastname: Kotsis
authors.forename: C
authors.initials: C
authors.lastname: Rosenberger
authors.forename: U
authors.initials: U
authors.lastname: Bingel
authors.forename: M
authors.initials: M
authors.lastname: Forsting
authors.forename: M
authors.initials: M
authors.lastname: Schedlowski
authors.forename: E R
authors.initials: ER
authors.lastname: Gizewski
authors.forename: S
authors.initials: S
authors.lastname: Elsenbruch
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D004644:Emotions / Q000502:physiology; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010147:Pain Measurement / Q000379:methods; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D012007:Rectum / Q000503:physiopathology; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D059265:Visceral Pain / Q000503:physiopathology*