Central processing of rectal pain: A functional MR imaging study

BACKGROUND AND PURPOSE: Although the central processing of somatic pain has been dealt with in numerous brain imaging studies, the neural correlates o f visceral pain have received much more limited attention. Our goal was to assess the feasibility of detecting brain activation patterns induced by re ctal pain by means of functional MR imaging, We hypothesized that the cereb ral processing of rectal pain would exhibit strong similarities with the ce ntral processing of somatic pain. METHODS: Functional MR imaging data were obtained from eight healthy subjec ts. A block paradigm was applied, Rectal pain was induced by inflating a la tex balloon catheter that had been inserted into the rectum, Functional res ponses were established by means of cross-correlation analysis, RESULTS: Activation was detected within the anterior cingulate gyrus, the p refrontal cortex, the insular cortex, the sensory-motor cortex, the inferio r parietal lobule, the posterior cingulate gyrus, and the visual cortex. CONCLUSION: Functional MR imaging of visceral pain is feasible in healthy s ubjects. The activation patterns observed in this study support the hypothe sis that the cerebral processing of visceral pain involves multiple compone nts, similar to the central processing of somatic pain, Our results constit ute a first step toward the identification of possible aberrations in the a ctivation patterns of patients suffering from visceral hypersensitivity.