Altered Brain Responses Seen in Irritable Bowel Syndrome
Lack of inhibition of certain brain circuits may contribute to increased perception of visceral pain
THURSDAY, Jan. 10 (HealthDay News) -- Patients with irritable bowel syndrome experience more anxiety and fail to downregulate activity in certain brain areas in anticipation of an uncomfortable visceral stimulus compared to controls, according to an article published in the Jan. 9 issue of the Journal of Neuroscience.
Steven M. Berman, Ph.D., of the University of California Los Angeles, and colleagues performed functional MRI scanning of the brains of 14 female irritable bowel syndrome patients and 12 healthy female controls as they anticipated mild to moderate rectal distention achieved by balloon inflation.
During anticipation of pelvic/abdominal discomfort, brain activity decreased in the insula, supragenual anterior cingulate cortex (ACC), amygdala and dorsal brainstem (DBS) of controls, but irritable bowel syndrome patients showed less anticipatory inactivation in these regions. In addition, irritable bowel syndrome patients reported more negative emotions during the scanning, which correlated inversely with the degree of DBS inactivation. During rectal distention, both groups showed increases in activity in the insula, dorsal ACC and DBS, with irritable bowel syndrome patients showing the greatest increases.
"The current results demonstrate that during certain expectation of experimental abdominal/pelvic discomfort, female irritable bowel syndrome-constipation patients are more anxious and less able than healthy controls to downregulate activity within the central nervous system network activated by potentially aversive interoceptive stimuli, especially within the DBS," the authors conclude.