*Gastroenterology* (vol. 134, #2, February, 2008 )
includes a study: “Effect of Abuse History on Pain Reports and Brain
Responses to Aversive Visceral Stimulation: An fMRI Study.”

The article is by Yehuda Ringel, Douglas A. Drossman, Jane L. Leserman,
Brandall Y. Suyenobu, Kathy Wilber, Weili Lin, William E. Whitehead,
Bruce D. Naliboff, Steven Berman, & Emeran A. Mayer.

Here’s the abstract:

Background & Aims:

Abuse history is common in irritable bowel syndrome (IBS) and is
associated with greater pain reporting, psychologic distress, and poorer
health outcome. These effects may be mediated by enhanced responses to
aversive visceral stimuli. We investigated the effects of IBS and abuse
history on pain reporting and brain activation in response to rectal
distentions.

Methods:

Ten female patients with IBS and 10 controls were included. Half of
patients in each group reported a history of abuse. Brain functional
magnetic resonance imaging (fMRI) images and pain ratings were obtained
during rectal distentions. Statistical parametric mapping identified
activation in subregions of the dorsal cingulate cortex and covariation
with rated pain.

Results:

(1) Distention-elicited pain correlated with anxiety and activation of
the posterior (PCC) and middle (MCC) dorsal cingulate subregions. (2)
Subjects with a history of abuse showed greater activation in the left
MCC (P = .022; t = 5.61) and PCC (P = .033; t = 5.00) than subjects
without abuse. (3) Those with IBS and abuse reported greater pain than
all others (P = .004), had more activity in the left MCC (P = .021; t =
5.29) and PCC (P = .049; t = 4.81), and had less activity in the left
supragenual anterior cingulate (sACC) (P = .01; t = 4.86).

Conclusions:

Pain ratings during rectal distention are associated with activation of
dorsal cingulate regions implicated in homeostatic afferent processing,
and prior abuse enhances this activation. Patients with IBS and abuse
report more pain, greater MCC/PCC activation, and reduced activity of a
region implicated in pain inhibition and arousal (sACC). These findings
suggest a possible explanation for the clinical observation of greater
pain reporting and poorer outcome in IBS patients with a history of abuse.

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