Patients with irritable bowel syndrome have altered emotional modulation of neural responses to visceral stimuli.Gastroenterology. 2010 Oct; 139(4):1310-9.G
BACKGROUND & AIMS
In patients with irritable bowel syndrome (IBS), pain amplification and hypervigilance might result from altered affective-motivational modulation of the pain response. We investigated the effects of emotional context on the behavioral and neural response to visceral stimuli in IBS patients.
We used functional magnetic resonance imaging (fMRI) to assess the blood oxygen level-dependent response to nonpainful and painful rectal distensions in 15 female IBS patients and 12 healthy women. Distensions were delivered during psychologic stress or relaxation; data were compared with those in a neutral condition (control). Group and context-dependent differences in the processing of visceral stimulation were assessed at behavioral and the neuronal levels. Secondary analyses of group differences were performed using anxiety scores as a covariate because of higher anxiety symptoms among patients with IBS.
During rectal stimulation, IBS patients demonstrated more pronounced stress-induced modulation of neural activation in multiple brain regions, including the insula, midcingulate cortex, and ventrolateral prefrontal cortex. In response to relaxation, IBS patients demonstrated reduced modulation of distension-induced activation in the insula. During relaxation, the difference observed between groups could be accounted for by higher anxiety symptoms in patients with IBS; differential effects of stress in the insula and prefrontal regions were not attributable to anxiety.
IBS patients appear to have disrupted emotional modulation of neural responses to visceral stimuli, possibly reflecting the neural basis for altered visceral interoception by stress and negative emotions.