CORTICAL THINNING IN IBS: IMPLICATIONS FOR HOMEOSTATIC, ATTENTION, AND PAIN PROCESSING

Abstract

Chronic pain may be accompanied by abnormal functioning in pain, attention, or homeostatic systems. We recently identified abnormal rectal-evoked functional MRI responses in patients with irritable bowel syndrome (IBS) in brain regions associated with such systems, including the insula and anterior cingulate cortex (ACC).1 However, it is not known whether structural brain abnormalities contribute to these responses. We tested the hypothesis that abnormal cortical responses in IBS are at least partly due to structural differences within the insula and ACC. ### Methods. Right-handed healthy control subjects (n = 11, 7 women, 4 men; 24 to 50 years old) and patients with IBS (n = 9, 6 women, 3 men; 30 to 58 years old) provided written consent to procedures approved by the University Health Network Research Ethics Board. Control subjects were excluded if they had a history of bowel disorders, chronic pain, fibromyalgia, diabetes, or psychiatric illness. Patients were recruited from the Toronto Western Hospital Gastrointestinal Unit, met Rome III criteria2 for diagnosis of IBS, and had mild to moderate symptoms and pain for more than 2 years. Exclusion criteria were a history of …