The purpose of this research study is to improve the understanding of irritable bowel syndrome (IBS) and its underlying cause. The investigators will use magnetic resonance imaging (MRI) to observe differences in the brain between people diagnosed with IBS compared to healthy controls and people with ulcerative colitis, a disease group that has already been characterized. By doing this correlative and comparative study, the investigators hope to gain knowledge on IBS in order to keep the field moving in the right direction and becoming one step closer to discovering effective treatments.