• Michiko Kano, Tomohiko Muratsubaki, Joe Morishita, Keiji Kono, Shunji Mugikura, Kei Takase, Huynh Giao Ly, Patrick Dupont, Lukas Van Oudenhove, and Shin Fukudo.
• From the Frontier Research Institute for Interdisciplinary Sciences (Kano) and Behavioral Medicine (Kano, Muratsubaki, Morishita, Kono, Fukudo), Graduate School of Medicine, Tohoku University; Diagnostic Radiology (Mugikura, Takase), Tohoku University Hospital, Sendai, Japan; Laboratory for Brain-Gut Axis Studies (Ly, Van Oudenhove), Translational Research Center for Gastrointestinal Disorders, University of Leuven; and Laboratory for Cognitive Neurology (Dupont), KU Leuven, Belgium.
• Psychosom Med. 2017 Nov 1; 79 (9): 988-999.

ObjectiveWe investigated whether certainty and uncertainty of impending aversive visceral sensation differently modulate regional brain activity, both during anticipation and visceral sensation in irritable bowel syndrome (IBS) patients compared with healthy controls.MethodsTwenty-six IBS patients (14 women) and 29 healthy controls (15 women) were enrolled in a functional magnetic resonance imaging study. Participants received rectal distention at an individually titrated severe discomfort level that was preceded by visual cues to induce certain (100% chance of distention), uncertain (50% chance), and safe (0% chance) anticipation.ResultsSubjective ratings of anticipatory fear before and discomfort during distention were similar between IBS and control participants under cued certainty and uncertainty (p > .05). Uncertain anticipation compared with certain anticipation induced greater activation of anterior midcingulate cortex, thalamus, and visual processing areas in IBS patients compared with controls. Rectal distention after the uncertain, but not certain, cue induced higher activity in the posterior- and midcingulate cortices and the precuneus in IBS compared with controls. Controls exhibited bilateral insula activation during the nondistention period after the uncertain cue compared with the safe cue. IBS patients failed to produce this response, which was possibly due to elevated bilateral insular responses during nondistention after the safe cue. Brain data were significant at a voxel-level threshold of puncorrected value of less than .005 combined with a cluster-level threshold of pFWE-corrected value of less than .05.ConclusionsPreceding uncertainty differentially modulates the brain processing of physiologically identical rectal stimulation in IBS patients. Cue-dependent alterations in brain responses may underlie hypervigilance to visceral sensations in IBS patients.

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