Objective: The application of functional imaging to study visceral sensation has generated considerable interest regarding insight into the function of the brain-gut axis, but also some contradictory and confusing results that require appraisal.
Methods: Published studies of visceral sensation were grouped according to stimulus region and study population. The results of each study were tabulated and the center of reported activations plotted onto the lateral and medial surface of a representative brain.
Results: Esophageal distension predominantly activated primary sensory and motor cortices and the midsection of the medial surface. Lower GI distension predominantly activated bilateral prefrontal and orbitofrontal cortices and more anterior and ventral regions of the medial surface.
Conclusions: Activation sites are reasonably well clustered within stimulus modality, implying consistent brain response to visceral sensation. The differences in reported activation during esophageal and lower GI sensation imply altered motor, autonomic, and affect response during distension at opposite ends of the GI tract that may be explored in future studies.