52nd Robert Graves Lecture was presented on Thursday 24th May 2012 in the Royal College of Physicians of Ireland, 6, Kildare Street, Dublin 2

Topic: Bugs on the brain; brain in the gut - seeking explanations for common gastrointestinal symptoms

Lecturer: Prof Eamonn Quigley, MD Professor of Medicine and Human Physiology, Alimentary Pharmabiotic Centre, University College Cork

Summary: "For decades, if not centuries, such common gastrointestinal complaints as chronic or intermittent pain, bloating, distension, “gas” and altered bowel habit (often codified as irritable bowel syndrome – IBS) were attributed to the emotional frailty or psychological vulnerability of the sufferer who was informed by the all-knowing and condescending physician that these symptoms “are all in your head” and advised to “pull yourself together”. Fortunately, matters have moved a little forward. Firstly, the impact of such symptoms on the individual sufferer and society, for some of these afflicted, are more thoroughly understood and, secondly, the rigors of modern medical science have begun to be applied to IBS. From studies in man, as well as animal models, several concepts have emerged which may not be mutually exclusive and, while none may explain the gamut of presentations and natural histories that comprise a disorder as heterogeneous as IBS, each may be relevant to a given symptom or population subtype. Dysmotility, visceral hypersensitivity, altered brain-gut communication, disturbed visceral representation in the brain and hypothalamic-pituitary-adrenal axis dysfunction are now accepted paradigms to explain IBS pathophysiology; more recent arrivals include such unexpected entrants as low-grade inflammation/immune activation and an altered gut microbiota. This lecture will attempt to critically assess the relative contributions of each of these phenomena to the pathogenesis of IBS and to the precipitation of common gastrointestinal symptoms”