Stephen Gomperts, MD, PhD, is founding director of the Lewy Body Dementia Unit at the Massachusetts General Hospital (MGH) and associate professor of neurology at MGH and Harvard Medical School. His translational and clinical research program works to advance understanding, improve diagnosis and develop novel therapeutic strategies for Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and Alzheimer’s disease. Using PET and MR imaging, he has identified contributions of amyloid, tau, dopamine cell loss and regional atrophy to cognition and disease course in PD and DLB, and he is using novel radiotracers to dissect the molecular contributions to disease. He has also clarified how neurons affected in these disorders engage with the hippocampus, a brain region involved in learning and memory. Building on the reduced risk of PD among smokers, he has found molecular pathways activated by low levels of carbon monoxide that limit pathology in PD models.