In neurodegenerative conditions such as Parkinson's disease (PD), patients often do not receive a diagnosis until the hallmark motor symptoms begin to manifest. This can be a decade or more after substantial changes start occurring in the brain. A major goal of the PD research field has been to develop methods for earlier detection and intervention. Over the years, there have been substantial advances in neuroimaging techniques and biological biomarkers that have allowed us to more accurately identify patients with Parkinson's disease, including the recent development of the alpha-synuclein seed amplification assay. In this episode, Dr. John Seibyl discusses his early work on neuroimaging in Parkinson's disease through to the groundbreaking, large-scale clinical trials he is involved with for assessing the impacts of neuroprotective drugs for Parkinson's disease as well as Alzheimer's disease. He also shares his perspectives as a researcher and a patient with Parkinson's disease. John is Chairman of the Board, Co-Founder, and Senior Scientist of the Institute for Neurodegenerative Disorders in New Haven, Connecticut. He is also a board-certified physician in both Psychiatry and Nuclear Medicine, and he is an Adjunct faculty member in Neurology at Yale University School of Medicine. This podcast is geared toward researchers and clinicians. If you live with Parkinson’s or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson’s Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.