Justin Long, MD, PhD, is Assistant Professor of Neurology in the Section of Aging and Dementia and Knight Alzheimer Disease Research Center at Washington University in St Louis School of Medicine. He completed his MD/PhD training within the Medical Scientist Training Program at Indiana University in 2014. He completed residency training in adult neurology in 2018 and a combined clinical and research fellowship in Aging and Dementia at Washington University in 2020 under the mentorship of Drs. David Holtzman and John Morris before joining the faculty. He leads a research laboratory that studies the molecular and cellular pathogenesis of Alzheimer disease using mouse models of Alzheimer-like pathology. He is affiliated with an NIH-designated Alzheimer Disease Research Center where he leads clinical studies focused on validating biomarkers of Alzheimer disease and studying the natural course of healthy aging and dementia. He serves as Washington University site principal investigator for the national multi-site Alzheimer Disease Neuroimaging Initiative study and has participated in clinical trials of amyloid-targeted therapies in Alzheimer disease. He has an active clinical practice where he evaluates and treats patients with cognitive disorders, including Alzheimer disease, frontotemporal dementia, Lewy body dementia and vascular cognitive impairment.