Lorene Nelson, Ph.D., is Associate Professor and Chief of the Epidemiology Division, Department of Health Research and Policy, at Stanford University School of Medicine. Dr. Nelson's research focus is epidemiologic and genetic research on neurological disorders, with an emphasis on neurodegenerative diseases including Parkinson's disease, amyotrophic lateral sclerosis (ALS) and multiple sclerosis. The primary objectives of Dr. Nelson's research are to identify susceptibility genes for neurodegenerative diseases, to examine disease associations with environmental exposures and protective factors, and to investigate gene-environment interactions. Dr. Nelson is a scientific advisor to the National Multiple Sclerosis Society and the Amyotrophic Lateral Sclerosis Association, and an associate editor of the journals American Journal of Epidemiology and Neuroepidemiology. Dr. Nelson is the editor of the text Neuroepidemiology: From Principles to Practice (New York: Oxford University Press, 2004).