Dr. Hoffer, has been involved in Parkinson’s disease research since 1972, when he worked on the first 6 OHDA models in pre-clinical models with Dr. Urban Ungerstedt at National Institute of Mental Health and at the Karolinska Institute.  His work on PD, in collaboration with Dr. Lars Olson and others over the last 40 years, has involved the first pre-clinical model studies of fetal nigral cell grafts (Science 1979), the first human brain cell transplantation work into pre-clinical models (Exp Brain Research, 1987), the first human transplantation trials (Annals of Neurology, 1987), the first in vivo studies of GDNF into pre-clinical models (Neursci Letters, 1994), and most recently, a new mitochondria-based pre-clinical model for PD (Proc Nat Acad Sci, 2007).

As a National Institutes of Health Scientist Emeritus he, together with Dr. Yun Wang, maintains laboratory facilities at National Institute of Drug Abuse for behavioral testing, immunocytochemistry, and biochemical analysis of midbrain DA circuitry in various pre-clinical models of PD.