Illustration of the major aspects of the study. Baseline measures (behavioral, PET) precede treatment with intracarotid MPTP. One week after MPTP administration, each animal is assessed to verify nigrostriatal damage, and randomized to either a treatment (C3) or placebo infusion for 8 weeks. Repeated behavioral measures are made during the 8 weeks of infusion. At the end of the infusion interval, terminal PET measures are done, the animal euthanized and in vitro measures (DA, TH) are performed. Note that the process for the treatment and control arms are identical, and that both infusions begin well after (7 days) administration of neurotoxin.