MesencephalonTrigeminal NucleiBrain Tissue TransplantationFetal Tissue TransplantationDopamineReticular FormationTyrosine 3-MonooxygenaseNeurons1-Methyl-4-phenylpyridiniumSubstantia NigraDiencephalonDopaminergic NeuronsNuclear Receptor Subfamily 4, Group A, Member 2MetencephalonOxidopamineTrigeminal NerveSpirostansPonsOculomotor NerveParkinson Disease