Disclosed and claimed are methods for treating or preventing neurodegenerative diseases, conditions or maladies or symptoms or physiology associated therewith, such as treating or preventing Parkinson's disease or symptoms or physiology associated therewith such as motor deficits or nigrostriatal degeneration; or, for inducing nigrostriatal regeneration. Advantageously, the methods involve administering a lentiviral vector that expresses GDNF, such as human GDNF, or a variant, homolog, analog or derivative thereof.