Supranigral infusions of BDNF and NT-3 alter circadian rhythms, spontaneous motor activity, body weights, and amphetamine-induced behaviors including locomotion and contraversive rotations. Our findings show that neurotrophins are able to promote the survival of striatal projection neurons in vivo and suggest that BDNF might be beneficial for the treatment of striatonigral degenerative disorders, including Huntington's disease.