BDNF and Parkinson disease: More specifically, since the late 1990s, different post-mortem studies demonstrated the reduction of BDNF protein in SNpc and striatal nuclei (caudate and putamen) of patients with PD (Mogi et al., 1999; Parain et al., 1999), as more recently confirmed by the results in the work of Nagatsu and Sawada (2007).