BDNF and Parkinson disease: Consistently, a decrease in BDNF levels has been reported in neurodegenerative disorders, such as AD [69,71], Huntington’s disease (HD) [72], and epilepsy [73], and recent strategies aimed at sustaining or even amplifying the production of BDNF have been proved to be beneficial in patients with HD [74], AD [75,76], Parkinson’s disease (PD) [77,78], amyotrophic lateral sclerosis (ALS) [79,80,81], stroke [82,83,84], and spinal cord injury [85,86,87,88].