BDNF and Parkinson disease: BDNF is of particular therapeutic interest because of its neurotrophic actions on a number of neuronal populations including sensory neurons (implicated in peripheral sensory neuropathies [6]); motor neurons which are degenerated in amyotrophic lateral sclerosis (ALS) [7]; dopaminergic neurons of the substantia nigra, which are lost in Parkinson’s disease (PD); and cholinergic neurons of the basal forebrain, that play a significant role in in Alzheimer’s disease (AD) [8].