The effect of BDNF on motor function is suggested by the association between the Val66Met SNP and reduced experience‐dependent plasticity of motor cortex (Kleim et al., 2006) as well as impaired synaptic plasticity in the nigrostriatal system (Egan et al., 2003) which could play a role in the development of MLIC in PD patients. This evidence concerns the gene BDNF and Parkinson disease.