Furthermore, intranasal infusion of GM1 significantlyenhanced expression of tyrosine hydroxylase (TH) in the substantia nigra pars compacta ofthe PD mouse, following the restorations of the expression and nuclear localization of,Nurr1 (also known as NR4A2), a dopaminergic neuron-associated transcription factor. Here, TH is linked to Parkinson disease.