While the loss of dopaminergic neurons in the nigro-striatal pathway is the main neuropathological feature and cause of motor disabilities in PD [3], dopamine (DA) is not generally considered to play a significant role in sleep or circadian rhythms and other neurotransmitters such as noradrenaline, serotonin and orexin have been proposed [4]. Here, HCRT is linked to Parkinson disease.