Diverse and region-specific dysregulation of BDNF-TrkB signaling has been observed in many neuropsychiatric disorders such as Alzheimer’s disease (AD), Parkinson’s disease, Amyotrophic Lateral Sclerosis (ALS), Huntington’s disease, epilepsy, stroke, mood disorders and schizophrenia. The gene discussed is BDNF; the disease is Parkinson disease.