Inclusion Criteria:  Inclusion criteria for PD patients: age 50-80 years old; Junior high school or above, able to read and sign informed consent; Primary PD has just been diagnosed, Hoehn Yahr grade 1-2.5, and has not received any drug or non drug treatment.  The inclusion criteria of healthy control group: age 50-80 years old; Junior high school or above, able to read and sign informed consent.  Exclusion Criteria:  The exclusion criteria of PD patients group were confirmed as secondary PD; Mental retardation, dementia or depression; Other neuropsychiatric diseases (such as epilepsy, schizophrenia), cerebrovascular diseases (such as stroke) or brain trauma; Antidepressants were used; History of alcohol dependence or drug abuse; Head MRI examination (such as claustrophobia, implantable medical device) is not allowed.  Exclusion criteria of healthy control group: Parkinson's disease symptoms (such as static tremor, bradykinesia, limb stiffness); Mental retardation, dementia or depression; REM sleep behavior disorder; There were symptoms of hypoosmia; Other neuropsychiatric diseases, cerebrovascular diseases or brain trauma; Antidepressants were used; History of alcohol dependence or drug abuse; No head MRI.