Following brain scan changes before and early in Parkinson’s

Inclusion Criteria: * A prodromal PD and Healthy participant enrolled in PPMI Clinical protocol * A PD participant enrolled in PPMI Clinical protocol who has not started symptomatic treatment at time of enrollment or in the first 2 years of participation. * Able to provide informed consent * Must have screening genetic testing documenting high binder at the at the known TSPO gene polymorphism (rs6971) * Male or Female (Females must meet additional criteria specified below, as applicable) • Females must be of non-childbearing potential or using a highly effective method of birth control 14 days prior to until at least 24 hours after injection of \[18F\]DPA-714 * Non-childbearing potential is defined as a female that must be either postmenopausal (no menses for at least 12 months prior to PET scan) or surgically sterile (bilateral tubal ligation, bilateral oophorectomy or hysterectomy). * Highly effective method of birth control is defined as practicing at least one of the following: A birth control method that results in a less than 1% per year failure rate when used consistently and correctly, such as oral contraceptives for at least 3 months prior to injection, an intrauterine device (IUD) for at least 2 months prior to injection, or barrier methods, e.g., diaphragm or combination condom and spermicide. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation methods) is not acceptable. * Females of childbearing potential must not be pregnant, breastfeeding or lactating. * Includes a negative urine pregnancy test prior to injection of \[18F\]DPA-714 on day of PET scan. Exclusion Criteria: * Exposure to a total effective dose equivalent of 50 millisievert (mSv) for the whole body, which is the annual limit established by the US Code of Federal Regulations , during the past year. * Any other medical or psychiatric condition or lab abnormality, which in the opinion of the Site Investigator might preclude participation.