Evaluation of [18F]MNI-1126 as an Imaging Marker for Synaptic Density Loss

Inclusion Criteria (for all subjects) * Written informed consent must be obtained before any assessment is performed. * Female subjects must be documented by medical records or physician's note to be either surgically sterile (by means of hysterectomy, bilateral oophorectomy, or tubal ligation) or post-menopausal for at least 1 year (i.e. 12 consecutive months with no menses without an alternative medical cause) or, if they are of child-bearing potential, must commit to use two methods of contraception, one of which is a barrier method for the duration of the study. * Male subjects and their partners of childbearing potential must commit to the use of two methods of contraception, one of which is a barrier method for male subjects for the study duration. * Male subjects must not donate sperm for the study duration. * Willing and able to cooperate with study procedures. * For females, non-child bearing potential or negative urine pregnancy test on day of \[18F\]MNI-1126 injection. Inclusion Criteria PD subjects: * Are males or females ≥ 30 years of age. * Must have at least two of the following: resting tremor, bradykinesia, rigidity (must have either resting tremor or bradykinesia); OR either asymmetric resting tremor or asymmetric bradykinesia. * Have Hoehn and Yahr stage ≤3. * Have a MMSE score ≥ 22. * PD subjects may be treated with PD symptomatic therapy on a stable dose of medications for a period of at least 30 days prior to the \[18F\]MNI-1126 PET imaging visit. * H…