The overall goal of this protocol is to evaluate the binding of caffeine to adenosine A2A receptors in the brain of participants at risk for developing PD. The specific objectives are:~To evaluate the pharmacokinetics (PK) and pharmacodynamics of multiple doses of oral caffeine on striatal binding of the adenosine A2A receptor ligand [18F]MNI-444.~To evaluate the safety and tolerability of 3 doses of the positron emission tomography (PET) radiotracer, [18F]MNI-444.~To evaluate the safety and tolerability of multiple doses of oral caffeine in this paradigm.
The overall goal of this protocol is to evaluate the binding of caffeine to adenosine A2A receptors in the brain of participants at risk for developing PD.