Serotonin and Amyloidopathy
Serotonin and Amyloidopathy
The purpose of this study is to determine if changes in brain serotonin affects the
 accumulation of amyloid in the brain. The investigators will use brain imaging methods to
 measure the amount of serotonin and amyloid in the brain of individuals with Parkinson's
 Disease (PD) and otherwise healthy older people. PD participants will undergo repeat brain
 imaging to assess amyloid accumulation two years after their first brain imaging session. All
 participants will undergo examinations to assess their motor function, and asked questions to
 assess their mood and thinking.
Parkinson's disease (PD) is a common problem of older people often causing significant
 problems with thinking and memory. Abnormal accumulation within in the brain of a protein
 called amyloid is felt to contribute to impaired thinking and memory in PD. Excessive
 accumulation of this protein is also involved in Alzheimer disease (AD) and may influence
 thinking and memory in otherwise healthy older people. Recent evidence suggests that changes
 in the amount of another brain chemical, serotonin, influences the amount of amyloid
 accumulating in the brains of people with PD and otherwise healthy older people. The purpose
 of this study is to determine if changes in brain serotonin affects the accumulation of
 amyloid in the brain. The investigators use brain imaging methods to measure the amount of
 serotonin and amyloid in the brain of individuals with PD and otherwise healthy older people.
 PD participants will undergo repeat brain imaging to assess amyloid accumulation 2 years
 after their first brain imaging session. All participants will undergo examinations to assess
 their motor function, and asked questions to assess their mood and thinking.
Inclusion Criteria:

 -  Persons who have been diagnosed with Parkinson disease age 45 years and older are
 eligible to participate in this study.

 -  Healthy older individuals (ages 60-80) without neurologic problems are eligible to
 participate.

 Exclusion Criteria:

 -  Individuals using some drugs cannot participate. These include anti-depressant
 medications, buproprion, or St. John's Wort, as well as dopamine antagonist
 medications.

 -  Women of childbearing age may not participate.

 -  Individuals unable to have MRI scans because of a pacemaker or metal fragments may not
 participate.

 -  Individuals with a history of stroke may not participate. People with any
 contraindication of PET imaging such as previous participation in research procedures
 involving ionizing radiation may not be eligible to participate in this study.