CHRNB2

The underlying goal of this study is to assess [123I] 5-IA and SPECT imaging as a tool to detect nicotinic receptor activity in the brain of PD patients. All study procedures will be conducted at the Institute for Neurodegenerative Disorders (IND) and Molecular NeuroImaging (MNI) in New Haven, CT. Approximately 10 patients with a diagnosis of PD without cognitive changes will be recruited to participate in this study. Patients will be eligible to participate if they have a diagnosis of PD of more than 2 years duration and have no significant cognitive changes.

The purpose of this study is to use brain imaging technology to examine the role of certain brain chemicals in individuals with Alzheimer's disease (AD) and in healthy volunteers.
Cognitive dysfunction in people with AD is thought to arise from decreased chemical activity in specific parts of the brain. Decreases in alpha4beta2 nicotinic acetycholine receptors (nAChRs) have been found in the brains of people who died with AD; however, the status of this receptor system in living brains remains unclear. This study will use single photon emission computed tomography (SPECT) to study this receptor system in people with AD who have mild to moderate dementia and in healthy volunteers. In addition, this study will examine the relationship between cognitive dysfunction and nAChR deficits in the brains of individuals with AD.
Participants with AD will have four clinic visits; healthy volunteers will have three visits. At Visit 1, participants will undergo a medical history, physical examination, and laboratory tests. Healthy volunteers will have a Mini-Mental State Examination (MMSE) cognitive function test. Participants with AD will have a MMSE and measurement of the severity of their dementia.
During Visit 2, participants will undergo a magnetic resonance imaging (MRI) scan of the brain.
At Visit 3, participants will undergo SPECT imaging.
Only participants with AD will participate in Visit 4. During this visit, cognitive testing will be performed.