Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Increased microglial activation plays an important role in the diffuse brain changes associated with neurodegeneration in Parkinson's disease (PD). Microglial activation is present in the post-mortem brains of PD in the regions associated with cognition. Microglial activation also precedes neuronal degeneration in animal models of PD. These observations suggest that quantification of microglial activation in vivo may serve as a new biomarker for early detection of cognitive impairment in PD. Previous neuroimaging studies using Positron Emission Tomography (PET) supported diffuse microglial activation including in the brain regions relevant to cognition. However, these studies did not include PD patients with cognitive impairment. Also the limitations of the PET radiotracer and analysis method warrant further studies. Therefore, I will measure microglial activation in PD patients with cognitive impairment using a PET radiotracer that our group has developed to overcome the limitations of the previous radiotracer, and investigate the relationships (1) between microglial activation and cognitive impairment as well as (2) between microglial activation and other neuroimaging data. PD is the second most common neurodegenerative illness, affecting more than 100,000 Canadians. Cognitive impairment is common in PD, and is considered to be one of the important risk factors for developing dementia: At least 80% of PD patients will develop dementia after 10 years of having the disease. My proposed study will provide in vivo the first reliable evidence of increased microglial activation using a novel PET radiotracer in PD patients with cognitive impairment, and demonstrate the relationships between microglial activation and cognitive impairment as well as other neuroimaging data. It will be used as a new biomarker for early detection of cognitive impairment, which will help to further confirm the relationships between microglial activation, MCI and development of dementia.