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

Parkinson's disease (PD) is typically known for its motor symptoms, however progressive cognitive decline is a common complication of the disease, with over 60% of PD patients impaired in one or more cognitive domains. Cognitive decline contributes to significant impairments, resulting in a poorer quality of life and higher levels of care dependency. Despite its significance, the neural basis cognitive decline in PD is poorly understood. PD motor progression has been well characterized by the loss of the neurotransmitter dopamine in the brain due to the death of dopamine-producing cells in the brain. New research suggests the loss of dopamine may also play a role in the cognitive decline of PD as well. A better understanding of the neural mechanisms involved in PD cognitive decline is an important prerequisite for improved therapeutic strategies. The proposed study will look at how dopamine regulation is affected in PD patients both with and without cognitive decline. Using a neuroimaging technique called positron emission tomography (PET), we will visualize the dopamine receptors in the brains of PD patients in vivo using a radiotracer that binds preferentially to one common type of dopamine receptor called the D2 receptor. Whole-brain network dysfunction of this dopamine receptor may have a role in cognitive decline and we will use graph theory analysis to investigate in vivo D2 communication patterns in the brains of PD patients. Uncovering the pathological mechanisms involved in PD cognitive decline can have many benefits, such as 1) finding an early indicator of cognitive decline 2) discovering new treatment options for present PD patients and 3) possible new development of future preventative measures to slow the progression into PD dementia. Additionally, validation of this approach will allow for the use of network analysis tools for a wider range of neurotransmitters to measure dysfunctional brain activation patterns in other neurotransmitter systems.