PIs: Roger L Albin, MD
Our preliminary results indicate a global effect of key AMI node AC-I cholinergic denervation on cognitive functions. These cortical regions are key nodes of the COTC network and participate in higher level aspects of attentional function. We will confirm that AC-I denervation is associated with widespread cognitive deficits. Our established PD cohort, extensively characterized with dopaminergic and cholinergic PET, and with motor and cognitive assays, uniquely positions us to define the distinctive natural history of a PD subgroup based on a pathologic marker. Continued follow-up of this valuable cohort will assess if AC-I cholinergic denervation predicts significantly greater global cognitive decline. Quantification of cholinergic changes in the COTC subcortical and cortical (AC-I) network in this cohort will also allow the assessment that progressive cognitive changes coincide with more severe motor changes (aggressive or ‘malignant’ PD subtype). PET studies are costly and [18F]FEOBV is only operational in a handful of centers. A convenient, reliable predictor of AC-I cholinergic denervation is required to employ this phenotype as subgroup marker or stratifying method. We will capitalize on the thorough phenotyping of our cohort and apply more convenient MRI methods, complementing Project I analyses, to explore an accessible biomarker. Through collaboration with investigators at the University of Groningen (Netherlands), we have access to a similarly characterized and prospectively followed cohort of incident PD subjects who also undergo [18F]FEOBV PET. These subjects are part of the Dutch Parkinson and Cognition Study (DUPARC). This collaboration will enable us to rigorously test our hypotheses regarding the impacts and prognostic potential of AC-I cholinergic denervation and identification of a useful predictor in an independent replication cohort. Our Groningen colleagues agreed to share all phenotypic, MRI, and [18F]FEOBV imaging data to address, in parallel, the hypotheses driving Project III. These studies will identify a key substrate of cognitive impairments and predictor of more rapid cognitive decline in PwP.