Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Physiology

Supervisor

Dr. Penny MacDonald

2nd Supervisor

Dr. Adrian Owen

Joint Supervisor

Abstract

Cognitive impairment is recognized in Parkinson’s disease (PD). Understanding striatum-mediated cognitive functions will help elucidate some of these abnormalities. Learning is often impaired by dopaminergic medication. However, dorsal striatum (DS) has been implicated in learning; an unexpected result given that dopaminergic therapy, the gold standard treatment for PD, remediates DS functioning. In two separate experiments, stimulus-response association learning and decision-making were examined in healthy individuals using functional magnetic resonance imaging (fMRI), and in PD patients using behavioural methods. In Experiment 1, healthy individuals completed a stimulus-response learning task, and brain regions associated with learning versus decision-making were investigated using fMRI. In Experiment 2, patients with PD completed a similar task on and off their dopaminergic medication. Results from both experiments suggest that DS mediates decision-making and not learning. This greater understanding of striatum-mediated cognition will ultimately prompt clinicians to devise medication strategies that consider both motor and cognitive symptoms of PD.


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