Parkinson’s disease is a chronic, progressive disorder that affects about 100,000 Canadians, at an annual cost of more than $2.5 billion. The disease involves loss of both brain cells and chemicals that modulate communications between brain cells – causing not only motor symptoms of tremor, stiffness, and slow movements but also cognitive and behavioural changes. Conventional drug therapy for Parkinson’s disease replaces dopamine in the brain. Although most motor deficits usually improve after therapy, more than 50 percent of patients (particularly those in the later stages of the disease) may develop difficult problems, such as involuntary movements, dementia and psychosis. Dr. Chong Lee is studying neural mechanisms of these complications, which are resulting from the disease itself or the chronic use of Parkinson’s drugs. Dr. Lee is also evaluating the effectiveness of neuro-protective treatment, a strategy to prolong the survival of injured cells and slow the progression of Parkinson’s disease. He ultimately aims to develop strategies to treat dementia and behavioural symptoms of the disease and to reduce or prevent treatment-induced complications in patients with Parkinson’s disease.