Dopamine and Risky-Decision Making

Parkinson’s disease is a neurodegenerative disorder that arises when a substantial number of dopamine-producing neurons deteriorate. The loss of these cells results in a number of brain regions receiving less than the normal amount of dopamine (DA). In addition to the motor symptoms of the disease, many patients with Parkinson’s disease exhibit difficulties with cognitive tasks. Patients can take a variety of drug therapies that increase DA brain levels or directly stimulate DA receptors in order to alleviate motor and cognitive symptoms. However, recent studies have shown that a number of patients with Parkinson’s disease have developed pathological gambling, which appears to be related to the DA agonist drug therapy they are taking. The gambling symptoms appear after the induction of (or increase in) the dose the DA agonist medication and disappear when the medication is decreased or halted. Jennifer St. Onge is researching the link between pathological gambling and increased DA activity in the brain by studying how risk-based decision making is altered by manipulations of DA transmission using experimental animals. Her research will help clarify whether pathological gambling and risk taking behaviour observed in some patients with Parkinson’s disease is the result of DA agonist drug therapy. This study may facilitate closer monitoring of drug doses and the development of novel drugs that could treat motor symptoms of the disease without altering decision making.