Alain Dagher, MD, is a neurologist and neuroscientist who treats patients with Parkinson's disease (PD) and studies functional brain imaging. The overarching theme of his research is the function of the brain regions called basal ganglia and frontal lobes and the role of dopamine in cognition and emotion (predominantly in PD), drug addiction and obesity. He developed a method of measuring the release of dopamine in the human brain and applied this method to studies of the human reward system. These studies aim to uncover the basic mechanisms of dopamine effects and investigate individuals at risk of disease such as drug addiction and obesity. Dr. Dagher was among the first to publish on the subject of functional brain mapping in Parkinson's, the work he conducted using positron emission tomography. He has recently applied graph theory and related mathematical methods to the study of brain networks in PD.