Abstract
The basal ganglia are important neural substrates that control not only motor functions but also advanced brain functions and dysfunctions including decision making and drug addiction. In the basal ganglia circuit, there are two important pathways; the direct and indirect striatal pathways, which are controlled by dopamine. Various techniques that activate or inactive selectively the direct or indirect pathway neurons have revealed the function of each pathway. Here we review the basal ganglia circuit mechanisms in decision making and drug addiction, especially the dopaminergic modulation of the direct and indirect pathways. These circuit mechanisms will give us insights into the pathophysiology of mental disorders including drug addiction.
