The basal ganglia are involved in complex brain functions and are implicated in numerous neurological and psychiatric disorders. At the heart of both function and dysfunction of basal ganglia circuits is the interaction of dopamine and glutamate. Improved labeling, imaging, recording, and genetic manipulation approaches have yielded new information on how dopamine and glutamate interact to generate the circuit activity underpinning basal ganglia function. This volume synthesizes this research, presenting current insights on individual neurons and synapses, detailed circuit analysis, and learning and action functions of the basal ganglia. The book also discusses compromised dopamine–glutamate interaction in various disorders of basal ganglia function.