Neurobiological Basis of Drug Reward and Reinforcement.

Drugs of abuse interact with brain circuitry involved in reward and reinforcement, and it is thought that through these interactions drugs can gain influence over brain function, leading to maladaptive behavior. This chapter reviews the basic concepts of reward and reinforcement, with particular emphasis on positive and negative reinforcement and the differences between goal-directed and stimulus-driven ˵habitual″ behavior. The role of particular neurotransmitters and neural circuitry, most notably cortico-basal ganglia circuits, in reward, reinforcement, and drug addiction is then discussed. Several laboratory animal models of drug use are considered along with critical consideration of what constitutes an adequate ˵addiction″ model. The actions of addictive drugs within the brain reinforcement and reward circuitry are then reviewed, including information about the molecular targets of abused drugs, their actions on relevant circuitry, and their actions in the aforementioned laboratory animal models. Finally, the neurobiological underpinnings of drug use, abuse, and addiction are discussed, and some ideas are put forward about future research in this field. [ABSTRACT FROM AUTHOR]