Neuroanatomical Structures Underlying the Extinction of Drug-Seeking Behavior

This review summarizes current knowledge about the neurobiological components underlying the extinction of drug-associated memories and how they may contribute to the treatment of drug addiction. Evidence suggests that extinction learning is not the forgetting, or unlearning, of the associations between external stimuli and drug effects, but that new reinforcer expectancies are necessary for extinction of drug-seeking behavior to take place. Several theories suggest that addiction is a disorder of learning and memory, and recent evidence indicates that the brain circuits, neurotransmitters, and signal transduction mechanisms that underlie drug addiction are similar to those that mediate learning and memory processes. According to these theories, drug addiction results from repeated drug use and the formation of lasting associations between a drug’s effects, withdrawal symptoms, and the environmental cues and contexts within which they are experienced. Unfortunately, standard behavioral modification techniques, such as cue exposure therapy, have shown only moderate efficacy in reducing and/or extinguishing the salience of drug-associated cues and contexts. Therefore, a greater understanding of the neurobiological mechanisms involved in the extinction of drug-related memories could provide novel therapeutic interventions for the treatment of drug addiction.