Drug reward memory: Implication from drug-induced conditioned place preference model

Drug addiction is a chronic, relapsing brain disorder, which develops, in part, because of aberrant learning and memory. Accumulative studies during recent decades demonstrated that addictive drug hijacks the normal memory circuit in the brain to form a long-lasting drug reward memory, which determines relapse to addictive drug. In this review, we will describe what has been learned about drug reward memory, especially focused on one of the associative drug reward memory models, drug- induced conditioned place preference. Drug reward memory is a dynamic process, which consists of several stages, including acquisition, consolidation, maintenance, retrieval, reconsolidation and extinction. Interventions with pharmacological in these memory processes will differentially regulate drug reward memory. Furthermore, the recently developed novel pure behavioral procedure according to the hypothesis of memory processes, e.g. post-retrieval extinction, could erase drug reward memory, which shows more advantages than the pharmacological medications that used in memory studies. Finally, we discussed two major methodological issues in drug reward memory, procedure and timing, which should be carefully considered when designing the related studies and interpreting the results from related studies. So far, it is not sure whether it is feasible to develop a pharmacological medication that only erases drug reward memory without impairing normal memories, we propose that inhibition of drug reward memory would be a good strategy to limit the risk of relapse to addictive drug. Although current findings on drug reward memory benefits little for treatment of drug addiction, the ongoing studies on drug reward memory will provide a promising strategy for reducing the risk of relapse to addictive drug.