For the past several decades researchers have put forth concerted efforts to investigate the effects of drugs of abuse on brain function with the ultimate goal of developing medications useful in terminating drug use and preventing relapse. The progression from initial drug use to drug dependence involves complex, multifaceted neural adaptations that encompass molecular changes at the cellular level within several different brain circuits. From studies involving human subjects and animal models, drugs of abuse are known to act on the cortico-limbic network (see Figure 1) that governs reward (mesolimbic dopaminergic pathway), learning and memory (hippocampus), emotion (amygdala), and executive functions (prefrontal cortex). Our understanding, at this point, remains limited regarding how drug-related experiences are encoded in the brain and their relationship to synaptic plasticity and the development of addictions.
