Drug addiction is a chronic psychiatric condition of compulsive drug seeking and taking despite severe social and physical repercussions [1–4]. One of the most clinically challenging aspects of addiction is its persistence even after long periods of drug abstinence, which is highlighted by high rates of dug relapse for most addictive drugs. All drugs of abuse in some way converge on the mesolimbic dopamine system, a key brain circuit involved in reward [1, 3]. This circuit normally helps determine how rewarding certain environmental stimuli are and functions to reinforce evolutionally favorable activities, such as eating fatty foods or sex [5]. The dopaminergic cells of the ventral tegmental area (VTA) project into the forebrain and bathe several key limbic structures with dopamine, including the nucleus accumbens (NAc). The NAc integrates inputs from the prefrontal cortex (PFC), amygdala, hippocampus, and several other limbic structures to synthesize the appropriate synaptic and behavioral responses to rewarding stimuli including drugs of abuse [1, 3]. Addictive drugs such as cocaine have been shown to induce long-lasting structural, electrophysiological, and transcriptional changes in the NAc, and some
