Addiction-related memories are exceptionally strong and stable, suggesting that addictive drugs remodel the brain’s circuitry in a prominent and lasting way. In the past decade, researchers have used mouse models to unravel how cellular changes in the nucleus accumbens (NAc), a brain structure involved in action selection associated with arousal and reward, may contribute to addiction-related behavior. Whereas neuronal remodeling in the NAc explains a wide range of addictive behaviors, it is not required for all of them, according to a study.