The problem with dopamineBut dopamine’s motivational trigger can work in the opposite way, too, Greider says. “We have also showed that the pattern of dopamine activity signals the bad feelings of withdrawal, and the motivation to avoid it.”As the mice became addicted to nicotine, the dopamine neurons began to signal both reward and aversiveness. The aversive signals become weaker over time, boosting the reward signal. Eventually, the mice seem to only feel reward — and avoid withdrawal instead of the nicotine itself.Understanding how aversion switches to reward may help develop therapies that capitalize on the disgusting aspects of smoking, even in long-time smokers, Greider says.“If we can eventually develop a drug treatment that shuts down the rewarding brain cells but leaves the sense of disgust active, then when a person smokes they will only feel disgust and they would hopefully be helped to quit forever,” she says.