Elysia A. Gauthier

nucleus accumbens morphine opioid withdrawal synaptic plasticity addiction Introduction Opioid use disorders are driven by both the rewarding euphoric states induced by opioids and the subsequent negative dysphoric states induced by withdrawal and abstinence (Evans and Cahill, 2016; Koob, 2020). It is postulated that this leads to repeating cycles of negative reinforcement by alleviating withdrawal symptoms with continued opioid use (Evans and Cahill, 2016; Koob, 2020).

Abstract Opioid exposure and withdrawal both cause adaptations in brain circuits that may contribute to abuse liability. These adaptations vary in magnitude and direction following different patterns of opioid exposure, but few studies have systematically manipulated the pattern of opioid administration while measuring neurobiological impact.