Behavioral mechanisms of oxycodone's effects in female and male rats: Reinforcement delay and impulsive choice.

μ-Opioid agonists (e.g., morphine) typically increase which has been interpreted as an opioid-induced increase in sensitivity to reinforcement delay.

Effects of oxycodone on sensitivity to reinforcement magnitude: implications for effects of opioids on impulsive and risky choice.

Opioid addiction/dependence is associated with impulsive and risky behavior. Moreover, opioids can increase impulsive choice in preclinical studies with nonhumans. The objective of this study was to investigate a potential behavioral mechanism of opioids: a change in the impact of reinforcement magnitude on choice.