Rapid delivery of cocaine facilitates acquisition of self-administration in rats: An effect masked by paired stimuli

► In this study we examined the effects of infusion duration on cocaine self-administration in rats. ► We found that when a stimulus was associated with the cocaine infusion, infusion duration had little effect on the acquisition of cocaine self-administration. ► When no stimulus was associated with the cocaine infusion, cocaine self-administration was acquired only with the faster cocaine infusion. ► These results indicate that infusing a given dose of cocaine more rapidly reduces its ability to support self-administration, but drug-paired stimuli can mask this effect by enhancing the effectiveness of slow infusions.