Facilitating effects of pre- and posttrial amphetamine administration on discrimination learning in mice

Two experiments investigated the effects ofd-amphetamine on food-rewarded visual discrimination learning in mice. The findings of Experiment 1 indicate that degree of facilitation learning obtained with posttrial i.p. injections varied with dose: Facilitation was obtained with doses ranging from 0.25 to 2.0 mg/kg, but not with a higher dose (2.5 mg/kg). The findings of Experiment 2 indicate that degree of facilitation varies with time of administration. With two doses (0.5 and 2.0 mg/kg) facilitation was obtained with injections given up to 30 minutes before training or immediately after daily training. No significant effect was obtained with injection given 15 minutes after training. The findings are interpreted as providing further support for the view that amphetamine facilitates learning by affecting time-dependent memory storage processes.This research was supported in part by Research Grant MH-12526 from the National Institute of Mental Health, United States Public Health Service.