Salinas J A, Packard M G, McGaugh J L
Center for the Neurobiology of Learning and Memory, University of California at Irvine 92717-3800.
Behav Brain Res. 1993 Dec 31;59(1-2):153-9. doi: 10.1016/0166-4328(93)90162-j.
The present study used a reward reduction paradigm to examine the role of the amygdala in memory for reduction in reward magnitude. Male Sprague-Dawley rats were implanted with bilateral amygdala cannulae and trained to run a straight alley (6 trials/day) for either ten or one 45-mg food pellets. On Day 10 of training, half the animals in the 10 pellet reward group were shifted to a one pellet reward. Immediately following shifted trials, the animals received an intra-amygdala injection of either a 2% lidocaine solution or phosphate buffer (0.5 microliter/side). Shifted training continued for 2 more days and no further injections were given. Shifted animals that received a buffer injection displayed a sharp increase in response latencies compared to unshifted controls on the second day of shifted training. In contrast, shifted animals that received intra-amygdala injections of lidocaine exhibited significantly lower latencies compared to the shifted vehicle group on the second day of shifted training. The findings indicate that post-training inactivation of the amygdala attenuates the response to reward reduction, suggesting that the amygdala modulates the storage for a reduction in reward magnitude.
本研究采用奖励减少范式来检验杏仁核在奖励幅度降低记忆中的作用。雄性Sprague-Dawley大鼠双侧植入杏仁核套管，并训练它们在直道上奔跑（每天6次试验），以获取10颗或1颗45毫克的食物颗粒。在训练的第10天，10颗颗粒奖励组中的一半动物被改为1颗颗粒奖励。在转换试验后立即给动物杏仁核内注射2%利多卡因溶液或磷酸盐缓冲液（每侧0.5微升）。转换训练持续2天，不再进行进一步注射。接受缓冲液注射的转换动物在转换训练的第二天与未转换的对照组相比，反应潜伏期急剧增加。相反，接受杏仁核内利多卡因注射的转换动物在转换训练的第二天与转换的载体组相比，潜伏期显著降低。研究结果表明，训练后杏仁核失活会减弱对奖励减少的反应，这表明杏仁核对奖励幅度降低的记忆存储有调节作用。
