Long-term retention of learning of single alternate reward series in rats

Abstract

The present study examined long-term retention of learning of single alternate reward series in rats. Rats were given seven trials in a straight runway daily. During acquisition training of 16 days, Group SA (single alternate) received a series of seven trials of RNRNRNR (R: reward, N: non-reward) daily, whereas Group RD (random) was given presentation of either of RNRNNRR, RNNRRNR, RRNNRNR, or RRNRNNR in blocks of four days. After retention interval of 23 days, both groups were trained with a single alternate series of RNRNRNR as a test for 16 days. Anticipation of reward events in the series was indexed by slower running in non-rewarded trials than in rewarded trials. Although differentiation in running speed between rewarded and non-rewarded runs was not evident at the end of the acquisition training, Group SA developed reward-anticipation performance significantly faster than Group RD during the test. The results suggest that rats can retain learning of the single alternate series for a long period.