Time and context effects on performance in a Pavlovian discrimination reversal.

Five conditioned suppression experiments with rats explored retention interval and context effects in discrimination reversal learning. In the discrimination phase, a tone (T) was paired with shock, and a houselight-off stimulus (L) was presented alone; in the reversal phase, T was extinguished and L was paired with shock. Discrimination training made L a latent inhibitor but not a conditioned inhibitor. A 28-day delay after the reversal caused spontaneous recovery to T but had no effect on L. A context switch before the reversal caused more rapid conditioning to L but did not affect extinction to T. A return to the original context after the reversal had occurred in a different context renewed suppression to T and latent inhibition to L; contextual control was still strong 21 days later