Retroactive interference of a learnt action-outcome association by exposure to a stimulus-outcome learning experience

The current study used the protocol established to produce retroactive interference (RI) in contextual memory paradigms and applied it to an appetitive learning setting. Rats were first subjected to the learning of an operant conditioning, action-outcome (A-O) association and were tested in a probe (A-O probe) session the following day. Rats that experienced an interpolated, classical conditioning, stimulus-outcome (S-O) learning experience performed more poorly in the probe session than those that did not undergo this experience. The S-O learning experience had therefore retroactively interfered with the A-O task. The degree of interference also varied with the amount of time lag between the three (A-O, S-O and the A-O probe) conditions. The current study is the first to show evidence of RI by an S-O learning experience on a recently learnt A-O association. These results are similar to those from hippocampal-dependent learning paradigms and indicate that interference of memory consolidation in an appetitive learning paradigm can be produced by an intervening task that is behaviourally distinct from the initial learning experience.