Contextual modulation of simultaneous associations

Abstract

In four experiments with water-deprived rats, we examined the possibility that simultaneous associations between a conditioned stimulus (CS) and an unconditioned stimulus (US) were modulated or masked by context–US associations. In Experiment 1 we determined that simultaneous CS-US pairings administered in multiple contexts enhanced responding to the CS relative to training in a single context. A forward CS–US arrangement produced no such enhancement. In subsequent experiments, animals were trained in a single context. In Experiment 2, the number of CS–US pairings was varied and no inverse relationship between the response directly elicited by the training context and the response elicited by the CS was found. In Experiments 3 and 4, we detected no effect on the response to the CS of extensive exposure to the training context before or after simultaneous CS–US pairings, although such latent inhibition or extinction treatment reduced the response elicited by the context. In total, these results indicate that the response to a simultaneously trained CS may be modulated by its training context, but that the response to the CS does not simply vary inversely with the response potential of that context.