Instrumental outcome devaluation with representation-mediated conditioning.

In three experiments, rats were trained to perform two instrumental behaviours (R1 and R2) in the presence of discriminative stimuli (Sd1 and Sd2, respectively) to obtain a common food outcome (O1). Acquisition of the two discriminations was followed by switching the outcome accompanying R2 performance from O1 to a new one (O2). Experiment 1 showed paired presentations of O2 with a lithium chloride (LiCl) injection resulted in a reduction in the R2 performance. In the subsequent two experiments, each Sd was paired with LiCl injection and its effects on outcome consumption and instrumental performance were investigated. A reduction in the O2 consumption subsequent to the Sd devaluation was found in Experiments 2 and 3. Experiment 3 revealed a reduced R2 performance in an extinction test, following the animals' consummatory access to the outcomes in training context. These results demonstrate representation-mediated outcome devaluation in the course of the Sd devaluation.