Context and performance in aversive-to-appetitive and appetitive-to-aversive transfer

Abstract

Three experiments with rat subjects examined the effects of contextual stimuli on performance in Pavlovian aversive-to-appetitive and appetitive-to-aversive transfer. A 30-s tone conditioned stimulus (CS) was first paired with either a shock or food pellet unconditioned stimulus (US) in one phase and then paired with the other US in a subsequent phase. Aversive and appetitive conditioning were indexed by the observation of freezing and headjerking, respectively. In aversive-appetitive transfer (Experiment 1), a context switch following Phase 1 aversive conditioning reduced the retarded appetitive conditioning ordinarily observed in Phase 2. In addition, a return to the Phase 1 context after completion of Phase 2 caused renewed Phase 1 responding and decreased Phase 2 responding. In appetitive-aversive transfer (Experiments 2 and 3), a context switch following Phase 1 appetitive conditioning had no effect because neither positive nor negative transfer with Phase 2 aversive conditioning was observed in this situation. However, a return to the Phase 1 conditioning context after completion of Phase 2 caused renewed Phase 1 responding at 1- and 28-day retention intervals (Experiment 2). These results are consistent with a role for context as a retrieval cue for memories corresponding to different phases. This view is discussed along with more traditional associative perspectives on contextual control.