The role of test context in latent inhibition of conditioned inhibition: Part of a search for general principles of associative interference

Abstract

In two lick suppression experiments with rats, we assessed interference with behavior indicative of conditioned inhibition by a latent inhibition treatment as a function of test context. We asked what effect the test context has, given identical latent inhibition treatments in Phase 1 and identical conditioned inhibition trainings in Phase 2. In Experiment 1, an AAA versus AAB context-shift design determined that the latent inhibition treatment in Phase 1 attenuated behavior indicative of the conditioned inhibition training administered in Phase 2, regardless of the test context, which could reflect a failure to either acquire or express conditioned inhibition. In Experiment 2, an ABA versus ABB design showed that test performance in Contexts A and B reflected the treatments that had been administered in those contexts (i.e., conditioned inhibition was observed in Context B but not A), which could reflect either the context specificity of either latent inhibition or conditioned inhibition. In either case, latent inhibition of conditioned inhibition training in at least some situations was seen to reflect an expression deficit rather than an acquisition deficit. These data, in conjunction with prior reports, suggest that latent inhibition is relatively specific to the context in which it was administered, whereas conditioned inhibition is specific to its training context only when it is the second-learned relationship concerning the target cue. These experiments are part of a larger effort to delineate control by the test context of two-phase associative interference, as a function of the nature of target training and the nature of interference training.

Figure 1. Results of Experiment 1

Mean times to complete 5 cumulative seconds of drinking in the presence of the target test compound. Therefore, 0.7 log s is the lowest possible score. Higher scores represent stronger conditioned suppression. Error bars represent standard error of the mean. See text and Table 1 for details.

Figure 2. Results of Experiment 2

Mean times to complete 5 cumulative seconds of drinking in the presence of the target test compound. Therefore, 0.7 log s is the lowest possible score. Higher scores represent stronger conditioned suppression. Error bars represent standard error of the mean. See text and Table 2 for details.