Changes in the time of day of conditioning with respect to the pre-exposure interfere with the latent inhibition of conditioned taste aversion in rats.

In rats, the reduction of the magnitude of a conditioned taste aversion (CTA) that occurs after taste pre-exposures (that is, the latent inhibition of CTA) can be attenuated by contextual changes of the external cues in the conditioning stage. Similarly, circadian internal cues such as those induced by the time of day may also modulate the magnitude of the taste aversion. Under a long period of temporal-contextual habituation, the latent inhibition of CTA is reduced if the pre-exposure and conditioning stages occur at different times of day. However, it is unknown if this effect is consistent when different changes in the time of day of conditioning with respect to the pre-exposure are compared. In this study, the effect of two different changes in the time of day of conditioning (one from morning to evening, and one from evening to morning) on the latent inhibition of CTA was compared with the response of a typical latent inhibition group without temporal change between stages, and with control groups without pre-exposures. The results indicate that the latent inhibition of CTA of both groups with temporal change between pre-exposure and conditioning is significantly reduced when compared with the latent inhibition of the group without temporal change. These findings suggest that the temporal context may be a critical cue for the latent inhibition of CTA, and they show that different changes in the time of day of conditioning interfere similarly with this learning.