Protection from extinction by a conditioned inhibitor

The phenomenon of protection from extinction (PFE) of a conditioned stimulus (CS) by a conditioned inhibitor (CI) has not been yet unequivocally demonstrated for the CS-CI compound in which the CS precedes the onset of the CI. Preliminary data from a project addressed to this problem strongly indicate that PFE is a real and robust phenomenon. Moreover, the protection is demonstrated not only for the CS duration overlapping with the CI but also for the early part of the CS which is not prevented by the CI from eliciting a conditioned response. The review of a few theories of conditioning suggests that the phenomenon of PFE is theoretically acceptable and predicted within the framework of any hypothetical mechanism which allows for post-trial "processing" or "consolidation" of information acquired during the trial.