Behavioral and neurobiological mechanisms of extinction in Pavlovian and instrumental learning

Abstract

This article reviews research on the behavioral and neural mechanisms of extinction as it is represented in both Pavlovian and instrumental learning. In Pavlovian extinction, repeated presentation of a signal without its reinforcer weakens behavior evoked by the signal; in instrumental extinction, repeated occurrence of a voluntary action without its reinforcer weakens the strength of the action. In either case, contemporary research at both the behavioral and neural levels of analysis has been guided by a set of extinction principles that were first generated by research conducted at the behavioral level. The review discusses these principles and illustrates how they have informed the study of both Pavlovian and instrumental extinction. It shows that behavioral and neurobiological research efforts have been tightly linked and that their results are readily integrated. Pavlovian and instrumental extinction are also controlled by compatible behavioral and neural processes. Since many behavioral effects observed in extinction can be multiply determined, we suggest that the current close connection between behavioral-level and neural-level analyses will need to continue.

Evidence for the involvement of extinction-associated inhibitory learning in the forced swimming test

“…The observation that immediate post-extinction manipulation of a memory system promotes recovery of the extinguished escape response is in in line with convincing evidence that extinction training promotes new learning that is consolidated and can be retrieved as long-term memory [41][42][43]. Moreover, previous reports point to a main role of DLS in extinction of procedural learning in rats [44,45] and blockade of DLS mGluR5 metabrotropic receptors has been shown to prevent the development of the direct inhibitory context -response association in extinction of instrumental learning [46].…”

“…During their first experience with FST, rodents express species-typical responses aimed at escaping (rapid swimming around, struggle to climb the wall of the tank), and because this outcome is prevented in the FST apparatus, the responses are not reinforced, as in extinction training. Moreover, extinguished responses typically reappear if subjects are tested in an environment different from the one used for extinction training, a phenomena known as 'renewal' [42,50]. Similarly, the inhibition of defensive responses acquired through experience with a stressor that cannot be avoided, escaped or controlled, is still observable 1week later only if rats are re-exposed to the same apparatus [51].…”

Inhibition of estradiol synthesis impairs fear extinction in male rats

“…This phenomenon occurs when a memory is formed under a certain state and can only be recalled when again in that same state (Todd et al 2014). Rats received a s.c. injection of FAD or vehicle 30 min prior to extinction training, and then received another s.c. injection of FAD or vehicle 30 min prior to extinction recall, producing four groups: VehVeh (i.e., vehicle prior to extinction training and vehicle prior to extinction recall), FAD-Veh (i.e., FAD prior to extinction training and vehicle prior to extinction recall), Veh-FAD (i.e., vehicle prior to extinction training and FAD prior to extinction recall), and FAD-FAD (i.e., FAD prior to extinction training and FAD prior to extinction recall).…”

A Functional Model of Fast Action Selection Guided by Emotional Stimuli

“…This acquired connectivity remains to be investigated for other phenomena, including the fundamental role of context in extinction. Interestingly, such conflicting information about a cue in different phases of an experiment, which hinders one another afterwards, fits into the global theory called interference paradigm [44].…”

“…Responding to a cue previously associated with a reinforcer decreases when this cue is then presented repeatedly alone, a behavioral feature known as extinction [44]. To account for this effect, the absence of an expected reinforcer can be implemented in a way similar to GP counter-conditioning by growing an extra path stimulated by a 'noStim'-DE, and competing with the reinforcer (Figure 3).…”