Contextual control of the extinction of conditioned fear: Tests for the associative value of the context.

Abstract

Four conditioned suppression experiments examined the influence of contextual stimuli on the rat's fear of an extinguished conditioned stimulus (CS). When rats received pairings of a CS with shock in one context and then extinction of the CS in another context, fear of the CS was renewed when the CS was returned to and tested in the original context (Experiments 1 and 3). No such renewal was obtained when the CS was tested in a second context after extinction had occurred in the conditioning context (Experiment 4). In Experiment 2, shocks presented following extinction reinstated fear of the CS, but only if they were presented in the context in which the CS was tested. In each experiment, the associative properties of the contexts were independently assessed. Contextual excitation was assessed primarily with context-preference tests in which the rats chose to sit in either the target context or an adjoining side compartment. Contextual inhibition was assessed with summation tests. Although reinstatement was correlated with demonstrable contextual excitation present during testing, the renewal effect was not. Moreover, there was no evidence that contextual inhibition developed during extinction. The results suggest that fear of an extinguished CS can be affected by the excitatory strength of the context but that independently demonstrable contextual excitation or inhibition is not necessary for contexts to control that fear.

Mechanisms of fear extinction

“…For example, when animals first are trained to fear a light CS in context A, then receive extinction training to the light in context B, and finally are tested for fear to the light in either context A or context B, different outcomes are obtained: animals tested in context B (the same context where extinction training took place) exhibit little fear to the light, whereas animals tested in context A exhibit robust fear to the light. 28,32 A similar postextinction return of fear is observed when animals are tested in a third, novel context C following acquisition in context A and extinction in context B. 32,33 The renewal effect is not due to simple context conditioning 28,34 but rather appears to reflect an occasion-setting or modulatory role of context in gating performance to the CS.…”

“…28,32 A similar postextinction return of fear is observed when animals are tested in a third, novel context C following acquisition in context A and extinction in context B. 32,33 The renewal effect is not due to simple context conditioning 28,34 but rather appears to reflect an occasion-setting or modulatory role of context in gating performance to the CS. 35 Thus, rather than learning that 'now the cue is no longer paired with the shock', the animal learns that 'now, in this place, the cue is no longer paired with the shock'.…”

“…Subsequent work established that unsignaled US presentations must occur within the context in which animals ultimately are tested if recovery is to be observed, and that extinction (nonreinforced exposure) to that context between unsignaled US presentations and test attenuates fear recovery. 27,28 Thus, reinstatement seems to depend on context conditioning and is likely to involve summation of two fear-inducing tendencies, each behaviorally subthreshold when considered independently, but suprathreshold when combined (cf. Hendry 29 and Reberg 30 ): weak conditioning to context and residual net excitation to the extinguished CS.…”

Models and mechanisms of anxiety: evidence from startle studies

“…In animals, behavioral avoidance is a reliable measure of context conditioning (Bouton and King 1983). Given the choice between moving into a place where they previously received predictable and unpredictable shocks, rats will avoid the unpredictable context in favor of the predictable context (Odling-Smee 1975a;1975b).…”

Self-directedness, integration and higher cognition

“…If an animal learns a response association in a particular context and it is presented the stimulus in a very different context, response to the stimulus is normally significantly reduced (Gluck and Meyers, 2001: ch.7). Similarly an animal that is conditioned to a stimulus in context X, then has the conditioned response extinguished in a second context Y, will regain the response if the stimulus is presented again in context X (Bouton and King, 1983;Pearce and Bouton, 2001). The context serves as an occasion setter providing information to the animal about how it should respond to the stimulus.…”