Two ways to deepen extinction and the difference between them.

Abstract

A series of experiments used rats to compare and contrast the effects of subjecting an already extinguished target conditioned stimulus (CS) to additional extinction in compound with either another extinguished or a nonextinguished CS. Exposure to either compound restored responding and their extinction deepened the loss of fear responses (freezing) to the target relative to a CS given equivalent extinction in isolation. This deepening was greater to the target extinguished in compound with the nonextinguished than with the extinguished CS. Summation tests showed that the target suppressed responding to an excitor or an excitatory context when it had been extinguished in compound with a nonextinguished but not with an extinguished CS. The results were interpreted to mean that additional extinction in compound with another extinguished CS resulted in the target acquiring the additional inhibition required to more fully oppose its original excitation. In contrast, additional extinction in compound with a nonextinguished CS resulted in the target acquiring not only the additional inhibition required to oppose its original excitation but also that of the nonextinguished CS, thereby converting the target into a net inhibitor.

Compound stimulus extinction reduces spontaneous recovery in humans

“…In both versions, the compound CS presentation restores conditioned responding following CS alone extinction trials, providing evidence that the compound presentation generates renewed expectation of the US. Both versions also diminished fear recovery in laboratory animals, providing further evidence for deepened extinction (Leung et al 2012). In line with prediction error models of associative learning (Rescorla and Wagner 1972), the unexpected absence of the US deepens the loss of associative value for the extinguished CS below the level attained during CS alone extinction trials.…”

“…Experiments in rats have demonstrated the effectiveness of deepened extinction in reducing post-extinction fear recovery (Rescorla 2006;Leung et al 2012;McConnell et al 2013), recovery of lever press responding (Janak and Corbit 2011) and recovery of cocaine seeking . There are clinical examples of multiple cue exposure in humans as well; for example, therapies that initially expose a patient with spider phobia to different spiders in isolation, followed by multiple spiders at the same time (for review, see Craske et al 2014).…”

“…There are clinical examples of multiple cue exposure in humans as well; for example, therapies that initially expose a patient with spider phobia to different spiders in isolation, followed by multiple spiders at the same time (for review, see Craske et al 2014). Leung et al (2012), directly compared two forms of deepened extinction, and found that the Reberg (1972) method of combining an extinguished CS with a nonextinguished CS resulted in stronger inhibition of the conditioned response than the Hendry (1982) method of combining multiple extinguished CSs.…”

“…Animal studies on deepened extinction show that compound stimulus presentation temporarily enhances conditioned responding following CS alone extinction trials (Rescorla 2006;Leung et al 2012). We therefore compared the conditioned responses from the first trial of Extinction 2 to address whether compound stimulus extinction increased responding in the DE versus the CTL group.…”

“…Recently, Culver et al (2014) provided evidence that the Hendry (1982) method of extinguishing two CSs in isolation prior to compound extinction diminished post-extinction recovery and reinstatement following unsignaled presentations of an aversive human scream (US). Here, we used intermodal cues (visual and auditory) and a potentially stronger US (i.e., electrical shock) to explore the effect of compound extinction with an extinguished and nonextinguished cue (Reberg 1972) on spontaneous recovery and reinstatement in humans, which animal models demonstrate is a more robust procedure to deepen extinction (Leung et al 2012).…”