Extinction in multiple virtual reality contexts diminishes fear reinstatement in humans

Abstract

Although conditioned fear can be effectively extinguished by unreinforced exposure to a threat cue, fear responses tend to return when the cue is encountered some time after extinction (spontaneous recovery), in a novel environment (renewal), or following presentation of an aversive stimulus (reinstatement). As extinction represents a context-dependent form of new learning, one possible strategy to circumvent the return of fear is to conduct extinction across several environments. Here, we tested the effectiveness of multiple context extinction in a two-day fear conditioning experiment using 3-D virtual reality technology to create immersive, ecologically-valid context changes. Fear-potentiated startle served as the dependent measure. All three experimental groups initially acquired fear in a single context. A multiple extinction group then underwent extinction in three contexts, while a second group underwent extinction in the acquisition context and a third group underwent extinction in a single different context. All groups returned 24 hours later to test for return of fear in the extinction context (spontaneous recovery) and a novel context (renewal and reinstatement/test). Extinction in multiple contexts attenuated reinstatement of fear but did not reduce spontaneous recovery. Results from fear renewal were tendential. Our findings suggest that multi-context extinction can reduce fear relapse following an aversive event – an event that often induces return of fear in real-world settings -- and provides empirical support for conducting exposure-based clinical treatments across a variety of environments.

Novelty-Facilitated Extinction: Providing a Novel Outcome in Place of an Expected Threat Diminishes Recovery of Defensive Responses

“…Future experiments will also be needed to determine how NFE targets other post-extinction phenomena, including contextual renewal and reinstatement. Future studies in humans should consider incorporating immersive virtual reality to emulate characteristics of real world environments (48). Finally, an intriguing possibility is that NFE transforms the CS+ into a conditioned inhibitor (i.e., safety signal).…”

Rethinking Extinction

“…Recently, Dunsmoor et al (2014) used novel events to augment extinction by replacing, rather than simply omitting, an aversive electrical shock US with a surprising non-aversive outcome (a tone). Compared to groups that received traditional extinction training through shock omission alone, this modified extinction paradigm, referred to as novelty-facilitated extinction , reduced spontaneous recovery of conditioned skin conductance responses in humans and freezing in rats at a 24-hour test of extinction retention.…”

Circuit dysregulation and circuit-based treatments in posttraumatic stress disorder

“…Interestingly, if adult neurogenesis in the dentate gyrus enhances contextual processing in hippocampus by improving one’s ability to separate harm from safety [73, 74], this might explain at least partially the therapeutic efficacy of antidepressants shown to enhance hippocampal neurogenesis [75], in treatment of PTSD symptoms. Conducting extinction training across different contexts [e.g., 76], is another potential strategy to enhance contextual processing and hippocampo-prefrontal function, with some data suggesting that sleep quality might be an important variable in this process [77]. Finally, recent reports on the efficacy of mindfulness-based therapies suggest that focusing on immediate physiological and spatial context might be beneficial in “exercising” context awareness [78].…”