NCT03989518

The Link Between Mental Imagery and the Reduction of Fear in Imaginal Extinction

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 60 (actual)
• Sponsor: Uppsala University · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

Imaginal exposure is a widely used psychological treatment technique. Imaginal extinction is an experimental analogue of imaginal exposure, that allows the study of this treatment technique under controlled circumstances (Agren, Björkstrand, \& Fredrikson, 2017). During imaginal extinction, experimentally induced fear is diminished through repeated exposure to mental imagery of the feared (conditioned) stimulus. However, it is not known to what extent fear reduction depends on the mental imagery produced during this procedure. A better understanding of the mechanisms driving the effects of imaginal exposure and the factors moderating fear reduction could have significant clinical utility, by suggesting mechanistically informed ways to improve this treatment.

Detailed description

The study takes part over three consecutive days, with fear conditioning to visual stimuli on day 1, imaginal extinction on day 2, and a fear reinstatement procedure, again to visual stimuli, on day 3. Skin conductance is used to measure fear responses. Participants' are randomized to receive conditioning, extinction and reinstatement with either complex or simple stimuli. During imaginal extinction, imagery of each experimental stimulus is prompted through different verbal instructions.

Conditions

• Healthy Subjects

Interventions

Type	Name	Description
BEHAVIORAL	Fear acquisition	Day 1. Participants are exposed to two different visual stimuli. One of these stimuli is paired with a mild electric shock (i.e. conditioned stimuli).
BEHAVIORAL	Imaginal extinction	Day 2 (24 hours after Day 1). Participants are exposed to mental imagery of the stimuli used during fear conditioning. Imagery is prompted through different verbal instructions presented in a pseudo-randomized order. No shocks are delivered. Prior to imaginal extinction, participants receive task specific training.
BEHAVIORAL	Reinstatement	Day 3 (48 h after day1). Participants are exposed to the same stimuli used during fear conditioning (day 1) and imaginal extinction (day 2). Two unsignaled shocks are delivered at the beginning of the experiment, prior to the presentation of the first visual stimulus. No further shocks are delivered. This procedure allows the study of long term effects of imaginal extinction.

Timeline

• Start date: 2019-02-25
• Primary completion: 2019-10-30
• Completion: 2019-10-30
• First posted: 2019-06-18
• Last updated: 2019-11-04

Locations

1 site across 1 country: Sweden