Neural Mechanisms of Imaginal and in Vivo Exposure

NCT ID: NCT05193383

Last Updated: 2024-08-26

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 87 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-04-07
• Study Completion Date: 2023-03-01

Brief Summary

Imaginal exposure is a widely used and effective psychological treatment technique. Recent research suggests that neural activations and emotional responses during imaginal exposure are similar to those elicited during in vivo exposure. However, to the investigators knowledge, no direct comparison between in vivo and imaginal exposure has been performed during neuroimaging. This study compares neural activations and emotional responses during imaginal and in vivo exposure. This study also explores the generalizability of fear reduction achieved through imaginal exposure to fear responses elicited by in vivo stimuli, and vice versa, in a follow-up session approximately one week later. A better understanding of the mechanisms behind both types of exposure could have significant clinical utility, as well as elucidate the differences between fear created from outward stimuli and fear created from inward stimuli, such as mental imagery.

Detailed Description

The study includes participants fearful of spiders and entails two experimental sessions, roughly one week apart. The first session includes brain imaging using functional magnetic resonance imaging (fMRI). During the first session, participants will be randomized into one of two conditions - in vivo exposure or imaginal exposure. In the in vivo exposure condition, participants will be shown video clips of spiders (fearful stimuli) and leaves (neutral stimuli) in different situations. In the imaginal exposure condition, participants will be instructed to produce mental imagery of the corresponding stimuli used for in vivo exposure.

Previous research found that the brief exposure procedure used during session 1 produced a fear reduction when the procedure was repeated one week later. Thus, in order to conceptually replicate this finding, and to examine the generalizability of fear reduction, participants return roughly one week later for a follow-up session. In the follow-up session, participants undergo a similar exposure procedure as used in session 1, but with half of the stimuli in vivo and the other half of the stimuli as mental imagery. In this way, it can be studied whether fear reduction generalize from exposure modality to another. The effects of imaginal and in vivo exposure on avoidance behavior towards fear-provoking stimuli (spiders) will also be assessed using an approach-avoidance conflict paradigm, using pictures of spiders to probe spider fear.

The current study will also explore the impact of mental imagery vividness during imaginal exposure on fear reduction. Additionally, the study will assess if vividness level can predict the generalizability of the effects of imaginal exposure to fear-provoking stimuli (mental imagery of a spider) on subsequent fear responses to to in vivo stimuli (film clip of a spider) one week later.

Functional magnetic resonance imaging (7T) is used to measure neural activations (session 1). Skin conductance is used to measure arousal response (session 1 & 2). Subjective fear and mental imagery vividness ratings will also be collected.

Conditions

Fear of Spiders

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Imaginal exposure

Exposure to mental imagery including a fearful stimulus (spider) and corresponding scenes including a neutral stimulus (leaf)

Group Type: EXPERIMENTAL

Imaginal exposure

Intervention Type: BEHAVIORAL

Session 1 (Day 1): Participants receive repeated exposure to mental imagery of fear-provoking stimuli (spiders) and neutral stimuli (leaves) while undergoing brain imaging med fMRI.

Exposure

Intervention Type: BEHAVIORAL

Session 2 (Ca one week): Participants receive both imaginal and in vivo exposure to fear-provoking stimuli and neutral stimuli (both arms are exposed to both video clips (in vivo exposure) and mental imagery (imaginal exposure). Session 2 is conducted in the laboratory, i.e., no brain imaging.

Approach-avoidance conflict

Intervention Type: BEHAVIORAL

Session 2 (Ca one week): Spider fear is probed by an approach-avoidance conflict task. Participants can receive varying small rewards for watching pictures of spiders, or avoid the spider pictures at the cost of not receiving a reward (neutral pictures are shown instead).

In vivo exposure

Exposure to video clips including a fearful stimulus (spider) and corresponding clips including a neutral stimulus (leaf)

Group Type: EXPERIMENTAL

Exposure

Intervention Type: BEHAVIORAL

Session 2 (Ca one week): Participants receive both imaginal and in vivo exposure to fear-provoking stimuli and neutral stimuli (both arms are exposed to both video clips (in vivo exposure) and mental imagery (imaginal exposure). Session 2 is conducted in the laboratory, i.e., no brain imaging.

Approach-avoidance conflict

Intervention Type: BEHAVIORAL

Session 2 (Ca one week): Spider fear is probed by an approach-avoidance conflict task. Participants can receive varying small rewards for watching pictures of spiders, or avoid the spider pictures at the cost of not receiving a reward (neutral pictures are shown instead).

In vivo exposure

Intervention Type: BEHAVIORAL

Session 1 (Day 1): in vivo exposure. Participants receive repeated exposure to film clips of fear-provoking stimuli (spiders) and neutral stimuli (leaves) while undergoing brain imaging med fMRI.

Interventions

Imaginal exposure

Session 1 (Day 1): Participants receive repeated exposure to mental imagery of fear-provoking stimuli (spiders) and neutral stimuli (leaves) while undergoing brain imaging med fMRI.

Intervention Type: BEHAVIORAL

Exposure

Session 2 (Ca one week): Participants receive both imaginal and in vivo exposure to fear-provoking stimuli and neutral stimuli (both arms are exposed to both video clips (in vivo exposure) and mental imagery (imaginal exposure). Session 2 is conducted in the laboratory, i.e., no brain imaging.

Intervention Type: BEHAVIORAL

Approach-avoidance conflict

Session 2 (Ca one week): Spider fear is probed by an approach-avoidance conflict task. Participants can receive varying small rewards for watching pictures of spiders, or avoid the spider pictures at the cost of not receiving a reward (neutral pictures are shown instead).

Intervention Type: BEHAVIORAL

In vivo exposure

Session 1 (Day 1): in vivo exposure. Participants receive repeated exposure to film clips of fear-provoking stimuli (spiders) and neutral stimuli (leaves) while undergoing brain imaging med fMRI.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Willing and able to provide informed consent and complete study procedures
• Fear of spiders

Exclusion Criteria

• Current psychiatric disorder other than spider phobia
• Current use of psychotropic medication
• Current neurological conditions
• MRI-contraindications (i.e metal implants in skull)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Uppsala University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Thomas Ågren, PhD

Role: PRINCIPAL_INVESTIGATOR

Uppsala University

Locations

The Swedish 7T facility

Lund, , Sweden

Countries

Sweden

References

Hoppe JM, Holmes EA, Agren T. Exploring the neural basis of fear produced by mental imagery: imaginal exposure in individuals fearful of spiders. Philos Trans R Soc Lond B Biol Sci. 2021 Feb;376(1817):20190690. doi: 10.1098/rstb.2019.0690. Epub 2020 Dec 14.

Reference Type: RESULT

PMID: 33308073 (View on PubMed)

Other Identifiers

2020-06930a

Identifier Type: -

Identifier Source: org_study_id