Imaginal exposure is a widely used and effective psychological treatment technique in which patients are exposed to fearful stimuli and situations using mental imagery. This study examines imaginal extinction, an experimental analogue of imaginal exposure that allows the study of this treatment technique under controlled circumstances. During imaginal extinction, conditioned fear is diminished through repeated exposure to mental imagery of the feared (conditioned) stimulus. The neural underpinnings of imaginal extinction is not known, and hence, this study examines neural activations during imaginal extinction using psychophysiology and brain imaging.

In this study, participants undergo threat conditioning to two pictures (CS+, CS-) in order to acquire a conditioned threat response. After this, the conditioned threat response is diminished through imaginal extinction (i.e extinction to the mental imagery of CS+ and CS-). Functional magnetic resonance imaging (7T) is used to measure neural activations during threat conditioning and imaginal extinction. Skin conductance is used to measure arousal response. Subjective fear and mental imagery vividness ratings will also be collected. In this way, this study aims to characterize the neural underpinnings of imaginal extinction.

Note that this study employs participants fearful of spiders. This is because data collection is shared with a related study (ClinicalTrials.gov ID 2020-06930a).

Inclusion Criteria:

• Willing and able to provide informed consent and complete study procedures
• Fear of spiders (due to data collection together with ID 2020-06930a)

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).

We plan to share anonymous behavioural and brain imaging data, training material, Statistical Analysis plan, and informed consent form on the project site on Open Science Framework (https://osf.io/s54dz/).

Data will be available from completion of analysis and publication, and onwards.

Anonymous behavioural and brain imaging data, training material, and Statistical Analysis plan will be made public on the project site on Open Science Framework (https://osf.io/s54dz/)