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Psychophysiology of Delayed Extinction and Reconsolidation in Humans
The aim of this project is to create fear conditioning paradigm within which the relative strengths of various novel pharmacological and behavioral interventions can be tested. These interventions are intended to reduce the fearfulness associated with fear conditioning by blocking a memory process known as reconsolidation. In fear conditioning, a "conditioned" stimulus (CS) is paired with an aversive "unconditioned" stimulus (US) such as an electric shock, until presentation of the CS alone comes to elicit a fear conditioned response (CR). The investigators hypothesize that by using a more highly prepared CS (i.e. video of spiders); more sensitive subjects (individuals with stronger acquired CRs); and additional experimental probes for the presence of the latent CR, the investigators may develop a normal human paradigm that is not plagued by previously observed floor effects (i.e. intervention is 100% effective), within which both the established techniques of propranolol and delayed extinction will produce significant, but only partial, CR reduction. This would leave room to test and compare potentially more powerful candidate reconsolidation-blocking or memory-updating interventions. To achieve these aims, subjects will undergo a four-day fear conditioning and delayed extinction protocol. Skin conductance response data will be gathered across the different phases of the experiment.
Details
| Lead sponsor | Massachusetts General Hospital |
|---|---|
| Phase | Phase 4 |
| Status | COMPLETED |
| Enrolment | 186 |
| Start date | 2010-11 |
| Completion | 2015-01 |
Conditions
- Posttraumatic Stress Disorder
- Anxiety Disorder
Interventions
- Propranolol
- Reactivation
- Mifepristone
- Intranasal oxytocin
Primary outcomes
- Change From Baseline Skin Conductance Response — 48hrs
Skin conductance response (SCR) is the change in skin conductance level in response to a stimulus. We compared the SCR to a non-treated conditioned stimulus (CS+N) with the SCR to a treated conditioned stimulus (CS+R) by creating a difference score (CS+R - CS+N) for the day 3 data. Day 3 is 48 hours after the fear-conditioning procedure and serves as the primary measure of whether the treatment had an effect. SCR was measured in microSiemens; the SCR difference score reflects a change in microSiemens.
Countries
United States