Oxytocin facilitates the extinction of conditioned fear in humans

What Was Tested

This randomized controlled trial paper looks at Oxytocin.

Current neurocircuitry models of anxiety disorders posit a lack of inhibitory tone in the amygdala during acquisition of Pavlovian fear responses and deficient encoding of extinction responses in amygdala-medial prefrontal cortex circuits.

Competition between these two responses often results in a return of fear, limiting control over anxiety.

Who Took Part

The abstract describes 62 participants taking part.

By PubMed's age tags, the people studied were young adults and adults, men only.

To address the question whether oxytocin can strengthen Pavlovian extinction beyond its role in controlling social fear, the researchers conducted a functional magnetic resonance imaging experiment with 62 healthy male participants in a randomized, double-blind, parallel-group, placebo-controlled design.

How the Study Was Run

In design terms this was a randomized, double-blind, placebo-controlled and parallel-group study.

Random assignment meant chance, not the researchers, decided who got Oxytocin and who got the comparison, which limits bias.

Neither the participants nor the staff measuring them knew who was on Oxytocin, so expectations could not easily colour the readings.

Some participants received a placebo instead of Oxytocin, giving a reference point.

Groups ran in parallel: each of the participants stayed in one arm throughout.

Key among the endogenous inhibitors of amygdala activity in response to social fear signals is the hypothalamic peptide oxytocin.

What Was Measured

PubMed files the paper under topics including Amygdala, Conditioning, Classical, Fear, Galvanic Skin Response, Healthy Volunteers, Magnetic Resonance Imaging and Oxytocin.

The authors tagged it with the keywords Fear extinction, Psychophysiology, Skin conductance and fMRI.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Oxytocin in 62 participants.

The abstract goes on to report its results in about 4 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2015 (Biological psychiatry), a journal based in United States.

More context: the Oxytocin compound page, all human trials.