Archival Report| Volume 73, ISSUE 11, P1071-1077, June 01, 2013

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Rapid Remission of Conditioned Fear Expression with Extinction Training Paired with Vagus Nerve Stimulation

Published:December 14, 2012DOI:


      Fearful experiences can produce long-lasting and debilitating memories. Extinction of conditioned fear requires consolidation of new memories that compete with fearful associations. In human subjects, as well as rats, posttraining stimulation of the vagus nerve enhances memory consolidation. Subjects with posttraumatic stress disorder show impaired extinction of conditioned fear. The objective of this study was to determine whether vagus nerve stimulation (VNS) can enhance the consolidation of extinction of conditioned fear.


      Male Sprague-Dawley rats were trained on an auditory fear conditioning task followed by 1 to 10 days of extinction training. Treatment with vagus nerve or sham stimulation was administered concurrently with exposure to the fear conditioned stimulus. Another group was given VNS and extinction training but the VNS was not paired with exposure to conditioned cues. Retention of fear conditioning was tested 24 hours after each treatment.


      Vagus nerve stimulation paired with exposure to conditioned cues enhanced the extinction of conditioned fear. After a single extinction trial, rats given VNS stimulation demonstrated a significantly lower level of freezing, compared with that of sham control rats. When extinction trials were extended to 10 days, paired VNS accelerated extinction of the conditioned response.


      Extinction paired with VNS is more rapid than extinction paired with sham stimulation. As it is currently approved by the Federal Food and Drug Administration for depression and seizure prevention, VNS is a readily available and promising adjunct to exposure therapy for the treatment of severe anxiety disorders.

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      Linked Article

      • Fear and Anxiety Take a Double Hit From Vagal Nerve Stimulation
        Biological PsychiatryVol. 73Issue 11
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          At the forefront of translational research to combat anxiety disorders is the idea of developing neuroscience-based adjuncts to traditional exposure-based treatment such as cognitive/behavioral therapy. The core concept of exposure therapy is Pavlovian extinction, in which an anxiety-triggering stimulus is repeatedly presented so that that the patient learns that the stimulus predicts no negative consequences. This new association acts to inhibit the anxiety normally provoked by the stimulus. On its own, such exposure is quite effective, but it has some limitations.
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