Fear and Anxiety Take a Double Hit From Vagal Nerve Stimulation

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. After exposure therapy, fear of the extinguished stimulus may return because of a stressful experience, a long passage of time since encountering the stimulus, or confronting the fear-provoking stimulus in a novel environment ( ). Additionally in some anxiety disorders, notably posttraumatic stress disorder, extinction learning itself is compromised ( ). The idea of neuroscience-based adjuncts given during exposure treatment is to overcome this limitation by either strengthening the extinction learning itself or changing its nature. An example of the strengthening strategy is the use of d-cycloserine (DCS) to facilitate the N-methyl-D-aspartate–mediated plasticity that normally mediates memory formation ( ). To change the nature of extinction, researchers have administered extinction training during periods when the original fear memory lacks stability because it was very recently encoded or reactivated ( , ).