Posts Tagged ‘cognitive processing therapy’

The Neuroscience of Extinction

March 12, 2020

This post is based on a book, Resilience: The Science of Mastering Life’s Greatest on Challenges by by Steven Southwick and Dennis Charney. The process of overcoming a learned fear is called extinction. It involves the brain structures that were discussed in earlier posts on this book (amygdala, prefrontal cortex (PFC), and hippocampus). To extinguished a fear-conditioned memory, a person must be exposed to the fear-inducing stimulus in a safe environment, and the exposure needs to last long enough for the brain to form a new memory. The new memory conveys that the fear-conditioned stimulus is no longer dangerous in the present environment. Brain imaging suggests that extinction may involve a strengthening of the capacity of the PFC to inhibit amygdala-based fear responses.

One therapy, flooding or direct exposure, requires prolonged exposure to the memory of the traumatic event. The therapy consists of “extended exposure to moderate or strong fear-producing cues. In their imagination, patients are asked to recount the traumatic experience with eyes closed and in as much detail as possible, describing sights, sounds, smells, and sensations, as well as what they were thinking and feeling. These sessions are recorded, and the client listens to the recording repeatedly on subsequent days. In the in-vivo component, clients “gradually confront safe situations that evoke moderate levels of anxiety and then follow up with confrontation of more fearful situations.

As extinction involves new learning, and the protein molecule known as the NMDA receptor is critical to learning, Barbara Rothbaum and colleagues gave the NMDA receptor partial agonist D-closerine (DCS) with exposure therapy. DCS is a drug that activates the NMDA receptor which then enhances learning of the new memory. This study supported the conclusion that these treatments fostered the desired extinction. Unfortunately, this type of treatment has not always resulted in success, but the prospect of augmenting extinction-based therapies, like prolonged exposure, with medications that affect learning is positive.

Cognitive processing therapy (CPT) also involves confronting fear. It uses the Socratic method of teaching, in which the teacher poses questions and the student, by answering them, learns new ways of understanding. CPT focuses on emotions such as anger, humiliation, shame, guilt, and sadness, which trauma survivors often experience in addition to fear and anxiety. It is not uncommon for trauma victims to believe that they could have done something to prevent the traumatic or acted more heroically to minimize harm, even if in reality such actions would have been impossible. They tend to blame themselves and to imagine that others blame them as well. For example, a crime victim may have unrealistic beliefs such as, “I shouldn’t have gone to the ATM that night.” A therapist using CPT asks questions aimed at helping the patient to arrive at the more realistic conclusion that he or she could not have predicted that a robber would chose that particular ATM on that particular evening, and that the fault lies with the thief, not with the victim.

One does not necessarily have to undergo therapy to transform or extinguish a fearful memory. It takes courage, but one can try to confront the fearful event and through repetitions extinguish the fear. So the best response to falling off a horse might be to get back on.