Fear, Anxiety & PTSD: Neural Mechanisms Enhanced Through Fear-Leaning

Fear, Anxiety & PTSD: Neural Mechanisms Enhanced Through Fear-Leaning

            According to the National Center for Post-Traumatic Stress Disorder (PTSD), 7-8 out of every 100 people will have PTSD at some point in their lives. On October 22^nd 2019, Dr. Michael Fanselow, a distinguished professor and researcher at the University of California, Los Angeles, presented on his continuing research over the “Neurobehavioral perspectives on the distinction between fear and anxiety” (2015) and “Induction and Expression of Fear Sensitization Caused by Acute Traumatic Stress” (2016), wherein he explores what happens in a single traumatic experience that causes lifelong symptoms characterizing PTSD. Dr. Fanselow reported that 10-20% of individuals exposed to traumatic events would go on to develop symptoms of PTSD. Some important symptoms of PTSD include fear and avoidance of things associated with an event, persistence of this fear for at least 30 after the event has taken place, high rates of symptoms presenting along with other anxiety disorders and/or substance abuse, increased propensity acquire new phobias, resistance to exposure and extinction therapy, increased arousal, and exaggerated response to startling stimuli.

            Fear is generally thought of in an associative way, and the quintessential model of this type of fear learning is Pavlovian conditioning. Classic Pavlovian fear conditioning is characterized by cues presented at the time of trauma provoking fear memories and responses. Dr. Fanselow emphasized that the main focus of current biobehavioral research is to treat PTSD with extinction and exposure therapy. However, as previously stated, a major component of PTSD is that individuals become more resistant to this kind of therapy. Dr. Fanselow’s research takes on a new approach to possible treatments of PTSD by considering how a non-associative model called stress-enhanced fear learning (SEFL). This model is not bound by the cues that are specifically associated with the traumatic event, advancing the hypothesis that many symptoms of PTSD are derived from a form of sensitization rather than the context of the trauma.

By evaluating new neurobiological mechanisms associated with more sensitized, or heightened, behavioral responses, Dr. Fanselow and colleagues suggest that targeting certain neural components of this fear response pathway in order to better treat PTSD. Given the results of his study, Dr. Fanselow suggests blocking a steroid hormone glucocorticoid receptors in the brain’s fear center, or amygdala, would be effective in preventing the negative effects of stress-enhanced fear learning.

            An article published by Neuroscience News entitled “PTSD has strong genetic component like other psychiatric disorders” explores other biological mechanisms explaining persisting PTSD symptoms. This article presents a collaborative study done among scientists from the University of California San Diego School of Medicine, the Psychiatric Genomics Consortium’s PTSD working group, and a non-profit organization called Cohen Veterans Bioscience. Researchers used these global collaborations to recruit thousands of participants suffering from PTSD as well as a control group from a variety of backgrounds and a wide range of neuro-diversity. The long-term goal that researchers hoped to achieve was to "develop tools that might help clinicians predict who is at greatest risk for PTSD and personalize treatment approaches." The study assessed the genomes, in an approach referred to as a genome-wide association study (GWAS), of these participants and found that there were consistent DNA markers associated with being at higher risk for developing PTSD.

            The findings of this study suggest that there may be a way to assess individuals who are at high risk for developing PTSD and provide them with proactive treatments, such as encouraging therapy at an early age so as to lower the risk of developing PTSD if they are faced with a traumatic event.

            Both in the study showing PTSD to be linked to genetics and Dr. Fanselow’s research, we see how important it is to explore the mechanisms of PTSD in different ways in order to provide the best treatment to those who suffer the symptoms. Although there is much work to be done in order to truly understand the neural and biological basis of PTSD, these studies are important gateways into more individualized treatment from an illness that so many people suffer from in their lifetimes.

Dr Fanselow’s Research:

Perusini, J.N., Meyer, E.M., Long, V.A., Rau, V., Nocera N., Avershal, J., Maksymetz, J., Spigelman, I., & Fanselow, M.S. (2016) Induction and Expression of Fear Sensitization Caused by Acure Traumatic Stress. Neuropsychopharmacology, 41, 45-57. PMC4677128

Perusini, J.N., & Fanselow, M.S. (2015) Neurobehavioral perspectives on the distinction between fear and anxiety. Learning and Memory, 22, 417-425. PMC4561408

PTSD Article:

Buschman, H. (2019, October 9) PTSD has strong genetic component like other psychiatric disorders. Neuroscience News, Retrieved from https://neurosciencenews.com/ptsd-genetics-15048/