Clinical

Brain circuitry for both positive and negative ‘valence’ affected by trauma

Post-traumatic stress disorder (PTSD) is a common side effect for many individuals after a stressful event (PTSD). Hyperarousal and avoidance of dangerous or possibly harmful actions are hallmarks of post-traumatic stress disorder (PTSD).

According to research, the brain contains unique circuitries for mediating rewarding and unpleasant activities. In the past, researchers believed that post-traumatic stress disorder (PTSD) was caused by an overactive negative valence system. However, a recent study shows that people with PTSD also show a deficit in activation of positive valence processing soon after the trauma, suggesting that it plays a role in resilience to PTSD.

Biological Psychiatry: Cognitive Neuroscience and Neuroimaging by Elsevier publishes the study.

It was discovered that 171 patients who had been treated for trauma in a hospital emergency room (such as a vehicle accident) were suffering from symptoms of post-traumatic stress disorder (PTSD) within two weeks of the incident. After a month, trauma survivors completed further testing in the lab with a certified clinical interviewer and functional magnetic resonance imaging (fMRI) scans on their brains (fMRI). Identical evaluations were carried out six months and fourteen months after the incident.

Researchers used functional magnetic resonance imaging (fMRI) to study the effects of playing a competitive electronic gambling game on participants’ risk sensitivity, rewards, and punishment. As expected, those with more severe PTSD symptoms made less hazardous choices in the game and their fMRI scans revealed increased activity in the amygdala, a brain area involved with fear processing and a crucial component of the negative valence system. At one month, ventral striatum activity in the mesolimbic brain, which processes positive valence such as rewards, was found to be lower, which predicted more severe PTSD symptoms 14 months later.

Researchers say the discovery “provides insights on roles played by both positive and negative valence processing systems in early development of post-traumatic psychopathology,” according to Dr. BenZion. Many studies have focused only on the hyper-active negative valence system (e.g., increased fear and threat responses), but our findings suggest that the hypo-active positive system (e.g., less neural activation towards rewards) may play an important role in the development of PTSD and point to its role in resilience against trauma as well as adaptive healing after trauma.””

“This study gives fresh insights into the basic alterations in brain activity that follow traumatic events and underpin the development of PTSD,” stated Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. The research tells us that these alterations go beyond dysregulated threat processing and involve reward and motivation-related brain circuits that are likely to explain mood and motivated behavior abnormalities in PTSD.”

“New therapeutic approaches should address both the positive and negative valence systems, as these two are intrinsically linked and both affect the symptom development after experiencing traumatic stress,” Professor Hendler said of the study’s potential implications for therapeutic strategies to treat stress and anxiety disorders.

A more individualized approach to mental health therapy might be guided by unique impairments in each valence system, which could be linked to specific symptoms of post-traumatic stress disorder (PTSD).

Source: Ziv Ben-Zion, Ofir Shany, Roee Admon, Nimrod Jackob Keynan, Netanell Avisdris, Shira Reznik Balter, Arieh Y. Shalev, Israel Liberzon, Talma Hendler. Neural Responsivity to Reward versus Punishment Shortly after Trauma Predicts Long-term Development of Post-Traumatic Stress SymptomsBiological Psychiatry: Cognitive Neuroscience and Neuroimaging, 2021; DOI: 10.1016/j.bpsc.2021.09.001

Categories: Clinical