Trauma can have a significant impact on the brain, leading to changes in brain structure and function. These changes can affect a person’s thoughts, emotions, and behaviors. One way that trauma can change the brain is by altering the levels of certain chemicals in the brain, such as neurotransmitters and hormones. For example, exposure to trauma has been associated with changes in the levels of serotonin, norepinephrine, and cortisol. These changes can affect a person’s mood, anxiety levels, and ability to regulate their emotions.
Trauma can also lead to structural changes in the brain, such as changes in the size or density of certain brain regions. For example, research has shown that people who have experienced trauma may have a smaller hippocampus, a brain region that is involved in memory and emotion regulation. It is important to note that the brain is a highly adaptable organ and it is possible for individuals to recover from the effects of trauma with the right support and treatment.
Researchers are learning more about how traumatic events affect our brains physically. Changes in a brain mechanism used for learning and survival have been discovered by neurologists to play a role in how someone responds to a threat following a traumatic experience. Another study discovered that another mechanism involved in emotion and memory is impacted, making it difficult for someone suffering from PTSD to distinguish between safety, danger, and reward. It overgeneralizes in the direction of danger. These findings have the potential to significantly advance future treatments.
We are learning more about how people exposed to trauma learn to distinguish between what is safe and what is not. Their brain is giving us insight into what might be going awry in specific mechanisms that are impacted by trauma exposure, especially when emotion is involved.
Suarez-Jimenez
Trauma can have a life-changing impact, and researchers are learning more about how traumatic events can physically alter our brains. However, these changes do not appear to be the result of physical injury; rather, our brain appears to rewire itself as a result of these experiences. Understanding the mechanisms underlying these changes, as well as how the brain learns about its surroundings and predicts threats and safety, is a primary goal of the ZVR Lab at the Del Monte Institute for Neuroscience at the University of Rochester, led by assistant professor Benjamin Suarez- Jimenez, Ph.D.
“We are learning more about how people exposed to trauma learn to distinguish between what is safe and what is not. Their brain is giving us insight into what might be going awry in specific mechanisms that are impacted by trauma exposure, especially when emotion is involved,” said Suarez-Jimenez, who began this work as a post-doctoral fellow in the lab of Yuval Neria, Ph.D., professor at Columbia University Irving Medical Center.
Their research, recently published in Communications Biology, identified changes in the salience network – a mechanism in the brain used for learning and survival – in people exposed to trauma (with and without psychopathologies, including PTSD, depression, and anxiety). Using fMRI, the researchers recorded activity in the brains of participants as they looked at different-sized circles – only one size was associated with a small shock (or threat). Along with the changes in the salience network, researchers found another difference – this one within the trauma-exposed resilient group. They found the brains of people exposed to trauma without psychopathologies were compensating for changes in their brain processes by engaging the executive control network – one of the dominate networks of the brain.
“Knowing what to look for in the brain when someone is exposed to trauma could significantly advance treatments,” said Suarez-Jimenez, a co-first author with Xi Zhu, Ph.D., Assistant Professor of Clinical Neurobiology at Columbia, of this paper. “In this case, we know where a change is happening in the brain and how some people can work around that change. It is a marker of resilience.”
Adding the element of emotion
The possibility of threat can change how someone exposed to trauma reacts – researchers found this is the case in people with post-traumatic stress disorder (PTSD), as described in a recent study in Depression & Anxiety. Suarez-Jimenez, his fellow co-authors, and senior author Neria found patients with PTSD can complete the same task as someone without exposure to trauma when no emotion is involved. However, when emotion invoked by a threat was added to a similar task, those with PTSD had more difficulty distinguishing between the differences.
The team used the same methods as the other experiment – different circle sizes with one size linked to a threat in the form of a shock. Using fMRI, researchers observed people with PTSD had less signaling between the hippocampus – an area of the brain responsible for emotion and memory – and the salience network – a mechanism used for learning and survival. They also detected less signaling between the amygdala (another area linked to emotion) and the default mode network (an area of the brain that activates when someone is not focused on the outside world). These findings reflect a person with PTSD’s inability to effectively distinguish differences between the circles.
“This tells us that patients with PTSD have issues discriminating only when there is an emotional component. In this case, aversive; we still need to confirm if this is true for other emotions like sadness, disgust, happiness, etc.,” said Suarez-Jimenez. “So, it might be that in the real-world emotions overload their cognitive ability to discriminate between safety, danger, or reward. It overgeneralizes towards danger.”
“Taken together, findings from both papers, coming out of an NIMH-funded study aiming to uncover neural and behavioral mechanisms of trauma, PTSD, and resilience, help to extend our knowledge about the effect of trauma on the brain,” said Neria, lead PI on this study. “PTSD is driven by remarkable dysfunction in brain areas vital to fear processing and response. My lab at Columbia and the Dr. Suarez-Jimenez lab at Rochester are committed to advance neurobiological research that will serve the purpose of developing new and better treatments that can effectively target aberrant fear circuits.”
Suarez-Jimenez will continue exploring the brain mechanisms and the different emotions associated with them by using more real-life situations with the help of virtual reality in his lab. He wants to understand if these mechanisms and changes are specific to a threat and if they expand to context-related processes.
Additional authors include co-first authors John Keefe, Ph.D., of Albert Einstein College of Medicine and Xi Zhu, Ph.D., of Columbia University Irving Medical Center, Amit Lazarov, Ph.D., of Columbia University Irving Medical Center, Ariel Durosky of the University of Tulsa, Oklahoma, Sara Such of the University of Pennsylvania, Caroline Marohasy of the University of Washington, Seattle, and Shmuel Lissek of the University of Minnesota, Minneapolis. The research was supported by the National Institute of Mental Health.
