Summary: Researchers find that changes in the brain’s salience network occur when a person experiences trauma.
Source: University of Rochester
Exposure to trauma can be life changing – and researchers are learning more about how traumatic events can physically alter our brains. But these changes don’t happen because of physical injuries; on the contrary, the brain seems to rewire itself after these experiences.
Understanding the mechanisms involved in these changes and how the brain learns about an environment and predicts threats and security is one of the goals 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’re learning more about how people exposed to trauma learn to distinguish between what’s safe and what’s not. Their brains give us insight into what could go wrong in specific mechanisms that are impacted by exposure to trauma, especially when emotion is involved,” said Suarez-Jimenez, who started this work as as a postdoctoral fellow in the laboratory of Yuval Neria. , Ph.D., professor at Columbia University Irving Medical Center.
Their research, recently published in Communications Biologyidentified changes in the salience network – a brain mechanism 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 participants’ brains as they looked at circles of different sizes – a single size was associated with a small shock (or threat). Along with the changes in the salience network, the researchers found another difference, this one within the resilient trauma-exposed group.
They found that the brains of people exposed to trauma without psychopathology compensated for changes in their brain processes by engaging the executive control network, one of the brain’s dominant networks.
“Knowing what to look for in the brain when someone is exposed to trauma could significantly advance treatments,” said Suarez-Jimenez, co-first author with Xi Zhu, Ph.D., assistant professor of clinical neurobiology at Columbia. paper. “In this case, we know where a change is happening in the brain and how some people can circumvent that change. It is a marker of resilience.
Added the emotion element
The possibility of a threat can change how someone exposed to trauma responds. Researchers found this to be the case in people with post-traumatic stress disorder (PTSD), as described in a recent study in Depression and anxiety. Suarez-Jimenez, fellow co-authors and lead author Neria found that patients with PTSD can perform the same task as someone without exposure to trauma when no emotion is involved.
However, when the emotion invoked by a threat was added to a similar task, people with PTSD had more difficulty distinguishing the differences.
The team used the same methods as the other experiment – different circle sizes with one size tied to a threat in the form of a shock. Using fMRI, researchers observed that 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 emotion-related area) and the default mode network (an area of the brain that activates when someone isn’t focused on the outside world. ). These results reflect the inability of a person with PTSD to effectively distinguish the differences between the circles.
“This tells us that patients with PTSD only have problems discriminating when there is an emotional component. In this case, aversive; we have yet to confirm if this is true for other emotions like sadness, disgust , happiness, etc,” Suarez-Jimenez said. “So it could be that in the real world, emotions are overloading their cognitive ability to distinguish between safety, danger, or reward. the danger.
“Taken together, the results of the two papers, from a…study aimed at uncovering the neural and behavioral mechanisms of trauma, PTSD and resilience, help to expand our knowledge of the effect of trauma on the brain. “said Neria, the IP lead on this study.
“PTSD is driven by remarkable dysfunction in brain areas vital for processing and responding to fear. My lab at Columbia and Dr. Suarez-Jimenez’s lab in Rochester are committed to advancing neurobiological research that will serve to to develop new and better treatments that can effectively target aberrant fear circuits.
Suarez-Jimenez will continue to explore brain mechanisms and the different emotions associated with them using more real-life situations using virtual reality in his lab. He wants to understand if these mechanisms and changes are specific to a threat and if they extend to context-related processes.
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About this trauma and neuroscience research news
Author: Press office
Source: University of Rochester
Contact: Press Office – University of Rochester
Image: Image is in public domain
Original research: Free access.
“Sequential fear generalization and network connectivity in trauma-exposed humans with and without psychopathology” by Xi Zhu et al. Communications Biology
Summary
Sequential fear generalization and network connectivity in trauma-exposed humans with and without psychopathology
While impaired fear generalization is known to underlie a wide range of psychopathologies, the extent to which exposure to trauma by itself leads to impaired fear generalization and its neural abnormalities remains to be investigated. Similarly, the neural function of intact fear generalization in individuals who have experienced trauma and have not developed significant psychopathology remains to be characterized.
Here, we use a generalization fMRI task and a network connectivity approach to clarify putative behavioral and neural markers of trauma and resilience. The generalization task allows for longitudinal assessments of threat discrimination learning.
Participants exposed to trauma (TE; NOT= 62), compared to healthy controls (HC; NOT= 26), show lower activity reduction in the salience network (SN) and right executive control network (RECN) across both sequential generalization steps, and worse discrimination learning in the measured SN by linear deviation scores (LDS).
Comparison of healthy, resilient, and trauma-exposed control (TEHC) participants; NOT= 31), trauma-exposed individuals with psychopathology (TEPG; NOT= 31), and HC, reveals a signature of resilience of network connectivity differences in the RECN during generalization learning measured by LDS.
These findings may indicate a trauma-exposed phenotype that has the potential to advance the development of innovative treatments by targeting and engaging specific neural dysfunction in trauma-exposed individuals, in different psychopathologies.
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