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 a 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 development 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.
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