Is this mountain lion in a zoo, or your backyard? You’d respond differently to it depending on how your brain processes the context in which you’re encountering it.
What’s Really Going on in PTSD Brains? U-M Experts Suggest New Theory
In a Perspective article published this week in Neuron, a pair of University of Michigan Medical School professors – who have studied PTSD from many angles for many years – put forth the theory that people with PTSD appear to suffer from disrupted context processing. That’s a core brain function that allows people and animals to recognize that a particular stimulus may require different responses depending on the context in which it is encountered. It’s what allows us to call upon the “right” emotional or physical response to the current encounter.
A simple example, they write, is recognizing that a mountain lion seen in the zoo does not require a fear or “flight” response, while the same lion unexpectedly encountered in the backyard probably does.
For someone with PTSD, a stimulus associated with the trauma they previously experienced – such as a loud noise or a particular smell – triggers a fear response even when the context is very safe. That’s why they react even if the noise came from the front door being slammed, or the smell comes from dinner being accidentally burned on the stove.
“We hope to put some order to all the information that’s been gathered about PTSD from studies of human patients, and of animal models of the condition,” says Israel Liberzon, MD, a professor of psychiatry at U-M and a researcher at the VA Ann Arbor Healthcare System who also treats veterans with PTSD. “We hope to create a testable hypothesis, which isn’t as common in mental health research as it should be. If this hypothesis proves true, maybe we can unravel some of the underlying pathophysiological processes, and offer better treatments.”
Funding: This work was funded in part by the Department of Defense (W81XWH-13-1-0377) and the National Institute of Mental Health (MH075999 and MH093486).
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