Fireworks on nights other than the Fourth of July or New Year’s Eve equals fun and celebration for most people, especially children. But for veterans with Post Traumatic Stress Disorder (PTSD), the shock of noise and light may trigger a deeply learned expectation of danger.
Virginia Tech scientists have found that people with PTSD have an increased learning response to surprising events, such as the whizz and pop of fireworks. While most everyone reacts to surprise, people with PTSD tend to pay even more attention to the unexpected. The study was published in January 2018.
“Disproportionate reactions to unexpected stimuli in the environment are a core symptom of PTSD,” said Pearl Chiu, an associate professor with dual appointments at the Virginia Tech Carilion Research Institute (VTCRI) and the Department of Psychology, and who served as lead author on the study. “These results point to a specific disruption in learning that helps to explain why these reactions occur.”
Joining Chiu on the study were, among others, Vanessa Brown, first author on the paper and a graduate student in the Department of Psychology, and Brooks King-Casas, also an associate professor at the VTCRI and associate professor of psychology. The team used functional MRI to scan the brains of 74 veterans, all of whom had experienced trauma while serving in Afghanistan or Iraq.
Some of the study participants were diagnosed with PTSD, while others were not. In the functional MRI, participants played a gambling game, in which they learned to associate certain choices with monetary gains or losses.
The researchers found that people with PTSD had significantly more activity in the parts of their brains associated with how much attention they paid to surprising events when the learning task threw an unexpected curve ball their way. “Fireworks unexpectedly going off after a person has exchanged fire in the field can trigger an over-estimation of danger,” King-Casas said. “Particularly for individuals with PTSD, unexpected surprising events — noise or otherwise — could be a matter of life or death.”
Both the behavioral and neural findings show that people with PTSD pay more attention to surprise while learning, added Brown. “This disrupted learning increases with more severe PTSD,” Brown said. “Now that we understand how attention to surprise plays a role in PTSD, we may be able to refine our assessment tools or develop new interventions that target specific learning disruptions in people with PTSD or other psychiatric disorders.”