A team of scientists from UCLA has concluded a study in rats that suggests that trauma to the brain can lead to an increased susceptibility to post-traumatic stress disorder (PTSD). The study purports to be the first to establish a mechanical link between traumatic brain injuries (TBIs) and PTSD. The complete results can be found in the journal Biological Psychology.
Looking at the prevalence of TBI and PTSD in returning servicemen and -women, the team noticed a correlation between the two. They set out to prove the link was not purely emotional. It had been assumed that events that cause TBI are inherently scary, and so are simply more likely to develop into PTSD.
The scientists used "fear conditioning" to train rats to be frightened two days after experienced a concussion. By separating the mechanical injury (the concussive event) from the emotional experience of fear, they hoped to prove a causal link. They found that rats who received the TBI were significantly more likely to acquire an inappropriately strong fear from the later conditioning than rats who experienced no TBI and were exposed to the fear conditioning alone.
Further testing of tissue from the rats' amygdalas showed increased numbers of receptors involved in learning. These findings suggest that TBIs leave the brains of people (and rats) in a more excitable state, and more prone to acquire "potent fear". The team hopes that their work will help clinicians better diagnose individuals with PTSD based on past experience with potentially brain-damaging injuries.
Source: University of California, Los Angeles
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