Study reveals how brain injury can lead to post-traumatic stress disorder

Post-traumatic stress disorder in U.S. military members frequently follows a concussion-like brain injury. Until now, it has been unclear why. A UCLA team of psychologists and neurologists reports that a traumatic brain injury causes changes in a brain region called the amygdala; and the brain processes fear differently after such an injury.“Is one causing the other, and how does that occur?” asked senior author Michael Fanselow, who holds the Staglin Family Chair in Psychology at UCLA and is the director of UCLA’s Staglin Music Festival Center for Brain and Behavioral Health. “We’re learning.”Two groups of rats were studied. Through surgery, a concussion-like brain injury was produced in 19 of the rats. Sixteen other rats — a control group — also had the surgery, but did not sustain a brain injury. All of the rats were then exposed to a low level of noise, followed by a series of moderate, brief foot shocks. The foot shocks were frightening to the rats, but not very painful, Fanselow said. Because the rats learne d to associate the noise with the shock, they became afraid of the noise.Rats tend to stand still when they experience fear. When they recall a frightening memory, they freeze. Their heart rate and blood pressure go up — and the stronger the memory, the more they freeze, Fanselow said. On the experiment’s third day, the researchers again exposed the rats to the same place where they had been shocked, but did not give them any additional shocks, a...
Source: UCLA Newsroom: Health Sciences - Category: Universities & Medical Training Source Type: news