Did you ever wonder how some people can come out of really traumatic experiences, such as war, and return to a fairly normal life while others develop post-traumatic stress disorder (PTSD) or other problems related to stress, cognitive function and memory loss?
A study published in Proceedings of the National Academy of Sciences reports the first evidence that a person’s sensitivity to acute stress is determined by variations in the gene encoding the α2b-adrenoreceptor (ADRA2B). Does that mean the some people can handle stress and stressful situations better than others because of a hormone? It appears that way.
The research, led by scientists at the University of Basel in Switzerland, have found that stress hormones affect the way memories are stores and retrieved, and that basic changes in the brain from exposure to stress varies per individual. Most noticeable are the responses from the stress hormones, known as cortisol, that are released by the hypothalamus.
Our brains respond to immediate threats. This is known as the “fight or flight” response. In people who are most vulnerable to stress, heightened response continues long after the external stress ends, which leads to stress-related disorders such as PTSD.
Researchers, presenting at a meeting of the Federation of European Neuroscience Societies (FENS) in Amsterdam, suggest that a person’s gene expression profile may influence the difference between some people who are emotionally equipped to handle trauma, and those who develop PTSD and other stress disorders.
Researchers showed violent movie scenes to subjects and asked them to imagine they were actually in the scenario. MRI (Magnetic Resonance Imaging) scans recorded the information, focusing on the amygdale (brain’s stress center), where threat detection and emotional memories are stored. In previously published research, scientists found a variation in the ADRA2B receptor is responsible for creating and retaining memories that are emotionally arousing.
The findings indicated that those who possessed common variations of the ADRA2B receptor had more connectivity between the amygdale and other brain stress circuitry, and higher response to stress.
One interesting side-note of the research was that a lower level of cortisol in the blood was also present in these individuals, and when injected with cortisol some actually showed reduced traumatic memories. Cortisol is a hormone released by the adrenal gland in response to stress.
Although more research on this is needed to see if cortisol may be a treatment in stress disorders, like PTSD, research has proven that stress has a negative effect on memory and our ability to learn and retain information. If the hormone cortisol is not released as needed in some people, there could be a correlation between our hormones, our ability to assimilate and react to stressful situations, and our ability to memorize and improve our memory.
Sources:
Wikipedia: Cortisol – http://en.wikipedia.org/wiki/Cortisol
