Saturday, July 26, 2014

Stress Hormones and Memory

Have you ever experienced a traumatic event and remember or recall the event for years and years afterward? Why is that? Scientists are digging further to try to understand how traumatic events trigger key memory hormones especially in women. When you experience a traumatic event your body releases two stress hormones. One of those hormones is norepinephrine and the other is cortisol. To better understand how these stress hormones work together lets briefly explain their purpose.

Norepinephrine is a hormone very similar to adrenaline which is released by the adrenal glands. This is your arousal hormone and as we all know when under stress a person tends to be more responsive. Norepinephrine acts as an active site to trigger blood flow and deliver it to necessary parts of the body to help reduce stress. Norepinephrine can also be released from the brain, when this happens its main function is to act as a neurotransmitter which helps enhance memory.

Cortisol is a steroid hormone also released by the adrenal glands. Cortisol has a powerful strengthening memory mechanism just like norepinephrine. Cortisol helps maintain blood pressure. Under stressful situations, cortisol is released continuously and an over load of cortisol can lead to health issues. Too much cortisol can suppress the immune system and contribute to obesity among other things. The release of cortisol depends on the activation of the hormone norepinephrine in order to be successful in the strengthening memory mechanism.

During my research I found an interesting experiment that was documented by Sabrina Segal who is assistant research professor at the Institute for Interdisciplinary Salivary Bioscience Research at Arizona State University and her colleagues at the University of California. The study included 39 women who viewed 144 graphic images that were designed to trigger reactions that range from neutral to emotional. Before the image test, participants were given either a hydrocortisone shot or a harmless pill to help stimulate stress. The women were asked to report their feelings during the test and provide a saliva sample after the exam. One week later, participants were called again for a recall test. The results were not surprising. When you experience a traumatic event, both cortisol and norepinephrine need to be released which together trigger the memory enhancing mechanism and the traumatic event is never forgotten.

Another thing the study revealed was that if you can lower the norepinephrine levels immediately following a traumatic event; even if cortisol levels are present you can reduce or prevent the memory enhancing mechanism from occurring.

Just based on this one study, much more research is needed to explore the relationships between cortisol and norepinephrine depending on whether you are male or female. Although one website did say that women are twice as likely to develop disorders from stress and trauma that effect memory. One such disorder is Posttraumatic Stress Disorder. Understanding how the brain reacts to a traumatic event and the memories built from that event could help develop therapeutics that can help people suffering such a disorder.


1 comment:

  1. I have heard about this but I never really looked into it and I liked reading your article and finding out more about some of the studies that have been done and learning more about it. I think that it is crazy that we can forget many things or only remember parts of different memories, but a traumatic event is never forgotten. I would be interested in finding out if there is more of a difference between men and woman and how different events affect different people.