Stress and Memory

In his book, Why Zebras Don't Get Ulcers, Dr. Robert Sapolsky discusses the various mechanisms by which stress induces illness in human beings.  Sapolsky, a professor of neurology and biological sciences at Stanford University, highlights the key differences in the stress responses between humans and their animal counterparts, ultimately relaying the message that we make ourselves sick.  

structure of glucocortiod

The section of Sapolsky's book that I was particularly interested in was Chapter 10, "Stress and Memory."  Here, he discusses the effect of the class of steroid hormones, glucocorticoids, on the brain.  In the healthy body, these steroid hormones play an important role in metabolic, immunological, developmental, and cognitive processes. At abnormally high levels, glucocorticoids disrupt a person's ability to store new memories.  Stress is among several possible causes for increased glucocorticoid levels.  Other possible causes for these abnormal levels are Cushing's syndrome and treatment with steroid anti-inflammatory compounds that contain synthetic glucocorticoids.

Perhaps the most interesting part of stress-induced memory disruption is the brain's ability to highlight emotionally traumatic memories, such as those experienced by an individual with PTSD.  While Sapolsky explains that most humans are vulnerable to the negative consequences of stress, I found it particularly intriguing to understand how stress in extreme proportions can have permanently damaging effects on the brain and health. 


(Also, there is a PBS called "This Emotional Life," featuring Dr. Sapolsky, that included a segment on PTSD. )