Thursday, November 3, 2011

Memory Loss Accociated with Age

Recently a study has been done that relates older age memory loss to stress hormone receptors in the brain. The stress hormone, cortisol, affects two receptors in the brain that cause an increase in forgetfulness as people age. One receptor activated by low levels of cortisol actually helped with memory. If the stress hormone got too high though, it would affect a second receptor which would cause memory loss. This study was done in mice that were observed traveling through a maze. Mice with high levels of the stress hormone were not able to travel through the maze as well as the mice with less of the hormone. When the receptor was blocked, the mice were able to remember their way through the maze again. "While we know that stress hormones affect memory, this research explains how the receptors they engage with can switch good memory to poorly-functioning memory in old age," according to Dr Joyce Yau of the University's Centre of Cardiovascular Science. This information led to the conclusion that too much stress over a long period of time can affect the memory of older individuals. Lowering the stress hormone level can improve memory by not activating the receptors in the brain that cause memory loss. Researchers are currently looking for a way to block the enzyme that produces the stress hormone in the cells. Blocking this enzyme could result in better memory because the stress hormones would not be released at high levels. If a drug came out that could prevent high levels of cortisol then it could slow the normal decline in memory associated with aging and even help the very elderly improve in their memory.

Older individuals also have a higher chance of memory loss if they have Metabolic Syndrome. Metabolic Syndrome is when a person has three or more of the following risk factors: hypertension, excessive belly fat, higher than normal triglycerides, high blood sugar, and low HDL cholesterol. A study of 7,087 people over the age of 65 was done to determine if any of the individuals had Metabolic Syndrome. A total of 16% had Metabolic Syndrome and all individuals were given a series of memory and cognitive function tests two and four years later. “Researchers found that people who had metabolic syndrome were 20 percent more likely to have cognitive decline on the memory test than those who did not have metabolic syndrome. Those with metabolic syndrome also were 13 percent more likely to have cognitive decline on the visual working memory test compared to those who did not have the syndrome.” These tests show that people with Metabolic Syndrome are more likely to experience memory loss. If individuals take care of themselves and reduce their risk factors, then they have a better chance of having a better memory for a longer period of time.


  1. I thought you had good substantual information on the effects to this study. Also I loved the picture of the elderly! But I wondered if your information led you to a percentage of how many people are effected by memory loss today?

  2. Thanks! Approximately 24 million people worldwide have dementia of which the majority (~60%) is due to Alzheimer's.

    Here is the website I got this information from.

  3. Your post is a nice example of the different jobs that proteins can do. In your first research story they are both receptors for stress hormones and the enzymes that make or release those hormones. And apparently some of these proteins are being targeted in the design of new drugs.

  4. I liked how you talked about cortisol levels and its effect on memory, and then used that information to lead into Metabolic Syndrome.

    I was wondering if you found a research study to support:
    "One receptor activated by low levels of cortisol actually helped with memory." Just was interested in finding more information on how exactly the first receptor is activated and more about its positive effect on memory.

  5. The first article I have linked at the top of the blog goes into more detail, but here is what I found. "The study, by the University of Edinburgh, found that one receptor was activated by low levels of cortisol, which helped memory. However, once levels of this stress hormone were too high they spilled over onto a second receptor. This activates brain processes that contribute to memory impairment." So low levels of cortisol help with memory but when they get too high it effects memory in a negative way.

  6. This was a very interesting post. I did not know stress lead to memory loss. You article will make me think more about my study and life habits when going into finals and the rest of my life