Forgetfulness seems like a part of getting older, but what if lapses in memory are just a symptom of a larger problem? A recent study suggests that significant amounts of stress and anxiety can be the cause of short-term memory loss in aging adults. According to findings published in the Journal of Neuroscience this month, researchers from the University of Iowa observed that high levels of the stress hormone, cortisol, can affect areas of the brain linked to memory.
Increases in cortisol keep us alert to changes and are crucial for survival. Extended, abnormal spikes in stress hormones, however, are known to cause problems with digestion, weight gain, and high blood pressure. With these negative consequences in mind, researchers found that there are even more issues related to large amounts of stress and anxiety.
The Maze Experiment
Researchers collected 21 month-old rats, the equivalent to 65 year-old humans, and 4-month-old rats, the equivalent to 20 year-old humans, and tested their natural stress hormone levels. They placed both groups of rodents in a maze that tested short-term memory. After placing each rat in the maze two times, their memories were tested based on how easily they found their way through the second run.
The study observed that, 58% of the time, older rats with higher levels of cortisol navigated their second time through the maze without choosing a wrong direction. Compare that with rats of the same age with low levels of stress who were found to move seamlessly throughout their second run 80% of the time.
After examining tissue samples of the rats' prefrontal cortexes, they found that rats who performed poorly exhibited smaller and fewer brain synapses, indicating memory loss. Regardless of age, the study concluded that rats with low stress levels performed better than rats with high amounts of cortisol.
Can Effects of Stress be Prevented?
While these observations link stress to memory loss, the effects may be prevented or slowed by treatments that decrease cortisol levels, suggests Jason Radley, assistant professor in psychology at University of Iowa and participating author of the study. In a lot of ways, this research helps memory loss in old age by pinpointing a major potential cause, which, in turn, makes huge strides towards discovering treatment options. According to Medical News Today, Radley and his team are excited that such a possibility is suggested based upon their findings.
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Rachel M. Anderson, Andrew K. Birnie, Norah K. Koblesky, Sara A. Romig-Martin, and Jason J. Radley. Adrenocortical Status Predicts the Degree of Age-Related Deficits in Prefrontal Structural Plasticity and Working Memory. The Journal of Neuroscience, 2014. DOI: 10.1523/JNEUROSCI.1385-14.2014
Date of original publication: June 20, 2014
Updated: April 21, 2017