March 8, 2012

Stress Linked to Memory?

(Ivanhoe Newswire) — Stress is a term commonly used today, and we know it can have an impact on one´s mental and physical well-being. Now researchers are saying it may affect your memory too!

New research out of State University in New York, uncovered a neural mechanism that directly links repeated stress with impaired memory. Stress hormones are known to influence the prefrontal cortex (PFC), a brain region that controls high level "executive" functions such as working memory and decision making.

"Previous work has shown that chronic stress impairs PFC-mediated behaviors, like mental flexibility and attention. However, little is known about the physiological consequences and molecular targets of long-term stress in PFC, especially during the adolescent period when the brain is more sensitive to stressors," Dr. Zhen Yan, from the State University of New York at Buffalo, was quoted saying.

Using juvenile rats, Yan and colleagues examined whether repeated stress had a negative influence on glutamate receptors. Glutamate signaling plays a critical role in PFC function. They found that in response to repeated stress, there was a significant loss of glutamate receptors, which resulted in a deficit of PFC-mediated cognitive processes. The researchers went on to identify the molecular mechanisms that linked stress with the decrease in glutamate receptors and demonstrated that if they blocked these mechanisms, the stress-induced decrease in both glutamate receptors and recognition memory could be prevented.

Taken together, the findings identify a loss of glutamate receptors as an important target of repeated stress and link chronic stress with abnormal PFC function.

"Since PFC dysfunction has been implicated in various stress-related mental disorders, delineating molecular mechanisms by which stress affects the PFC should be critical for understanding the role of stress in influencing the disease process," Dr. Yan was quoted saying.

SOURCE: Cell Press, March 2012.