Ever noticed how “episodes” associated with many mental illnesses are triggered by stress? If you have ever been in a highly stressful situation or are no stranger to chronic stress, then you know that it can disrupt your mental processes and cause havoc on your emotions. New findings, published in the March 8 issue of the journal Neuron, reveal that there’s a link between impaired memory and repeated stress.
Researchers from the State University of New York at Buffalo, led by Dr. Zhen Yan, found the neural mechanism involved in memory impairment when stressors are present. The brain’s working memory and decision making functions are high level “executive” functions controlled by the prefrontal cortex (PFC) and it has already been scientifically proven by other studies that stress hormones influence this brain region.
“Previous work has shown that chronic stress impairs PFC-mediated behaviors, like mental flexibility and attention,” explains Dr. Yan. “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.”
Using juvenile rats, Dr. Yan and his team looked at how glutamate receptors in the rats’ brain were affected when subjected to repeated stress. Glutamate receptors are critical to PFC functions. The team’s findings reveal that repeated stress resulted in a significant decrease in glutamate receptors which, in turn, caused inadequate PFC-mediated cognitive processes. After identifying the molecular mechanisms directly involved in the process, the researchers also determined that blocking these mechanisms could prevent the loss of glutamate receptors and recognition memory induced by repeated stress.
Based on these results, Dr. Yan and his team conclude that, “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.”