Stress, memory and mental illness
By Liz Lockhart
Having once suffered from a stress disorder, I know, only too well, that stress can make thinking clearly feel as though it is impossible. New research shows us that stress can impact on a neural mechanism which can cause this feeling and can also impair memory.
The study was lead by Dr. Zhen Yan of the State University of New York and can be found in the journal Neuron which is published by Cell Press. It gives us an insight into why stress responses can be a trigger for several mental illnesses.
Functions such as working memory and decision are influenced by the prefrontal cortex (PFC) of the brain. Stress hormones are known to affect the PFC.
Dr. Yan said ‘Previous work has shown that chronic stress impairs PFC-mediated behaviours, 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.’
A negative influence on glutamate receptors after repeated stress was looked for by Dr. Yan and his colleagues, as glutamate signalling poays a vital role in PFC functioning. They discovered that after repeated stress there is a considerable loss of glutamate receptors. This results in a lack of PFC-mediated cognitive processes.
The researchers also found the molecular mechanisms that connect stress with this decrease in glutamate receptors. Furthermore they blocked these mechanisms, and found that the stress-induced decrease could be avoided.
Dr. Yan concludes ‘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.’