With National Science Foundation support, Dr. Weekes and colleagues will conduct a three-year investigation into the relationships among psychological stressors, stress hormone levels, memory functioning, and electrical brain activity. In one study, they will investigate the effects of group differences (high vs. low) in chronic stress hormone secretion on memory performance and electrical brain activity during both the encoding and retrieval stages of a verbal memory task. In a second study, they will investigate the associations among the acute stress response, memory performance and electrical brain activity during both the encoding and retrieval stages of a verbal memory task. These studies explore suggestions from various prior studies that concentrations of stress hormones can significantly impact memory functioning. While studies suggest a detrimental effect of chronically high levels of stress hormones on memory, there is less known about the nature of the relationship between acutely high levels of stress hormones and memory. The strongest effects of chronic and acute levels of stress hormones on memory appear to be on verbal memory. However, it is unclear which stage of memory processing may be most sensitive to stress hormone levels, with some studies suggesting an effect on encoding or storage, and others on retrieval. Further, a number of recent studies have found effects of stress hormones on electrical brain activity. Few studies have questioned whether stress-induced changes in memory functioning are related to changes in regional electrophysiological activity. This is a particularly important field of inquiry given the evidence that the most significant effects of stress on such brain regions as the hippocampus and prefrontal cortex are electrophysiological in nature. The elucidation of these relationships will lead to a better understanding and better treatment options for individuals suffering from stress- or stress hormone-related memory deficits. These populations include, but are not limited to, individuals with Cushing's disease, Post-Traumatic Stress Disorder, schizophrenia, depression and the elderly.
