20 Aug 1998

Stress and glucocorticoids (hormones produced in response to stress) are known to impair the acquisition and storage of new information. But stress also hinders the ability to recall memories, according to a study published by Benno Roozendaal and colleagues from the University of California, Irvine, in the current Nature. Rats proved unable to remember their way around a maze when exposed to a stressful event (a small electric shock) 30 minutes before the task-but not two minutes or four hours before. This time-dependent effect on memory performance correlates with the levels of circulating glucocorticoids-highest at 30 minutes-suggesting a connection between the stressful event, the hormone pulse, and the disruption of memory. Injecting non-stressed rats with glucocorticoids also resulted in the same response. Furthermore, prevention of glucocorticoid production was able to reverse the stress-induced effects on memory retrieval.—June Kinoshita