| Previous research from multiple levels of investigation indicates that glucocorticoids (including cortisol, corticosterone and hydrocortisone) disproportionately affect hippocampal function and the form of cognition that the hippocampus subserves, explicit memory. However, some studies suggest that glucocorticoids may affect structures within the frontal lobe as well as attention and working memory. Thus, it is not clear whether these steroid hormones specifically target the hippocampus and explicit memory or if the effects are more ubiquitous. By simultaneously measuring event-related potentials and behavioral performance in tasks designed to tap particular cognitive and neural processes, the present study examined the effects of an acute hydrocortisone exposure on healthy humans. The results indicate that hydrocortisone solely targeted explicit memory. Specifically, hydrocortisone impaired performance in a test of recognition memory for faces with a half-hour delay. In addition, in the face recognition memory task with a short delay, the drug altered the P600 component, an electrophysiological response indexing recognition memory and possibly hippocampal activity. Meanwhile, no impairments were found in attention and working memory. These results indicate that glucocorticoids specifically affect explicit memory and perhaps the hippocampus. |
