Neurobiological mechanisms of stress and glucocorticoid effects on learning and memory: Implications for stress disorders on earth and in space

Abstract

Over the last decades considerable evidence has accumulated indicating that glucocorticoids - stress hormones released from the adrenal cortex - are crucially involved in the regulation of emotional memory. Specifically, glucocorticoids have been shown to enhance memory consolidation of emotionally arousing, stressful experiences, but to impair memory retrieval and working memory during emotionally arousing test situations. Here we review findings from both animal and human experiments and present an integrated perspective of how these opposite glucocorticoid effects might act together to serve adaptive processing of emotionally significant information. Furthermore, as intense emotional memories also play a crucial role in the pathogenesis and symptomatology of anxiety disorders, such as posttraumatic stress disorder (PTSD), we discuss to what extent the basic findings on glucocorticoid effects on emotional memory might have implications for the understanding and treatment of this clinical condition. Moreover, because space flight represents an extremely stressful condition, the reviewed findings on glucocorticoids might have important implications regarding the regulation of emotional memory and psychological health problems in space travelers.