Stress and Memory: A Selective Review on Recent Developments in the Understanding of Stress Hormone Effects on Memory and Their Clinical Relevance.

Stress causes a neuroendocrine response cascade, leading to the release of catecholamines and glucocorticoids (GCs). GCs influence learning and memory by acting on mineralocorticoid (MR) and glucocorticoid (GR) receptors. Typically, GCs enhance the consolidation of memory processing at the same time as impairing the retrieval of memory of emotionally arousing experiences. The present selective review addresses four recent developments in this area. First, the role of the endocannabinoid system in mediating the rapid, nongenomic effects of GCs on memory is illustrated in rodents. Subsequently, studies on the impact of the selective stimulation of MRs on different memory processes in humans are summarised. Next, a series of human experiments on the impact of stress or GC treatment on fear extinction and fear reconsolidation is presented. Finally, the clinical relevance of the effects of exogenous GC administration is highlighted by the description of patients with anxiety disorders who demonstrate an enhancement of extinction-based therapies by GC treatment. The review highlights the substantial progress made in our mechanistic understanding of the memory-modulating properties of GCs, as well as their clinical potential.

Role of the endocannabinoid system in regulating glucocorticoid effects on memory for emotional experiences.

Glucocorticoids, stress hormones released from the adrenal cortex, have potent modulatory effects on emotional memory. Whereas early studies focused mostly on the detrimental effects of chronic stress and glucocorticoid exposure on cognitive performance and the classic genomic pathways that mediate these effects, recent findings indicate that glucocorticoids exert complex and often rapid influences on distinct memory phases. Specifically, glucocorticoids have been shown to enhance memory consolidation of emotionally arousing experiences, but to impair memory retrieval and working memory during emotionally arousing test situations. Furthermore, growing evidence indicates that these different glucocorticoid effects depend on a nongenomically mediated interaction with emotional arousal-induced noradrenergic activation within the basolateral complex of the amygdala. In this paper, we present a model suggesting that the endocannabinoid system, a lipid-based retrograde signaling system, might play an important role in mediating such rapid glucocorticoid influences on the noradrenergic system in modulating memory of emotionally arousing experiences.