Stress-Induced Increase in Cortisol Negatively Affects the Consolidation of Contextual Elements of Episodic Memories.

Matthew Sabia,Almut Hupbach

doi:10.3390/brainsci10060358

Abstract

Stress can modulate episodic memory in various ways. The present study asks how post-encoding stress affects visual context memory. Participants encoded object images centrally positioned on background scenes. After encoding, they were either exposed to cold pressure stress (CPS) or a warm water control procedure. Forty-right hours later, participants were cued with object images, and for each image, they were asked to select the background scene with which it was paired during study among three highly similar options. Only male but not female participants reacted with a significant increase in salivary cortisol to CPS, and the stress and control group did not differ in recognition performance. Comparing recognition performance between stress responders and non-responders, however, revealed a significant impairment in context memory in responders. Additionally, proportional increase in cortisol was negatively correlated with the number of correctly recognized scenes in responders. Due to the small number of responders, these findings need to be interpreted with caution but provide preliminary evidence that stress-induced cortisol increase negatively affects the consolidation of contextual elements of episodic memories.

Highlights

Stress is a powerful modulator of learning and memory
Cortisol can pass through the blood–brain barrier and binds to mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) that are expressed in brain areas crucially involved in learning and memory, the hippocampus [1,2]
We presented participants with object images that were superimposed on scene images and asked about the impact of post-encoding stress on scene recognition

Summary

Introduction

Stress activates (a) the sympathetic nervous system, leading to a rapid release of catecholamines from the adrenal medulla, and (b) the hypothalamus-pituitary-adrenocortical axis, leading to a slower release of glucocorticoids such as cortisol from the adrenal cortex. Cortisol can pass through the blood–brain barrier and binds to mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) that are expressed in brain areas crucially involved in learning and memory, the hippocampus [1,2]. Stress-related increases in cortisol lead to the occupation of GRs, which directly affect hippocampal processes; for a review, see [3]. Stress can impair or enhance episodic memory, and the specific direction of influence depends on the interaction of many factors, including the intensity of the stress response, concurrent catecholamine activation, the hormonal state of the stressed individual, the emotionality and ecological validity of the memory content, and importantly, the timing of the stressor in relation to the memory stage

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Results

Discussion

Conclusion