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

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.

Keywords: context memory; human memory consolidation; item-context binding; post-encoding stress.

Figure 1

Examples for stimuli used during encoding (a) and test (b). Stimuli were presented in color in the study.

Figure 2

Schematic depiction of the experimental timeline with approximate durations of the different components.

Figure 3

Salivary cortisol before encoding (Sample 1), after the stress/control manipulation (Sample 2) and before the final test in Session 2 (Sample 3) in males and females. Log-transformed cortisol values (original units: nmol/L) are shown. Error bars represent standard errors of means.

Figure 4

Proportion of hits for men and women in the cold pressor stress (CPS) and control group (a) and in CPS responders, non-responders and the control group (b). Error bars represent standard errors of means. * significant at the 0.05 level, ^† marginally significant.

Figure 5

Relationship between relative cortisol increase and proportional hit rate in male responders.