Post-encoding stress and spatial memory consolidation: No significant associations with cortisol and DHEA reactivity.

Memory consolidation is enhanced by post-encoding stress via cortisol, although the role of dehydroepiandrosterone (DHEA) remains uncertain. This study investigated the effect of the Maastricht Acute Stress Test (MAST) on psychological and hormonal (salivary cortisol and DHEA) responses and performance on a virtual reality object-location memory (OLM) task. The association between hormonal reactivity and OLM task performance was also investigated. Fifty-four participants aged 18-23 were randomly assigned to a stress group (n = 30) and a control group (n = 24). Participants completed an encoding trial of the OLM task and the MAST/control procedure in an acquisition session. A retrieval session 24 h later included verbal object and visual location recognition tests, as well as an object-context binding (OCB) trial. Results showed that the stress group reported significantly higher state anxiety and negative affect after the MAST, perceived as more stressful, painful, and unpleasant. This group also exhibited a significant increase in cortisol and DHEA levels in response to the MAST. Controlling for age, participants in the stress condition made fewer errors in recognising semantically unrelated objects and tended to complete the OCB trial in a shorter time. In addition, no associations were found between cortisol or DHEA reactivity and memory performance in either the stress group or the control group. Our data indicate that post-encoding stress enhances consolidation; however, no association was found between hormonal reactivity and this process, suggesting that these endocrine responses do not directly support the observed improvement in memory consolidation.