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Episodic memories can be modified when exposed to new and related information. This phenomenon, known as memory updating, is generally thought to be adaptive but can also lead to incorporating false information into a memory trace. Given the well-known effects of stress on episodic memory, we used a false information paradigm to investigate if acute stress during memory updating (i.e., post-learning stage) affected false memory formation. In a between-subject design, young healthy participants completed the initial phases of the misinformation experiment - they studied an event via a slideshow and then were exposed a related narrative that contained misleading information about that event. After, half of the participants were exposed to acute psychosocial stress and the other half completed a control task. Once stress levels returned to baseline, all of the participants completed the final phase of the experiment, which was a memory test for slideshow that included items containing true facts and misinformation. Participants in the stress condition showed a reduced misinformation effect and were better able to discriminate true from false information compared to control participants. This pattern of results held even when participants were tested on the same memory test after a multiple day delay, illustrating the long-lasting effects of stress on false memory formation specifically, and memory updating generally. We discuss how our results add to the understanding of the time-dependent factors that moderate stress effects on memory, and speculate how stress effects on memory updating can be positive, by limiting intrusions into encoded events, but also negative, by limiting the ability to integrate information with other concepts, harming memory generalization.

SummaryIn this review we summarize the results and conclusions of five studies as presented in a symposium at the 42nd annual meeting of the International Society for Psychoneuroendocrinology, in New York in September 2012. Oxytocin administration has received increasing attention for its role in promoting positive social behavior and stress regulation, and its potential as a therapeutic intervention for addressing various aspects of psychiatric disorders. However, it has been noted that the observed effects are not uniformly beneficial. In this paper we present five new studies each concluding that contextual and interindividual factors moderate the effects of oxytocin, as well as peripheral oxytocin levels. These findings are in accordance with the recent idea that oxytocin administration may increase sensitivity to social salience cues and that the interpretation of these cues may be influenced by contextual (i.e. presence of a stranger versus friend) or interindividual factors (i.e. sex, attachment style, or the presence of psychiatric symptoms). When social cues in the environment are interpreted as “safe” oxytocin may promote prosociality but when the social cues are interpreted as “unsafe” oxytocin may promote more defensive and, in effect, “anti-social” emotions and behaviors. Likewise, oxytocin appears to promote such agonistic tendencies in individuals who are chronically pre-disposed to view the social milieu in uncertain and/or in negative terms (e.g., those with borderline personality disorder, severe attachment anxiety and/or childhood maltreatment). In all, these studies in pre-clinical animal, healthy humans and patients samples further reinforce the importance of considering both contextual and interindividual factors when trying to understand the role of oxytocin as a biological substrate underlying social bonding and stress regulatory processes and when studying the effects of oxytocin administration in particular in patients with (increased risk for) psychiatric disorders.

Oxytocin has known stress-reducing and attachment-enhancing effects. We thus hypothesized that oxytocin would attenuate emotional and hormonal responses to stress in borderline personality disorder (BPD). Fourteen BPD and 13 healthy control (HC) adults received 40 IU intranasal oxytocin or placebo in double-blind randomized order followed by the Trier Social Stress Test. Subjective dysphoria (Profile of Mood Changes) and plasma cortisol levels were measured. Childhood trauma history, attachment style, and self-esteem were also rated. A significant "Group × Drug × Time" interaction effect for dysphoria (p=.04) reflected a proportionately greater attenuation of stress-induced dysphoria in the BPD group after oxytocin administration. Additionally, a marginally significant "Group × Drug" interaction effect for cortisol (p=.10) reflected a tendency toward greater attenuation of the stress-induced cortisol surge in the BPD group after oxytocin administration. In the combined sample, the oxytocin-placebo difference in the emotional stress reactivity was significantly predicted by childhood trauma alone (p=.037) and combined with self-esteem (p=.030), whereas the oxytocin-placebo difference in cortisol stress reactivity was predicted only by insecure attachment (p=.013). Results suggest that oxytocin may have a beneficial impact on emotional regulation in BPD, which merits further investigation and could have important treatment implications.