Anne-Marie Linnen’s research while affiliated with Concordia University and other places

Oxytocin promotes social affiliation in humans. However, the mechanisms underlying this phenomenon require further elucidation. The present study investigated the influence of intranasal oxytocin on basic emotional processing in men and women, using an emotion-modulated startle response paradigm. Eighty-four participants self-administered 24 IU of intranasal oxytocin or saline and completed an assessment of the acoustic startle reflex, using electromyography (EMG), with varying emotional foregrounds. Oxytocin had no impact on the affective modulation of the startle eyeblink response, but significantly diminished the acoustic startle reflex irrespective of the emotional foreground. The results suggest that oxytocin facilitates pro-social behavior, in part, by attenuating basic physiological arousal. Oxytocin’s dampening effect on EMG startle could possibly be used as an inexpensive marker of oxytocin’s effect on limbic brain circuits.

Evidence suggests that intranasal oxytocin enhances the perception of emotion in facial expressions during standard emotion identification tasks. However, it is not clear whether this effect is desirable in people who do not show deficits in emotion perception. That is, a heightened perception of emotion in faces could lead to “oversensitivity” to the emotions of others in non-clinical participants. The goal of this study was to assess the effects of intranasal oxytocin on emotion perception using ecologically-valid social and non-social visual tasks. Eighty-two participants (42 women) were administered a 24IU dose of intranasal oxytocin or a placebo in a double-blind, randomized experiment, and then completed the perceiving and understanding emotion components of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). In this test, emotion identification accuracy is based on agreement with a normative sample. As expected, participants administered intranasal oxytocin rated emotion in facial stimuli as expressing greater emotional intensity than those given a placebo. Consequently, accurate identification of emotion in faces, based on agreement with a normative sample, was impaired in the oxytocin group relative to placebo. No such effect was observed for tests using non-social stimuli. The results are consistent with the hypothesis that intranasal oxytocin enhances the salience of social stimuli in the environment, but not non-social stimuli. The present findings support a growing literature showing that the effects of intranasal oxytocin on social cognition can be negative under certain circumstances, in this case promoting “oversensitivity” to emotion in faces in healthy people.

Background : There is increasing evidence that oxytocin promotes empathy in humans. However, research on oxytocin and emotion recognition, a fundamental component of empathy, has yielded inconsistent results. Part of the problem is that studies have focused on limited, and varying, categories of emotional stimuli. Therefore, we investigated the effect of intranasal oxytocin on the identification of seven basic emotions (happiness, sadness, fear, excitement, surprise, disgust, and anger) using social and non-social stimuli, and we explored the effect of oxytocin on conceptual understanding of emotion. Method : Eighty-two participants were administered a 24IU dose of intranasal oxytocin or placebo in a double-blind experiment. Participants completed the perceiving (faces, designs) and understanding (blends, changes) emotion components of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) 120 minutes after drug administration. Results : Contrary to our prediction, standardized scores for accurately detecting emotions during the faces task of the MSCEIT were lower following oxytocin administration than placebo (F(1,80) = 8.861, p<.01, η2=.10). Accuracy ratings worsened following oxytocin because participants rated all emotions with greater intensity, particularly facial expressions of surprise and disgust. Oxytocin did not influence performance on tasks related to understanding emotions or tasks using non-social stimuli. Conclusions : Oxytocin appears to influence the recognition of facial expressions of emotion by increasing the perceived intensity of the emotion, while having no effect on more complex processing (i.e., understanding emotion). The present findings further support the view that oxytocin influences social information processing by increasing the salience of emotional stimuli, which may have positive or negative effects depending on context.

The administration of oxytocin promotes prosocial behavior in humans. The mechanism by which this occurs is unknown, but it likely involves changes in social information processing. In a randomized placebo-controlled study, we examined the influence of intranasal oxytocin and placebo on the interference control component of inhibition (i.e. ability to ignore task-irrelevant information) in 102 participants using a negative affective priming task with sad, angry, and happy faces. In this task, participants are instructed to respond to a facial expression of emotion while simultaneously ignoring another emotional face. On the subsequent trial, the previously-ignored emotional valence may become the emotional valence of the target face. Inhibition is operationalized as the differential delay between responding to a previously-ignored emotional valence and responding to an emotional valence unrelated to the previous one. Although no main effect of drug administration on inhibition was observed, a drug×depressive symptom interaction (β=-0.25; t=-2.6, p<0.05) predicted the inhibition of sad faces. Relative to placebo, participants with high depression scores who were administered oxytocin were unable to inhibit the processing of sad faces. There was no relationship between drug administration and inhibition among those with low depression scores. These findings are consistent with increasing evidence that oxytocin alters social information processing in ways that have both positive and negative social outcomes. Because elevated depression scores are associated with an increased risk for major depressive disorder, difficulties inhibiting mood-congruent stimuli following oxytocin administration may be associated with risk for depression.

Oxytocin facilitates pro-social behaviour and is proposed as a regulatory factor controlling stress reactivity. Previous research on oxytocin and stress has focused on achievement-related stressors among male participants. The aims of the study were to (1) examine the influence of oxytocin on the affective and cortisol response to the Yale Interpersonal Stressor (YIPS), a live social rejection paradigm, and (2) to replicate the finding that women exhibit a greater cortisol response to interpersonal stress than men (Stroud et al. 2002). Sex differences in stress responses: Social rejection versus achievement stress. Biol Psychiat 53:318-327. Ninety-six undergraduate students underwent the YIPS, where participants were excluded from two separate conversations by two same-sex confederates. Salivary cortisol concentrations and mood were repeatedly measured throughout the study. Participants were administered, in a double-blind design, a single dose of intranasal oxytocin (24 IU) or placebo prior to beginning the YIPS. The YIPS elicited a significant negative mood response that was more pronounced in females than in males. However, no significant cortisol response to the stressor and no sex difference in cortisol reactivity were observed. A significant effect of drug condition on cortisol levels was observed. Participants who were administered oxytocin exhibited a decrease in cortisol levels, relative to placebo, during the YIPS, F (4, 184)=4.50, p<0.05. The study failed to replicate the sex difference in the cortisol response to interpersonal stress reported by Stroud et al. (2002). Intranasal oxytocin, however, appeared to reduce cortisol concentrations during an interpersonal challenge.

Research suggests the experimental manipulation of oxytocin facilitates positive interactions, cooperation, and trust. The mechanism by which oxytocin influences social behavior is not well understood. We explored the hypothesis that oxytocin alters how people perceive themselves, which could be one mechanism by which oxytocin promotes prosocial behavior. In a between-subject, randomized, and double-blind experiment, 100 university students received a 24 I.U. dose of intranasal oxytocin or placebo, and then completed the Revised NEO Personality Inventory (NEO-PI-R) and other self-report measures 90 min later. Intranasal oxytocin increased ratings of NEO-PI-R extraversion and openness to experiences [F(1,98) = 4.910, p = .025, partial η (2) = .05; F(1,98) = 6.021, p = .016, partial η (2) = .06], particularly for the following facets: positive emotions (d = 0.48, p < .05), warmth (d = 0.47, p < .05), openness to values (d = 0.45, p < .05) and ideas (d = 0.40, p < .05), trust (d = 0.44, p < .05), and altruism (d = 0.40, p < .05). Oxytocin had no influence on ratings of negative emotionality, conscientiousness, rejection sensitivity, depression, worry, self-esteem, and perceived social support. The administration of oxytocin improved participants' self-perceptions of their personality, at least for certain traits important for social affiliation. Increased positive self-referential processing may be one mechanism by which oxytocin promotes positive social behaviors.

Recent evidence suggests self-administration of intranasal oxytocin may facilitate social interaction by attenuating the stress response to interpersonal conflict. Currently, no published research has documented whether intraindividual factors moderate the effect of intranasal oxytocin on the emotional response to stress. The aim of the present study was to determine whether coping style moderates the effect of intranasal oxytocin on mood in response to an interpersonal stressor in healthy men and women. In a double-blind placebo-controlled experiment, 100 undergraduate students (50 women) participated in the Yale Interpersonal Stressor (YIPS: Stroud, Tanofsky-Kraff, Wilfley, & Salovey, 2000), a live social rejection paradigm. Prior to the YIPS, participants were randomly assigned to self-administer either intranasal oxytocin (24 IU) or a placebo. Coping was measured using the Coping Inventory for Stressful Situations. Multiple regression analyses predicting stress-related changes in anxiety revealed a significant Drug × Emotion-oriented coping × Sex interaction [pr2 = .06, b = 6.074, t(91) = -2.526, p = .014]. Follow-up analyses using simple slopes revealed self-administration of intranasal oxytocin reduced anxiety in response to the YIPS relative to the placebo in women high in emotion-oriented coping [b = 4.487, t(91) = 2.09, p < .05], but not in women low in emotion-oriented coping, or men. The results suggest that intraindividual factors modulate the effect of intranasal oxytocin on the affective response to stress. Intranasal oxytocin appears to be particularly beneficial to women who endorse high levels of emotion-oriented coping, who may be vulnerable to the negative impact of stress.

Oxytocin is known to promote social affiliation. The mechanism by which this occurs is unknown, but it may involve changes in social information processing. In a placebo-controlled study, we examined the influence of intranasal oxytocin on effortful and automatic attentional shifting in 57 participants using a spatial cueing task with emotional and neutral faces. For effortful processing, oxytocin decreased the speed of shifting attention to sad faces presented for 750 ms and facilitated disengagement from right hemifield sad and angry faces presented for 200 ms. For automatic processing, symptoms of depression moderated the relationship between drug and disengagement. Oxytocin attenuated an attentional bias to masked angry faces on disengagement trials in persons with high depression scores. Oxytocin's influence on social behavior may occur, in part, by eliciting flexible attentional shifting in the early stages of information processing.