Oxytocin sharpens self-other perceptual boundary

The Interplay of Oxytocin and Attachment in Schizophrenic Patients: An fMRI Study

BACKGROUND

Attachment theory offers an important framework for understanding interpersonal interaction experiences. In the present study, we examined the neural correlates of attachment patterns and oxytocin in schizophrenic patients (SZP) compared to healthy controls (HC) using fMRI. We assumed that male SZP shows a higher proportion of insecure attachment and an altered level of oxytocin compared to HC. On a neural level, we hypothesized that SZP shows increased neural activation in memory and self-related brain regions during the activation of the attachment system compared to HC.

METHODS

We used an event-related design for the fMRI study based on stimuli that were derived from the Adult Attachment Projective Picture System to examine attachment representations and their neural and hormonal correlates in 20 male schizophrenic patients compared to 20 male healthy controls.

RESULTS

A higher proportion of insecure attachment in schizophrenic patients compared to HC could be confirmed. In line with our hypothesis, Oxytocin (OXT) levels in SZP were significantly lower than in HC. We found increasing brain activations in SZP when confronted with personal relevant sentences before attachment relevant pictures in the precuneus, TPJ, insula, and frontal areas compared to HC. Moreover, we found positive correlations between OXT and bilateral dlPFC, precuneus, and left ACC in SZP only.

CONCLUSION

Despite the small sample sizes, the patients' response might be considered as a mode of dysregulation when confronted with this kind of personalized attachment-related material. In the patient group, we found positive correlations between OXT and three brain areas (bilateral dlPFC, precuneus, left ACC) and may conclude that OXT might modulate within this neural network in SZP.

The role of oxytocin in modulating self-other distinction in human brain: a pharmacological fMRI study

Self-other distinction is crucial for human interaction. Although with conflicting results, studies have found that oxytocin (OT) sharpens the self-other perceptual boundary. However, little is known about the effect of OT on self-other perception, especially its neural basis. Moreover, it is unclear whether OT influences self-other discrimination when the other is a child or an adult. This double-blind, placebo-controlled study investigated the effect of OT on self-face perception at the behavioral and neural levels. For the stimuli, we morphed participants' faces and child or adult strangers' faces, resulting in 4 conditions. After treatment with either OT or placebo, participants reported whether a stimulus resembled themselves while being scanned using functional magnetic resonance imaging (fMRI). Behavioral results showed that people judged adult-morphed faces better than child-morphed faces. Moreover, fMRI results showed that the OT group exhibited increased activity in visual areas and the inferior frontal gyrus for self-faces. This difference was more pronounced in the adult-face condition. In multivariate fMRI and region of interest analyses, better performance in the OT group indicated that OT increased self-other distinction, especially for adult faces and in the left hemisphere. Our study shows a significant effect of OT on self-referential processes, proving the potential effect of OT on a left hemisphere self-network.

A randomized placebo-controlled intranasal oxytocin study on first impressions and reactions to social rejection

Oxytocin is central to pair-bonding in non-human animals. We assessed effects of intranasal oxytocin on bond formation between two opposite-sex strangers. In a double-blind placebo-controlled design, 50 pairs of one man and one woman received oxytocin or placebo spray intranasally. After treatment, they played a social interaction game, followed by tasks designed to measure first impressions of the opposite-sex co-participant, and a virtual ball-tossing game (cyberball), designed to measure reactions to rejection by the co-participant. We found no evidence that intranasal oxytocin can improve first impressions of an opposite-sex stranger, and some Bayesian support against this hypothesis. For rejection sensitivity, we observed a sex-and-context-dependent drug effect on post-ostracism mood ratings, consistent with recent studies indicating that interindividual variation and social context can interact with intranasal oxytocin effects. Further research is needed to determine the generalisability of these findings, i.e. if oxytocin can improve first impressions in humans under different conditions.

Childhood emotional abuse and problematic social networking sites use in a sample of Italian adolescents: The mediating role of deficiencies in self-other differentiation and uncertain reflective functioning

OBJECTIVE

Childhood emotional abuse (CEA) is associated with various negative mental health outcomes. This study aimed to investigate the association between CEA and problematic social networking site (SNS) use in a sample of Italian adolescents.

DESIGN

Using structural equation modeling, the study examined whether the relationship between CEA and problematic SNS use was sequentially mediated by self-other differentiation and uncertain reflective functioning in 1308 Italian adolescents (628 males, age range 13-19 years).

RESULTS

A history of CEA was positively associated with problematic SNS use. Furthermore, deficiencies in self-other differentiation and uncertain reflective functioning partially mediated the relationship between CEA and problematic SNS use.

CONCLUSIONS

The present study provides additional insight into the psychological dynamics underpinning problematic SNS use among adolescents. The clinical implications of these findings are discussed.

Self-other distinction and borderline personality disorder features: Evidence for egocentric and altercentric bias in a self-other facial morphing task

Self-other distinction (SOD) refers to the ability to distinguish one's own body, actions, and mental representations from those of others. Problems with SOD are considered to be a key feature of borderline personality disorder (BPD). However, empirical studies on SOD in BPD are scarce. Here, we present a study providing preliminary support for the usefulness and validity of a self-other facial morphing task to capture the capacity for SOD in a sample of nonclinical participants high (n = 30) and low (n = 32) in BPD features. Participants had to watch a video sequence in which their own face was gradually morphed into the face of an unfamiliar other (self-to-other) or vice versa (other-to-self), requiring them to indicate at which point they judged the morph to look more like the target face than the starting face. Consistent with predictions, results showed that participants in the high-BPD group judged the morph to look like themselves for longer in the self-to-other direction (suggestive of egocentric bias), but only with a relatively more attractive target face. In the other-to-self direction, the high-BPD group had more difficulty recognizing their own face (i.e., an altercentric bias), but this time only with the relatively less attractive face. Further research is needed to replicate these findings in clinical samples, but overall they suggest that the current task might be suited to investigate SOD problems in BPD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Eye-Tracking Reveals a Role of Oxytocin in Attention Allocation Towards Familiar Faces

Visual attention directed towards the eye-region of a face emerges rapidly, even before conscious awareness, and regulates social interactions in terms of approach versus avoidance. Current perspectives on the neuroendocrine substrates of this behavioral regulation highlight a role of the peptide hormone oxytocin (OXT), but it remains unclear whether the facilitating effects of OXT vary as a function of facial familiarity. Here, a total of 73 healthy participants was enrolled in an eye-tracking experiment specifically designed to test whether intranasal OXT (24 IU) augments gaze duration toward the eye-region across four different face categories: the participants' own face, the face of their romantic partner, the face of a familiar person (close friend) or an unfamiliar person (a stranger). We found that OXT treatment induced a tendency to spend more time looking into the eyes of familiar persons (partner and close friend) as compared to placebo. This effect was not evident in the self and unfamiliar conditions. Independent of treatment, volunteers scoring high on autistic-like traits (AQ-high) spent less time looking at the eyes of all faces except their partner. Collectively, our results show that the OXT system is involved in facilitating an attentional bias towards the eye region of familiar faces, which convey safety and support, especially in anxious contexts. In contrast, autistic-like traits were associated with reduced attention to the eye region of a face regardless of familiarity and OXT-treatment.

The role of impairments in self-other distinction in borderline personality disorder: A narrative review of recent evidence

Impairments in maintaining a differentiated sense of "self" and "other" are thought to be a central feature of borderline personality disorder (BPD). However, studies directly focusing on self-other distinction (SOD) in BPD are scarce, and these findings have not yet been integrated with novel insights into the neural mechanism involved in SOD. Here, we present a narrative review of recent behavioral and neuroimaging findings focusing on impairments in SOD in BPD. Behavioral findings of SOD at the embodied level provide preliminary evidence for impairments in multisensory integration in BPD. Furthermore, both behavioral and neuroscientific data converge to suggest that SOD impairments in BPD reflect an inability to shift between self and other representations according to task demands. Research also suggests that disruptions in infant-caregiver synchrony may play a role in the development of these impairments. Based on these findings, we present a new, integrative model linking impairments in SOD to reduced neural and behavioral synchrony in BPD. The implications of these findings for future research and clinical interventions are outlined.

Intranasal oxytocin decreases self-oriented learning

RATIONALE

Oxytocin has been found to play an important role in human social cognition and social interaction. Over the last two decades, surge studies have been conducted to investigate how oxytocin impacts other-oriented processes, such as trust and generosity (Zak et al. in PLoS ONE 2(11):e1128, 2007); however, the examination of the effect of oxytocin on self-related processes was relatively inadequate. Appropriate and efficient social interactions require both self- and other-related information processing. Recent studies have found that intranasal oxytocin (IN-OT) influences the self-related process, although the results have been mixed. The computational process underlying the effects of IN-OT on self-processing remains unknown.

OBJECTIVES

We aim to investigate the effect of IN-OT on self-oriented learning across different contexts (self-other independent vs. self-other dependent) and uncover the process by which IN-OT affects dynamic behavior changes.

METHODS

We performed two double-blind, placebo-controlled studies and used reinforcement learning theory to integrate action and related feedback for participants' behaviors.

RESULTS

In study 1, IN-OT decreased self-oriented reward learning when self-oriented learning and prosocial (other-oriented) learning were assessed separately. These effects were partially due to the OT-related increase in choice variability during self-oriented learning. In study 2, IN-OT also decreased learning performance during self-oriented reward learning when self-related and other-related rewards were present together. These effects occurred at an early stage of the learning process and could be moderated by the participants' social value orientation. Our findings show that OT attenuates the process of self-oriented learning and provides an underlying computational process.

CONCLUSIONS

Our findings shed new light on the dynamics of IN-OT's effects on human self-oriented learning processes. For future studies on OT effects on self-oriented learning, individual factors such as social value orientation should be taken into consideration in research development and analysis.

Oxytocin weakens self-other distinction in males during empathic responses to sadness: an event-related potentials study

By making use of event-related potential (ERP) technology, a randomized, double-blind, between-subject design study was performed in order to investigate whether OXT can weaken men’s self-other distinction during empathic responses to sad expressions. In the two experimental tasks, 39 male subjects were asked to either evaluate the emotional state shown in a facial stimulus (other-task) or to evaluate their own emotional responses (self-task). The results revealed that OXT reduced the differences in P2 (150–200 ms) amplitudes between sad and neutral expressions in the self-task but enhanced P2 to sad expressions in the other-task, indicating OXT’s role in integrating the self with others instead of separating them. In addition, OXT also reduced the LPC (400–600 ms) amplitudes between sad-neutral expressions in the self-task, implying that OXT’s weakening effects on the self-other distinction could occur at both the early and late cognitive control stages of the empathic response.

Effect of intranasal oxytocin administration on self-other distinction: Modulations by psychological distance and gender

Preliminary evidence indicates that intranasal oxytocin (OT) administration modulates one's ability to distinguish oneself from others (i.e., self-other distinction). However, previous findings on this topic are contradictory. The current study addressed this issue by (i) using a novel perceptual matching task examining self-other distinction compared to both close and distant others, and (ii) tentatively exploring potential modulations by gender. In a double-blind, placebo-controlled, randomized OT administration study, 100 participants (50 males and 50 females) were randomized to receive intranasal spray of 24 IU OT or placebo (PL). Afterwards, participants completed a geometry perceptual matching task in which different shapes were paired to the self, a friend, or a stranger. Participants were then asked to judge whether each pair of shapes and labels was correctly matched. The results revealed that compared to PL administration, OT facilitated distinction between the self and a friend in males but not in females. These findings provide insights for debates on the role of OT in self-other distinction by revealing modulations by psychological distance and gender, which have implications for the potential clinical applications of OT.

Oxytocin modulation of self-referential processing is partly replicable and sensitive to oxytocin receptor genotype

Intranasal oxytocin (OXT) has been associated with effects on diverse social-emotional domains in humans, however progress towards a therapeutic application of OXT in disorders with social-emotion impairments is currently hampered by poor replicability. Limited statistical power and individual differences in biological factors, such as oxytocin receptor (OXTR) genetics, may have contributed to these variable findings. To this end, employing a validated oxytocin-sensitive trait judgment paradigm, we present a pharmaco-genetic study aiming at (1) replicating previous findings suggesting that intranasal oxytocin (24 IU) reduces the self-referential bias in a large sample of n = 170 male subjects, (2) determining whether variations in common receptor polymorphisms (rs237887, rs2268491, rs2254298, rs53576, rs2268498) influence sensitivity to oxytocin's behavioral effects. We confirmed that in the whole sample oxytocin influenced self-other distinction in terms of reduced decision time. However, oxytocin only influenced decision time in rs53576 G carriers, whereas effects on subsequent memory performance were only found in rs2268498 TT homozygotes. In summary, the current study partially replicates our previous findings showing that oxytocin reduces the self-referential bias and suggests that sensitivity to its effects in this domain are receptor genotype dependent.

Low Salivary Testosterone Level Is Associated With Efficient Attention Holding by Self Face in Women

Capacity to recognize one’s own face (hereinafter referred to as self face) is a fundamental component of various domains of social cognition such as empathy in humans. Previous research has demonstrated that a high level of androgen suppresses empathic behavior and social brain function. Taking these into consideration, we hypothesized that people with high androgen level show reduced response to self face. The present study examined this hypothesis by investigating the association between attentiveness towards self face, as assessed by a psychophysiological experiment, and salivary testosterone concentration. The attentional responses to self face was measured by a modified Go/NoGo task. In this task, self face or unfamiliar other’s face was presented simultaneously with Go or NoGo signal. In go trials, participants had to divert their attention from the face to a peripheral target. The reaction time (RT) for peripheral target detection in each condition was measured. In addition to behavioral data, saliva samples were collected to assay salivary testosterone concentration. The index of potency of self face to hold viewer’s attention that was computed based on RT data was regressed against salivary testosterone concentration in men and women separately. The analyses revealed that self face holds visuospatial attention more effectively in women with low than high salivary testosterone level, but no such trend was observed in men. This pattern of results indicates that low testosterone level is associated with a pronounced response to self face as we hypothesized and raises the possibility that multiple aspects of self-face processing are under the influence of endocrinological function.

Prediction-based neural mechanisms for shielding the self from existential threat

The human mind has an automatic tendency to avoid awareness of its mortality. How this protective mechanism is implemented at the neuronal level is unknown. Here we test the hypothesis that prediction-based mechanisms mediate death-denial by shielding the self from existential threat. We provide evidence that self-specific predictive processes are downregulated during the perception of death-related linguistic stimuli and that this mechanism can predict fear-of-death. Using a magnetoencephalography visual mismatch paradigm, we show that the brain's automatic prediction response to deviancy is eliminated when death words and self-face representations are coupled, but remains present when coupled to other-face or to negative words. We further demonstrate a functional link between how death impacts self-image vs. Other-image, and show that it predicts fear-of-death. Finally, we confirm this effect in a behavioral active inference experiment showing that death-related words bias perceptual judgment on facial self and other morphed video clips. Together these results lay out, for the first time, a plausible neural-based mechanism of death-denial.

Oxytocin Modulates the Cognitive Appraisal of the Own and Others Close Intimate Relationships

Close and intimate relationships are important promoters of health. Oxytocin and its association with social cognition have been investigated in a large number of studies, especially highlighting the neuropeptide's involvement in attachment behavior and intimate relationships. However, mixed findings on exogenous oxytocin application have led to the focus on moderators and mediators, suggesting that the effects are depended on specific factors - namely context and salience. The objective of the current study was to assess the effect of intranasal oxytocin on social appraisal of own and others' close intimate relationship characteristics. Different characteristics of relationships, including trust or closeness, between romantic couples (unknown and own) were assessed using the Couple Appraisal Task. In a randomized controlled double-blind cross-over within subject design, N = 71 healthy men and women were investigated after receiving first intranasal oxytocin and 2 weeks later placebo, or vice versa. We found an oxytocin-induced increase in the positive appraisal of one's own overall relationship characteristics but not in the evaluation of the relationship of others. The present study - one of the first of its kind administrating oxytocin in a repeated measures cross-over design - adds further evidence to the mediating role of oxytocin in social cognition, specifically with regard to romantic relationship characteristics.

Intranasal oxytocin modulates higher order social cognition in body dysmorphic disorder

BACKGROUND

Body dysmorphic disorder (BDD) is a psychiatric disorder with specific impairments in social cognition related to excessive concerns about one's appearance. Individuals with BDD have difficulty identifying emotional expressions and attribute internal factors for others' emotional expressions in self-referent (but not other-referent) scenarios. Given the role of oxytocin in regulating social approach behavior and social salience, we hypothesized that oxytocin would improve biases in emotion recognition, attributions, and threat interpretations in individuals with BDD, compared to healthy controls (HCs). This is the first study to examine the effects of oxytocin in people with BDD.

METHODS

Eighteen participants with BDD and 16 HCs received a single dose of 24 international units of intranasal oxytocin (Syntocinon®) or matching placebo in a randomized, placebo-controlled, within-subject crossover design. Participants completed the Emotion Recognition Task and Interpretation Questionnaire 45 min after administration.

RESULTS

Oxytocin, relative to placebo, did not improve emotion recognition accuracy in either self-referent or other-referent contexts for individuals with BDD. However, oxytocin led to greater internal attributions in other-referent contexts for those with BDD compared to HCs. Rather than reducing self-blame, oxytocin led to other-directed blame. Oxytocin did not impact threat interpretations in BDD.

CONCLUSIONS

Oxytocin may only impact specific aspects of higher order social cognition in BDD and may have unwanted effects on emotion attributions. Our results caution its clinical use in BDD.

Mind and mourning: The primacy of "we" in complicated grief

Standard models of complicated grief rely on a self-other divided mind that reflects the physical separateness of individuals. In these models, grief persists for those mourners who cannot reorganize self-and-other mental representations or adapt to identity changes after loss. However, advances in cognitive science indicate that relationships are often processed via distributed social-cognitive coding whereby individuals together form a psychologically extended common mind. I propose a novel "we" hypothesis in which shared representations, rather than self-other distinctions, shape the mind for a subgroup of mourners with complicated grief. Recognition of "we-experiences" in mourning can enhance grief theory, research, and practice.

Oxytocin blurs the self-other distinction implicitly but not explicitly

Previous research has shown an inconsistent pattern of how oxytocin (OT) affects the distinction between self and others: whereas one line of studies has revealed that OT blurs the self-other distinction, other studies have not. In an attempt to solve these inconsistencies, we hypothesized that OT blurs the boundary between self and other implicitly but not explicitly. To test this assumption, we used two experimental approaches. After participants intranasally self-administered OT or placebo, they were eye-tracked while conducting a prediction task (Study 1) or they were video-recorded while conducting a distraction task with a human counterpart (Study 2). The findings confirmed the hypothesis. People usually show a distinct eye movement pattern when making self and other predictions. OT changed this pattern: the eye movement behavior during other predictions approached the eye movement behavior during selfpredictions under OT in Study 1. In Study 2, OT made the participants to mimic their confederates' mannerisms more strongly, displaying a behavioral self-other merge. Importantly, these incidents of self-other blurring only emerged implicitly. In Study 1, conscious likelihood estimates sharply differentiated between other and selfpredictions, and participants in Study 2 were not aware of mimicking the others' behaviors. Thus, a self-other merge did not occur explicitly. These findings provide some insights into recent inconsistencies of OT research and add to the understanding of the nonapeptide itself.

Positive Social Interactions in a Lifespan Perspective with a Focus on Opioidergic and Oxytocinergic Systems: Implications for Neuroprotection

In recent years, a growing interest has emerged in the beneficial effects of positive social interactions on health. The present work aims to review animal and human studies linking social interactions and health throughout the lifespan, with a focus on current knowledge of the possible mediating role of opioids and oxytocin. During the prenatal period, a positive social environment contributes to regulating maternal stress response and protecting the fetus from exposure to maternal active glucocorticoids. Throughout development, positive social contact with the caregiver acts as a “hidden regulator” and promotes infant neuroaffective development. Postnatal social neuroprotection interventions involving caregiver–infant physical contact seem to be crucial for rescuing preterm infants at risk for neurodevelopmental disorders. Attachment figures and friendships in adulthood continue to have a protective role for health and brain functioning, counteracting brain aging. In humans, implementation of meditative practices that promote compassionate motivation and prosocial behavior appears beneficial for health in adolescents and adults. Human and animal studies suggest the oxytocinergic and opioidergic systems are important mediators of the effects of social interactions. However, most of the studies focus on a specific phase of life (i.e., adulthood). Future studies should focus on the role of opioids and oxytocin in positive social interactions adopting a lifespan perspective.

A Neural Model of Empathic States in Attachment-Based Psychotherapy

We build on a neuroanatomical model of how empathic states can motivate caregiving behavior, via empathy circuit-driven activation of regions in the hypothalamus and amygdala, which in turn stimulate a mesolimbic-ventral pallidum pathway, by integrating findings related to the perception of pain in self and others. On this basis, we propose a network to capture states of personal distress and (weak and strong forms of) empathic concern, which are particularly relevant for psychotherapists conducting attachment-based interventions. This model is then extended for the case of self-attachment therapy, in which conceptualized components of the self serve as both the source of and target for empathic resonance. In particular, we consider how states of empathic concern involving an other that is perceived as being closely related to the self might enhance the motivation for self-directed bonding (which in turn is proposed to lead the individual toward more compassionate states) in terms of medial prefrontal cortex-mediated activation of these caregiving pathways. We simulate our model computationally and discuss the interplay between the bonding and empathy protocols of the therapy.

Differential Effects of Oxytocin on Visual Perspective Taking for Men and Women

Although oxytocin (OXT) has been shown to lead to reduced self-orientation, no study to date has directly and effectively weakened the egocentric tendencies in perspective taking tasks for both men and women. In this double-blind, placebo-controlled, mixed design study we investigated the effects of OXT on men and women in visual perspective taking tasks. The results showed that OXT shortened the differences in response time between men and women in all experimental conditions. In addition, after OXT administration, the difference in reaction time between judging from one's own perspective and judging from others' perspectives decreased in female participants; however, this effect was not present in males. This may indicate that under OXT treatment, women have a higher tendency to overcome interference from their position and mindset when judging others' perspectives. However, OXT did not affect participants' accuracy, which is possibility because the used task was not suited to detect performance improvements caused by OXT. In summary, the above results may indicate that OXT could increase perspective-taking abilities through reducing self-bias and increasing the perception of others; furthermore, this trend mainly affected women rather than men.

Working hard for oneself or others: Effects of oxytocin on reward motivation in social anxiety disorder

There is some evidence to suggest that oxytocin promotes social behavior, especially for disorders characterized by social dysfunction, such as social anxiety disorder (SAD). The goal of this study was to examine the effect of oxytocin on reward motivation in SAD. We tested whether oxytocin promotes prosocial, or antisocial, self-directed decisions, and whether its effects depended on social anxiety severity and attachment. Fifty-two males with SAD received 24 international units of oxytocin or placebo, and completed a reward motivation task that measured willingness to work for self vs. other monetary rewards. Although there was no main drug effect, social anxiety severity moderated the effect of oxytocin. Less socially anxious individuals who received oxytocin worked harder for other vs. own rewards, compared to high socially anxious individuals. Attachment did not moderate this effect. Among people with SAD, oxytocin enhances prosocial behaviors in individuals with relatively lower levels of social anxiety. National Institutes of Health ClinicalTrials.gov Registry #NCT01856530. https://clinicaltrials.gov/ct2/show/NCT01856530?term=oxytocin+pro-social&rank=2.

Oxytocin Increases the Perceived Value of Both Self- and Other-Owned Items and Alters Medial Prefrontal Cortex Activity in an Endowment Task

The neuropeptide oxytocin (OXT) can influence self-processing and may help motivate us to value the attributes of others in a more self-like manner by reducing medial prefrontal cortex (mPFC) responses. We do not know however whether this OXT effect extends to possessions. We tend to place a higher monetary value on specific objects that belong to us compared to others, known as the "endowment effect". In two double-blind, between-subject placebo (PLC) controlled experiments in subjects from a collectivist culture, we investigated the influence of intranasal OXT on the endowment effect, with the second study incorporating functional magnetic resonance imaging (fMRI). In the task, subjects decided whether to buy or sell their own or others' (mother/father/classmate/stranger) possessions at various prices. Both experiments demonstrated an endowment effect in the self-owned condition which extended to close others (mother/father) and OXT increased this for self and all other-owned items. This OXT effect was associated with reduced activity in the ventral mPFC (vmPFC) in the self-owned condition but increased in the mother-condition. For the classmate- and stranger-owned conditions OXT increased activity in the dorsal mPFC (dmPFC). Changes in vmPFC activation were associated with the size of the endowment effect for self- and mother-owned items. Functional connectivity between the dmPFC and ventral striatum (VStr) was reduced by OXT in self- and mother-owned conditions and between vmPFC and precuneus in the self-condition. Overall our results show that OXT enhances the endowment effect for both self- and other-owned items in Chinese subjects. This effect is associated with reduced mPFC activation in the self-condition but enhanced activation in all other-conditions and involves differential actions on both dorsal and ventral regions as well as functional connectivity with brain reward and other self-processing regions. Overall our findings suggest that OXT increases the perceived value of both self- and other-owned items by acting on neural circuitry involved in self-processing and reward.

Memory response to oxytocin predicts relationship dissolution over 18 months

BACKGROUND

Oxytocin is known for its role in pair bonding in non-human animals. To examine the role of oxytocin in human romantic bonding, we examined its effect on recall of memories of past and current romantic experiences as predictors of relationship dissolution.

METHOD

In a placebo-controlled, within-subject, randomized experiment, 48 participants (24♀; 16 single) self-administered intranasal oxytocin and completed an autobiographical memory test. Participants in a current romantic relationship reported on their relationship status 18 months later.

RESULTS

Participants in a relationship recalled fewer memories of past romantic partners following oxytocin administration relative to placebo. Participants who responded to oxytocin by recalling more conflict memories of their current romantic partner, relative to placebo, were more likely to have ended their relationship over 18 months than those who did not show this response.

CONCLUSION

These results suggest that the memory response to an intranasal oxytocin challenge may represent an index of relationship outcome over time.

As time goes by: Oxytocin influences the subjective perception of time in a social context

Time perception depends on an event's emotional relevance to the beholder; a subjective time dilation effect is associated with self-relevant, emotionally salient stimuli. Previous studies have revealed that oxytocin modulates the salience of social stimuli and attention to social cues. However, whether the oxytocin system is involved in human subjective time perception is unknown. The aim of the present study was to investigate whether increased oxytocin levels would induce a time dilation effect for self-relevant, positive social cues. In a double-blind, placebo-controlled, between-subject design, heterosexual men were administered intranasal oxytocin or placebo. After about 50min, participants completed a time-bisection task in which they estimated lengths of exposure to happy female faces (self-relevant positive stimuli, based on sexual orientation), emotionally neutral and negative female faces (control), and happy, neutral, and negative male faces (control). Oxytocin induced a subjective time dilation effect for happy female faces and a time compression effect for happy male faces. Our results provide evidence that oxytocin influences time perception, a primary form of human subjectivity.

Oxytocin blurs the self-other distinction during trait judgments and reduces medial prefrontal cortex responses

The neuropeptide oxytocin (OXT) may act either to increase or blur the distinction between self and other and thereby promote either more selfish or altruistic behaviors. To attempt to distinguish between these two possibilities we performed a double-blind, between-subject, placebo-controlled design study to investigate the effect of intranasal OXT on self and other (mother, classmate, or stranger) trait judgments in conjunction with functional magnetic resonance imaging. Results showed that OXT reduced response times for making both self and other judgments, but also reduced the accuracy of their subsequent recall, thereby abolishing the normal self-bias observed in this task. OXT also abolished the positive correlation between response and self-esteem scale scores seen in the PLC group, suggesting that its effects were strongest in individuals with higher levels of self-esteem. A whole-brain functional magnetic resonance imaging analysis revealed that OXT also reduced responses during both self and other trait judgments in the dorsal (dmPFC) and ventral (vmPFC) medial prefrontal cortex. A subsequent region of interest analysis revealed that behavioral performance and self-esteem scale scores were associated with dmPFC activation and its functional connectivity with the anterior cingulate and between the vmPFC and posterior cingulate. Thus overall, while OXT may improve speed of decision making in self -vs. other trait judgments it also blunts the normal bias towards remembering self-attributes and reduces mPFC responses and connectivity with other cortical midline regions involved in self-processing. This is consistent with the view that OXT can reduce self-centered behavior. Hum Brain Mapp 37:2512-2527, 2016. © 2016 Wiley Periodicals, Inc.

Dissecting the Role of Oxytocin in the Formation and Loss of Social Relationships

Current concepts of human sociality highlight a fundamental role of the hypothalamic peptide oxytocin (OXT) in the formation and maintenance of social relationships. However, emerging evidence indicates that OXT does not invariably facilitate social bonding but also produces nonprosocial effects that may have evolved to promote offspring survival. From a mechanistic perspective, we hypothesize that OXT modulates interoceptive signals and self-referential processing, which may result in various social outcomes depending on context- and person-dependent variables such as early-life adversity. Based on this theoretical framework, we discuss translational implications for clinical trials and identify open questions for future research. Specifically, we propose that disrupted OXT signaling due to the loss of affectionate bonds may contribute to emotional disequilibrium and confer elevated risk for the onset of stress-related disorders.

Oxytocin for Male Subjects with Autism Spectrum Disorder and Comorbid Intellectual Disabilities: A Randomized Pilot Study

Approximately half of autism spectrum disorder (ASD) individuals suffer from comorbid intellectual disabilities (IDs). Oxytocin (OXT) receptors are highly expressed in temporal lobe structures and are likely to play a modulatory role in excitatory/inhibitory balance, at least based on animal model findings. Thus, it is feasible that in the highly representative group of Kanner-type ASD subjects, OXT could have a beneficial effect on social communication and social interaction. The aim of this pilot study is to investigate the feasibility and adverse events, such as epilepsy, of the long-term administration of intranasal OXT for adolescent and adult ASD subjects with ID because such patients frequently have seizures. We also addressed the question on how to scale the OXT effects to the core symptoms of social deficits because of the relative difficulty in obtaining objective measurements. Twenty-nine males (aged 15-40 years old) participated in a randomized, double-blind, and placebo-controlled crossover study (each for 8 weeks) with OXT (16 IU/day). Except for seizures experienced by one participant, other serious adverse events did not occur. The primary and secondary outcomes measured using the Childhood Autism Rating Scale and several standard scales, respectively, revealed no difference between the OXT and placebo groups. Instead, in an exploratory analysis, the social interactions observed in the play sessions or in daily life were significantly more frequent in the initial half period in the OXT-first arm of the crossover trial. There were also significant correlations between the plasma OXT concentration and subscale scores for irritability on the Aberrant Behavior Checklist. In conclusion, this pilot study demonstrates that long-term administration of intranasal OXT is tolerable in a representative cohort of ASD individuals with ID and suggests that future multicenter trials of OXT are warranted and should include measurements of reciprocal social interactions based on daily life under closer surveillance for epilepsy.

TRIAL REGISTRATION

UMIN000007250.

Oxytocin reduces neural activity in the pain circuitry when seeing pain in others

Our empathetic abilities allow us to feel the pain of others. This phenomenon of vicarious feeling arises because the neural circuitry of feeling pain and seeing pain in others is shared. The neuropeptide oxytocin (OXT) is considered a robust facilitator of empathy, as intranasal OXT studies have repeatedly been shown to improve cognitive empathy (e.g. mind reading and emotion recognition). However, OXT has not yet been shown to increase neural empathic responses to pain in others, a core aspect of affective empathy. Effects of OXT on empathy for pain are difficult to predict, because OXT evidently has pain-reducing properties. Accordingly, OXT might paradoxically decrease empathy for pain. Here, using functional neuroimaging we show robust activation in the neural circuitry of pain (insula and sensorimotor regions) when subjects observe pain in others. Crucially, this empathy-related activation in the neural circuitry of pain is strongly reduced after intranasal OXT, specifically in the left insula. OXT on the basis of our neuroimaging data thus remarkably decreases empathy for pain, but further research including behavioral measures is necessary to draw definite conclusions.

The oxytocin receptor gene and social perception

Social perception is an important prerequisite for successful social interaction, because it helps to gain information about behaviors, thoughts, and feelings of interaction partners. Previous pharmacological studies have emphasized the relevance of the oxytocin system for social perception abilities, while knowledge on genetic contributions is still scarce. In the endeavor to fill this gap in the literature, the current study searches for associations between participants' social perception abilities as measured by the interpersonal perception task (IPT) and the rs2268498 polymorphism on the OXTR-gene, which has repeatedly been linked to processes relevant to social functioning. N = 105 healthy participants were experimentally tested with the IPT and genotyped for the rs2268498 polymorphism. T-allele carriers (TT and TC genotypes) exhibited significantly better performance in the IPT than carriers of the CC-genotype. This difference was also significant for the subscales measuring the strength of social bonding (kinship and intimacy). As in previous studies, T-allele carriers exhibited better performance in measures of social processing indicating that the rs2268498 polymorphism is an important candidate for understanding the genetic basis of social functioning.

The influence of Oxytocin on automatic motor simulation

Motor simulation is important for imitation, action understanding, and a wide range of social cognitive skills. Furthermore, the neuropeptide hormone Oxytocin (OT) has also been related to social information processing in humans, improving perception of social stimuli and increasing altruism and trust. Surprisingly, however, a direct link between OT and motor simulation has never been systematically investigated. The current study examined this question using the imitation-inhibition task, a paradigm used to investigate automatic imitation behaviour and motor simulation. In this task, participants carry out simple finger movements while observing irrelevant movements that either match (congruent condition) or do not match (incongruent condition) the instructed movements. In a double-blind, placebo-controlled design, male participants were administered either OT (N=24) or placebo (N=24), and subsequently performed the imitation-inhibition task. To ensure specificity of OT effects to imitative behaviour, participants additionally performed a Stroop colour-word interference task (adapted to optimize similarities with the imitation inhibition task) to rule out general effects on cognitive control. As predicted, OT selectively influenced the congruency effect in the imitation-inhibition task but not the congruency effect in the Stroop task. This effect showed that OT led to a larger congruency effect by slowing down reaction times on incongruent trials when observed and own actions did not match. The findings suggest that OT leads to a decrease of control over automatic imitative behaviour mediated by increased self-other merging. Thus, for the first time, a link between OT and motor simulation is demonstrated, providing a window into the role of OT in motoric aspects of social cognition.

Autism, oxytocin and interoception

Autism is a pervasive developmental disorder characterized by profound social and verbal communication deficits, stereotypical motor behaviors, restricted interests, and cognitive abnormalities. Autism affects approximately 1% of children in developing countries. Given this prevalence, identifying risk factors and therapeutic interventions are pressing objectives—objectives that rest on neurobiologically grounded and psychologically informed theories about the underlying pathophysiology. In this article, we review the evidence that autism could result from a dysfunctional oxytocin system early in life. As a mediator of successful procreation, not only in the reproductive system, but also in the brain, oxytocin plays a crucial role in sculpting socio-sexual behavior. Formulated within a (Bayesian) predictive coding framework, we propose that oxytocin encodes the saliency or precision of interoceptive signals and enables the neuronal plasticity necessary for acquiring a generative model of the emotional and social 'self.' An aberrant oxytocin system in infancy could therefore help explain the marked deficits in language and social communication—as well as the sensory, autonomic, motor, behavioral, and cognitive abnormalities—seen in autism.

Intranasal oxytocin enhances positive self-attribution in healthy men

OBJECTIVE

A growing body of studies consistently demonstrates that social responsiveness toward others is influenced by the neurohormone oxytocin. However, the potential role of oxytocin for self-perception remains relatively unexplored. Thus, we investigated whether oxytocin administration influences the self-attribution of positive and negative adjectives at the early, effortful stage of self-related information processing.

METHODS

Sixty healthy male participants received either 24I.U. oxytocin or a placebo in a randomized double-blind study before completing a sorting task, in which they were instructed to co-classify, as fast as possible, positive and negative adjectives into either self or non-self categories.

RESULTS

Oxytocin-treated participants reported stronger positive attitudes toward themselves compared to placebo.

CONCLUSIONS

The present findings demonstrate that oxytocin administration influences the early stage of self-related information processing and suggests that the oxytocinergic system might be involved in psychopathological conditions characterized by a negative representation of self.

Approaching the biology of human parental attachment: brain imaging, oxytocin and coordinated assessments of mothers and fathers

Brain networks that govern parental response to infant signals have been studied with imaging techniques over the last 15 years. The complex interaction of thoughts and behaviors required for sensitive parenting enables the formation of each individual's first social bonds and critically shapes development. This review concentrates on magnetic resonance imaging experiments which directly examine the brain systems involved in parental responses to infant cues. First, we introduce themes in the literature on parental brain circuits studied to date. Next, we present a thorough chronological review of state-of-the-art fMRI studies that probe the parental brain with a range of baby audio and visual stimuli. We also highlight the putative role of oxytocin and effects of psychopathology, as well as the most recent work on the paternal brain. Taken together, a new model emerges in which we propose that cortico-limbic networks interact to support parental brain responses to infants. These include circuitry for arousal/salience/motivation/reward, reflexive/instrumental caring, emotion response/regulation and integrative/complex cognitive processing. Maternal sensitivity and the quality of caregiving behavior are likely determined by the responsiveness of these circuits during early parent-infant experiences. The function of these circuits is modifiable by current and early-life experiences, hormonal and other factors. Severe deviation from the range of normal function in these systems is particularly associated with (maternal) mental illnesses - commonly, depression and anxiety, but also schizophrenia and bipolar disorder. Finally, we discuss the limits and extent to which brain imaging may broaden our understanding of the parental brain given our current model. Developments in the understanding of the parental brain may have profound implications for long-term outcomes in families across risk, resilience and possible interventions. This article is part of a Special Issue entitled Oxytocin and Social Behav.

Oxytocin increases the likeability of physically formidable men

Physical size and strength are associated with dominance and threat. The current study tested (i) whether men's evaluations of male strangers would be negatively influenced by cues indicating physical formidability, and (ii) whether these evaluations would be influenced by oxytocin, a neuropeptide that mediates social behavior and reduces social anxiety. In a placebo-controlled double-blind design, we administered either oxytocin (24 I.U.) or placebo intranasally to 100 healthy males and assessed their responses to an image of either a physically formidable (strong) or physically non-formidable (weak) male peer. Whereas participants receiving placebo expressed dislike and avoidance of the strong male relative to the weak male, oxytocin selectively improved social evaluation of the strong male. These results provide first evidence that oxytocin regulates social evaluation of peers based on body features indicating strength and formidability. We discuss the possibility that oxytocin may promote the expansion of social networks by increasing openness toward potentially threatening individuals.

Oxytocin increases empathy to pain when adopting the other- but not the self-perspective

There is growing evidence that the neuropeptide oxytocin (OT) facilitates various forms of sensitivity to others, but the mechanism by which OT enhances empathy in humans is unclear. In this study, we examined whether OT increases empathy by the way of blurring the distinction between self and other, or by enhancing the difference between self and other. In this double-blind, placebo-controlled, within-subject crossover design, empathic responses of healthy participants were compared when imagining oneself (i.e., self-perspective empathy) versus when imagining the other (i.e., other-perspective empathy) in painful and nonpainful situations. Under OT treatment, participants expressed more empathy when imagining others than when imagining oneself in pain. This was in contrast to the placebo condition where there were no differences between the empathic responses during the self- and the other-perspective. We propose that the modulatory effect of OT on empathy when taking the other-perspective may be mediated by its role in self- and other-distinctiveness and corollary by its role in increasing salience to social agents and cues.

Opposing effects of oxytocin on moral judgment in males and females

Current perspectives on the evolutionary roots of human morality suggest it arose to incentivize social cooperation by promoting feelings of disgust toward selfish behavior, although the underlying neural mechanisms remain unclear. To investigate whether the ancient mammalian neuropeptide oxytocin (OXT) influences self-referential processing in the domains of emotion evaluation and moral decision making, we conducted a pharmaco-functional magnetic resonance imaging (fMRI) and a behavioral experiment involving 157 healthy women and men who were treated with either OXT (24 IU) or placebo (PLC) intranasally. Our results show that OXT facilitated cortical midline responses during self-processing of disgust and selectively promoted self-interest moral judgments in men. In contrast, in women OXT increased the reaction time difference between accepted and rejected moral dilemmas and led them to suppress their self-interest and respond more altruistically for the benefit of others. Taken together, these findings suggest an OXT-related sexual dimorphism in human moral behavior which evolved adaptively to optimize both protection and nurturing of offspring by promoting selfish behavior in men and altruistic behavior in women.

Is stress affecting our ability to tune into others? Evidence for gender differences in the effects of stress on self-other distinction

Stress is a ubiquitous challenge in society as we consistently interact with others under the influence of stress. Distinguishing self- from other-related mental representations plays an important role for social interactions, and is a prerequisite for crucial social skills such as action understanding, empathy, and mentalizing. Little is known, however, about the effects of stress on self-other distinction. We assessed how acute stress impacts self-other distinction in the perceptual-motor, the affective, and the cognitive domain, in a male and female sample. In all domains, the results show opposing effects of stress on the two genders: while women showed increases in self-other distinction, men showed decreases. Our findings suggest that women flexibly disambiguate self and other under stress, enabling accurate social responses, while men respond with increased egocentricity and less adaptive regulation. This has crucial implications for explaining gender differences in social skills such as empathy and prosociality.