Neurophysiological effects of acute oxytocin administration: systematic review and meta-analysis of placebo-controlled imaging studies

Social functioning predicts individual changes in EEG microstates following intranasal oxytocin administration: A double-blind, cross-over randomized clinical trial

Oxytocin (OXT) modulates social behaviors. However, the administration of exogenous OXT in humans produces inconsistent behavioral changes, affecting future consideration of OXT as a treatment for autism and other disorders with social symptoms. Inter-individual variability in social functioning traits might play a key role in how OXT changes brain activity and, therefore, behavior. Here, we investigated if inter-individual variability might dictate how single-dose intranasal OXT administration (IN-OXT) changes spontaneous neural activity during the eyes-open resting state. We used a double-blinded, randomized, placebo-controlled, cross-over design on 30 typically developing young adult men to investigate the dynamics of EEG microstates corresponding to activity in defined neural networks. We confirmed previous reports that, at the group level, IN-OXT increases the representation of the attention and salience microstates. Furthermore, we identified a decreased representation of microstates associated with the default mode network. Using multivariate partial least square statistical analysis, we found that social functioning traits associated with IN-OXT-induced changes in microstate dynamics in specific spectral bands. Correlation analysis further revealed that the higher the social functioning, the more IN-OXT increased the appearance of the visual network-associated microstate, and suppressed the appearance of a default mode network-related microstate. The lower the social functioning, the more IN-OXT increases the appearance of the salience microstate. The effects we report on the salience microstate support the hypothesis that OXT regulates behavior by enhancing social salience. Moreover, our findings indicate that social functioning traits modulate responses to IN-OXT and could partially explain the inconsistent reports on IN-OXT effects.

Oxytocin and social learning in socially anxious men and women

OBJECTIVE

This study extended a classic self-referential learning paradigm by investigating the effects of intranasally-administered oxytocin in high and low socially anxious participants during social learning, as a function of social anxiety levels and sex.

METHODS

In a randomized double-blinded design, 160 participants were either given intranasal oxytocin (24 I.U.) or placebo. Subsequently, while lying in an MR scanner, participants were shown neutral faces that were paired with positively, neutrally, or negatively valenced self-referential sentences, during which we measured self-reported arousal and sympathy of the facial stimuli, pupil dilation, and changes in the brain-oxygen-level dependent signal. Four-factor mixed analyses of variance with the between-subjects factors group (high socially anxious vs. low socially anxious), substance (oxytocin vs. placebo), and sex (male vs. female) and the within-subjects factor sentence valence (positive vs. neutral vs. negative) were conducted for each measure, respectively.

RESULTS

Administration of intranasal oxytocin yielded an increase in sympathy ratings in high socially anxious compared to low socially anxious individuals and decreased arousal ratings for positively-conditioned faces in low socially anxious participants. As an objective physiological measure of arousal, pupil dilation mirrored the behavioral results. Oxytocin effects on neural activation in the insula interacted with anxiety levels and sex: low socially anxious individuals yielded lower activation under oxytocin than placebo; the converse was observed in high socially anxious individuals. This interaction also differed between sexes, as men yielded higher activation levels than women. These findings were more prominent for positively- and negatively-conditioned faces. Within the amygdala, high socially anxious men yielded higher activation than high socially anxious women in the left hemisphere, and low socially anxious men yielded higher activation than low socially anxious women from positively- and negatively-conditioned faces, though no influence of oxytocin was detected.

CONCLUSION

These results suggest oxytocin-induced behavioral, physiological, and neural changes as a function of social learning in socially low and high anxious individuals. These findings challenge the amygdalocentric view of the role of emotions in social learning, instead contributing to the growing body of findings implicating the insula therein, revealing an interaction between oxytocin, sex, and emotional valence. Such discoveries raise an interesting set of questions regarding the computational goals of regions such as the insula in emotional learning and how neural activity can play a diagnostic or prognostic role in social anxiety, potentially leading to new treatment opportunities that may combine oxytocin and neurofeedback differentially for men and women.

Oral oxytocin blurs sex differences in amygdala responses to emotional scenes

BACKGROUND

The sex differences were co-shaped by innate biological differences and social environment, and were frequently observed in human emotional neural responses. Oral administration of oxytocin, as an alternative and noninvasive intake method, has been demonstrated to produce sex-dependent effects on emotional face processing. However, it is unclear whether oral oxytocin produces similar sex-dependent effects on processing continuous emotional scenes.

METHODS

Current randomized, double-blind, placebo-controlled neuro-psychopharmacological fMRI experiment was conducted in 147 healthy participants (oxytocin=74, male/female=37/37; placebo=73, male/female=36/37) to examine the oral oxytocin effect on plasma oxytocin concentrations and neural response to emotional scenes in both sexes.

RESULTS

At the neuroendocrine level, females showed lower endogenous oxytocin concentrations than males, but oral oxytocin equally increased the oxytocin concentrations in both sexes. Regarding neural activity, emotional scenes evoked opposite valence-independent effects on right amygdala activation (females>males) and its functional connectivity with the insula (males>females) in two sexes in the placebo group. This sex difference were either attenuated (amygdala response) or even completely eliminated (amygdala-insula functional connectivity) in the oxytocin group. The multivariate pattern analysis confirmed these findings by developing an accurate sex-predictive neural pattern that including the amygdala and the insula under the placebo but not oxytocin condition.

CONCLUSION

Present study suggests a pronounced sex-difference in neural responses to emotional scenes which is abolished by oral oxytocin, with it having opposite modulatory effects in two sexes. Possibly this may reflect oral OXT enhancing emotional regulation to continuous emotional stimuli in both sexes by facilitating appropriate changes in sex-specific amygdala-insula circuitry.

Cognition and psychological wellbeing in hypopituitary patients

Hypopituitarism (HP) frequently occurs in patients presenting with sellar masses and despite recent advances in therapeutic options, HP patients consistently suffer from impaired quality of life due to psychological distress and cognitive dysfunction. These neurocognitive complications tend to persist in spite of surgical or biochemical remission of the disease making it especially challenging to segregate the effect of HP per se from other comorbidities such as the effect of tumour, surgery, radiation therapy, or complications caused by excess hormone production. Regardless, there is ample evidence to suggest that receptors for various pituitary hormones are abundantly expressed in key areas of central nervous system that are associated with memory and behaviour function and HP is also associated with poor sleep which can further exacerbate neurocognitive dysfunction. There is also evidence that hormonal replacement in HP patients partially restores these neurocognitive functions and improves sleep disorders. However, there is a need for creating better awareness among healthcare providers interacting with HP patients to enhance an earlier recognition of these disorder and their impact on quality of life despite initial remission. Importantly, there is a need to not only develop better and more cost-effective replacement therapies that would closely mimic the physiological hormonal release patterns, but also develop coping strategies for HP patients suffering from these complications.

Chronic oxytocin improves neural decoupling at rest in children with autism: an exploratory RCT

BACKGROUND

Shifts in peak frequencies of oscillatory neural rhythms are put forward as a principal mechanism by which cross-frequency coupling/decoupling is implemented in the brain. During active neural processing, functional integration is facilitated through transitory formations of "harmonic" cross-frequency couplings, whereas "nonharmonic" decoupling among neural oscillatory rhythms is postulated to characterize the resting, default state of the brain, minimizing the occurrence of spurious, noisy, background couplings.

METHODS

Within this exploratory, randomized, placebo-controlled trial, we assessed whether the transient occurrence of nonharmonic and harmonic relationships between peak-frequencies in the alpha (8-14 Hz) and theta (4-8 Hz) bands is impacted by intranasal administration of oxytocin, a neuromodulator implicated in improving homeostasis and reducing stress/anxiety. To do so, resting-state electroencephalography was acquired before and after 4 weeks of oxytocin administration (12 IU twice-daily) in children with autism spectrum disorder (8-12 years, n = 33 oxytocin; n = 34 placebo). At the baseline, neural assessments of children with autism were compared with those of a matched cohort of children without autism (n = 40).

RESULTS

Compared to nonautistic peers, autistic children displayed a lower incidence of nonharmonic alpha-theta cross-frequency decoupling, indicating a higher incidence of spurious "noisy" coupling in their resting brain (p = .001). Dimensionally, increased neural coupling was associated with more social difficulties (p = .002) and lower activity of the parasympathetic "rest & digest" branch of the autonomic nervous system (p = .018), indexed with high-frequency heart-rate-variability. Notably, after oxytocin administration, the transient formation of nonharmonic cross-frequency configurations was increased in the cohort of autistic children (p < .001), indicating a beneficial effect of oxytocin on reducing spurious cross-frequency-interactions. Furthermore, parallel epigenetics changes of the oxytocin receptor gene indicated that the neural effects were likely mediated by changes in endogenous oxytocinergic signaling (p = .006).

CONCLUSIONS

Chronic oxytocin induced important homeostatic changes in the resting-state intrinsic neural frequency architecture, reflective of reduced noisy oscillatory couplings and improved signal-to-noise properties.

An Umbrella Review of the Fusion of fMRI and AI in Autism

The role of functional magnetic resonance imaging (fMRI) is assuming an increasingly central role in autism diagnosis. The integration of Artificial Intelligence (AI) into the realm of applications further contributes to its development. This study's objective is to analyze emerging themes in this domain through an umbrella review, encompassing systematic reviews. The research methodology was based on a structured process for conducting a literature narrative review, using an umbrella review in PubMed and Scopus. Rigorous criteria, a standard checklist, and a qualification process were meticulously applied. The findings include 20 systematic reviews that underscore key themes in autism research, particularly emphasizing the significance of technological integration, including the pivotal roles of fMRI and AI. This study also highlights the enigmatic role of oxytocin. While acknowledging the immense potential in this field, the outcome does not evade acknowledging the significant challenges and limitations. Intriguingly, there is a growing emphasis on research and innovation in AI, whereas aspects related to the integration of healthcare processes, such as regulation, acceptance, informed consent, and data security, receive comparatively less attention. Additionally, the integration of these findings into Personalized Medicine (PM) represents a promising yet relatively unexplored area within autism research. This study concludes by encouraging scholars to focus on the critical themes of health domain integration, vital for the routine implementation of these applications.

At the Head and Heart of Oxytocin's Stress-Regulatory Neural and Cardiac Effects: A Chronic Administration RCT in Children with Autism

INTRODUCTION

Intranasal administration of oxytocin presents a promising new approach to reduce disability associated with an autism spectrum disorder diagnosis. Previous investigations have emphasized the amygdala as the neural foundation for oxytocin's acute effects. However, to fully understand oxytocin's therapeutic potential, it is crucial to gain insight into the neuroplastic changes in amygdala circuitry induced from chronic oxytocin administrations, particularly in pediatric populations.

OBJECTIVE

We aimed to examine the impact of a 4-week course of intranasal oxytocin on amygdala functional connectivity in children with autism, compared to placebo. Additionally, we investigated whether oxytocin improves cardiac autonomic arousal, as indexed by high-frequency heart rate variability.

METHODS

Fifty-seven children with autism aged 8-12 years (45 boys, 12 girls) participated in a double-blind, randomized pharmaco-neuroimaging trial involving twice-daily administrations of intranasal oxytocin or placebo. Resting-state fMRI scans and simultaneous, in-scanner heart rate recordings were obtained before, immediately after, and 4 weeks after the nasal spray administration period.

RESULTS

Significant reductions in intrinsic amygdala-orbitofrontal connectivity were observed, particularly at the 4-week follow-up session. These reductions were correlated with improved social symptoms and lower cardiac autonomic arousal. Further, oxytocin's neural and cardiac autonomic effects were modulated by epigenetic modifications of the oxytocin receptor gene. The effects were more pronounced in children with reduced epigenetic methylation, signifying heightened expression of the oxytocin receptor.

CONCLUSION

These findings underscore that a 4-week oxytocin administration course decreases amygdala connectivity and improves cardiac autonomic balance. Epigenetic modulators may explain inter-individual variation in responses to oxytocin.

The effect of intranasal oxytocin on social reward processing in humans: a systematic review

Understanding the neurobiology of social reward processing is fundamental, holding promises for reducing maladaptive/dysfunctional social behaviors and boosting the benefits associated with a healthy social life. Current research shows that processing of social (vs. non-social) rewards may be driven by oxytocinergic signaling. However, studies in humans often led to mixed results. This review aimed to systematically summarize available experimental results that assessed the modulation of social reward processing by intranasal oxytocin (IN-OXY) administration in humans. The literature search yielded 385 results, of which 19 studies were included in the qualitative synthesis. The effects of IN-OXY on subjective, behavioral, and (neuro)physiological output variables are discussed in relation to moderating variables-reward phase, reward type, onset and dosage, participants' sex/gender, and clinical condition. Results indicate that IN-OXY is mostly effective during the consumption ("liking") of social rewards. These effects are likely exerted by modulating the activity of the prefrontal cortex, insula, precuneus, anterior cingulate cortex, amygdala, and striatum. Finally, we provide suggestions for designing future oxytocin studies.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021278945, identifier CRD42021278945.

The neural effects of oxytocin administration in autism spectrum disorders studied by fMRI: A systematic review

PURPOSE

Oxytocin (OXT) is a hypothalamic neuropeptide that is released from the posterior pituitary gland and at specific targets in the central nervous system (CNS). The prosocial effects of OXT acting in the CNS present it as a potential therapeutic agent for the treatment of aspects of autism spectrum disorder (ASD). In this article, we systematically review the functional MRI (fMRI) literature that reports task-state and resting-state fMRI (rsfMRI) studies of the neural effects of single or multiple dose intranasal OXT (IN-OXT) administration in individuals with ASD.

METHOD

We searched four databases for relevant documents (PubMed, Web of Science, Scopus, and Google Scholar) using the keywords "autism spectrum disorder", "Asperger Syndrome", "oxytocin", and "fMRI". Moreover, we made a manual search to assess the quality of our automatic search. The search was confined to English language articles published in the interval February 2013 until March 2021.

RESULTS

The search yielded 12 fMRI studies with OXT intervention, including 288 individuals with ASD (age 8-55 years) enrolled in randomized, double-blind, placebo-controlled, parallel designs, within-subject-crossover experimental OXT trials. Studies reporting activation task and rsfMRI were summarized with region of interest (ROI) or whole-brain voxel wise analysis. The systematic review of the 12 studies supported the proposition that IN-OXT administration alters brain activation in individuals with ASD. The effects of IN-OXT interacted with the type of the task and the overall results did not indicate restoration of normal brain activation in ASD signature regions albeit the lack of statistical evidence.

CONCLUSION

A large body of evidence consistently indicates that OXT alters activation to fMRI in brain networks of individuals with ASD, but with uncertain implications for alleviation of their social deficits.

Neuroimaging oxytocin modulation of social reward learning in schizophrenia

BACKGROUND

Conventional pharmacological approaches have limited effectiveness for schizophrenia. There is interest in the application of oxytocin, which is involved in social cognition. Clinical trials have yielded mixed results, with a gap in understanding neural mechanisms.

AIMS

To evaluate the behavioural impact of oxytocin administration on a social learning task in individuals with schizophrenia, and elucidate any differential neural activity produced.

METHOD

We recruited 20 clinically stable right-handed men diagnosed with schizophrenia or schizoaffective disorder. In a double-blind cross-over randomised controlled study, 40 IU of oxytocin or placebo were administered before functional magnetic resonance imaging of participants playing a multi-round economic exchange game of trust. Participants had the role of investors (investment trials) receiving repayment on their investments (repayment trials), playing one session against a computer and a second against a player believed to be human.

RESULTS

During investment trials, oxytocin increased neural signalling in the right lateral parietal cortex for both human and computer player trials, and attenuated signalling in the right insula for human player trials. For repayment trials, oxytocin elicited signal increases in left insula and left ventral caudate, and a signal decrease in right amygdala during the human player trials; conversely it resulted in right dorsal caudate activation during the computer player trials. We did not find a significant change in behavioural performance associated with oxytocin administration, or any associations with symptoms.

CONCLUSIONS

During a social learning task oxytocin modulates cortical and limbic substrates of the reward-processing network. These perturbations can be putatively linked to the pathoaetiology of schizophrenia.

Effects of single- and multiple-dose oxytocin treatment on amygdala low-frequency BOLD fluctuations and BOLD spectral dynamics in autism

Prior neuroimaging clinical trials investigating the neural effects of intranasal administration of the neuropeptide oxytocin demonstrated a key role of the amygdala in oxytocin's neuromodulatory effects. These studies mostly demonstrated the acute effects of single-dose administrations, examining task-dependent effects of oxytocin on brain activity elicited during explicit experimental tasks or stimuli presentations. The increased consideration of oxytocin as a potential ameliorating treatment in autism spectrum disorder (ASD) requires a better understanding of how multiple-dose oxytocin administration affects intrinsic, task-free, amygdala function. In this double-blind, randomized, placebo-controlled trial with between-subject design, 38 adult men with ASD underwent resting-state fMRI scanning before and after oxytocin or placebo treatment. Effects were assessed either after a single-dose administration, consisting of 24 international units, or after multiple-dose treatment, consisting of 4 weeks of once-daily nasal spray administrations. Compared to placebo, oxytocin induced a decrease in intrinsic resting-state BOLD signal amplitudes of the bilateral amygdala (fractional amplitudes of low-frequency fluctuations) and modulated cross-frequency interactions between adjacent BOLD frequency components. The right amygdala showed a pattern of reduced cross-frequency harmonicity, while the left amygdala showed a relative increase in harmonic cross-frequency interactions after oxytocin treatment. Notably, the direction and magnitude of BOLD spectral changes induced after a single-dose were qualitatively similar to treatment effects induced after multiple-dose treatment. Furthermore, the identified spectral changes in amygdalar BOLD amplitude and cross-frequency harmonicity were associated with improved feelings of tension, reflecting oxytocin's anxiolytic, stress-reducing neuromodulatory role. The observed effects of oxytocin on amygdalar BOLD spectral characteristics and associated behaviors contribute to a deeper mechanistic understanding of the intrinsic, task-free neuromodulatory dynamics that underlie single- and multiple-dose oxytocin treatment in ASD. European Clinical Trial Registry (Eudract 2014-000586-45).

Oxytocin promotes species-relevant outgroup attention in bonobos and chimpanzees

Previous research has found that oxytocin (OT) is associated with intergroup behaviour in humans as well as wild chimpanzees, and that exogenous OT affects Pan social attention. The two Pan species, bonobos and chimpanzees, differ drastically from one another in their intensity of intergroup competition, with lethal intergroup aggression often led by males in chimpanzees and more tolerant associations often centered around females in bonobos. However, it remains unclear how exogenous OT changes the two species' responses to ingroup and outgroup individuals. In this study, after intranasal administration of nebulized OT or placebo control, chimpanzees and bonobos viewed image pairs of ingroup and outgroup conspecifics while their eye movements were tracked with an eye-tracker. Although the overall effect of OT was small, we found that OT shifted bonobos' and chimpanzees' attention to outgroup images of the sex primarily involved in intergroup encounters in each species. Specifically, OT selectively shifted attention towards outgroup photos of female conspecifics in bonobos, and those of outgroup male conspecifics in chimpanzees. This suggests that OT generally promotes outgroup attention in both bonobos and chimpanzees but this effect is restricted to the sex most relevant in intergroup relations. These results suggest that, although OT may have a generally conserved role in hominid intergroup behaviour, it may act in species-relevant ways under the influence of their socio-ecological backgrounds.

Effect of Intranasal Oxytocin on Resting-state Effective Connectivity in Schizophrenia

OBJECTIVES

Evidence from several lines of research suggests the critical role of neuropeptide oxytocin in social cognition and social behavior. Though a few studies have examined the effect of oxytocin on clinical symptoms of schizophrenia, the underlying neurobiological changes are underexamined. Hence, in this study, we examined the effect of oxytocin on the brain's effective connectivity in schizophrenia.

METHODS

31 male patients with schizophrenia (SCZ) and 21 healthy male volunteers (HV) underwent resting functional magnetic resonance imaging scans with intra-nasal oxytocin (24 IU) and placebo administered in counterbalanced order. We conducted a whole-brain effective connectivity analysis using a multivariate vector autoregressive granger causality model. We performed a conjunction analysis to control for spurious changes and canonical correlation analysis between changes in connectivity and clinical and demographic variables.

RESULTS

Three connections, sourced from the left caudate survived the FDR correction threshold with the conjunction analysis; connections to the left supplementary motor area, left precentral gyrus, and left frontal inferior triangular gyrus. At baseline, SCZ patients had significantly weaker connectivity from caudate to these three regions. Oxytocin, but not placebo, significantly increased the strength of connectivity in these connections. Better cognitive insight and lower negative symptoms were associated with a greater increase in connectivity with oxytocin.

CONCLUSIONS

These findings provide a preliminary mechanistic understanding of the effect of oxytocin on brain connectivity in schizophrenia. The study findings provide the rationale to examine the potential utility of oxytocin for social cognitive deficits in schizophrenia.

Reduced vagal activity in borderline personality disorder is unaffected by intranasal oxytocin administration, but predicted by the interaction between childhood trauma and attachment insecurity

Individuals with borderline personality disorder (BPD) show self-regulatory deficits, associated with reduced heart-rate variability (HRV). However, results on reduced HRV in BPD remain heterogeneous, thus encouraging the search for developmental constructs explaining this heterogeneity. The present study first examined predictors of reduced resting-state HRV in BPD, namely the interaction between self-reported adult attachment insecurity and childhood trauma. Second, we investigated if alterations in resting-state HRV are modified by intranasal oxytocin administration, as oxytocin may enhance HRV and is implicated in the interaction between childhood trauma and disturbed attachment for the pathogenesis of BPD. In a randomized, placebo-controlled trial, 53 unmedicated women with BPD and 60 healthy controls (HC) self-administered either 24 I.U. of oxytocin or placebo and underwent a 4-min electrocardiogram. Our results replicate significantly reduced HRV in women with BPD, explained up to 16% by variations in childhood trauma and attachment insecurity. At high levels of acute attachment insecurity, higher levels of childhood trauma significantly predicted reduced HRV in BPD. However, our results do not support a significant effect of oxytocin on mean HRV, and no interaction effect emerged including childhood trauma and attachment insecurity. Our findings highlight a complex interaction between reduced vagal activity and developmental factors in BPD.

The importance of pro-social processing, and ameliorating dysfunction in schizophrenia. An FMRI study of oxytocin

Schizophrenia is often a severe and debilitating mental illness, frequently associated with impairments in social cognition that hinder individuals' abilities to relate to others and integrate effectively in society. Oxytocin has emerged as a putative therapeutic agent for treating social deficits in schizophrenia, but the mode of action remains unclear. This placebo-controlled crossover study aimed to elucidate the neural underpinnings of oxytocin administration in patients with schizophrenia. 20 patients with schizophrenia were examined using functional magnetic resonance imaging under oxytocin (40 IU) or placebo nasal spray. Participants performed a stochastically rewarded decision-making task that incorporated elements of social valence provided by different facial expressions, i.e. happy, angry and neutral. Oxytocin attenuated the normal bias in selecting the happy face accompanied by reduced activation in a network of brain regions that support mentalising, processing of facial emotion, salience, aversion, uncertainty and ambiguity in social stimuli, including amygdala, temporo-parietal junction, posterior cingulate cortex, precuneus and insula. These pro-social effects may contribute to the facilitation of social engagement and social interactions in patients with schizophrenia and warrant further investigation in future clinical trials for social cognitive impairments in schizophrenia.

Monitoring the effect of oxytocin on the neural sensitivity to emotional faces via frequency-tagging EEG: A double-blind, cross-over study

The neuropeptide oxytocin (OXT) is suggested to exert an important role in human social behaviors by modulating the salience of social cues. To date, however, there is mixed evidence whether a single dose of OXT can improve the behavioral and neural sensitivity for emotional face processing. To overcome difficulties encountered with classic event-related potential studies assessing stimulus-saliency, we applied frequency-tagging EEG to implicitly assess the effect of a single dose of OXT (24 IU) on the neural sensitivity for positive and negative facial emotions. Neutral faces with different identities were presented at 6 Hz, periodically interleaved with an expressive face (angry, fearful, and happy, in separate sequences) every fifth image (i.e., 1.2 Hz oddball frequency). These distinctive frequency tags for neutral and expressive stimuli allowed direct and objective quantification of the neural expression-categorization responses. The study involved a double-blind, placebo-controlled, cross-over trial with 31 healthy adult men. Contrary to our expectations, we did not find an effect of OXT on facial emotion processing, neither at the neural, nor at the behavioral level. A single dose of OXT did not evoke social enhancement in general, nor did it affect social approach-avoidance tendencies. Possibly ceiling performances in facial emotion processing might have hampered further improvement.

Adult attachment style moderates the effect of oxytocin on neural responses to infant emotional faces

Oxytocin (OT) is known for its positive influence on maternal motivation and behavior, however, the effects of intranasal oxytocin (IN-OT) on neural activity during the perception of infant stimuli are often inconsistent. These discrepancies further reveal the need to take into account individual differences in IN-OT research. The present study aims to examine whether the effects of IN-OT on maternal-related neural responses to infant faces were moderated by participants' attachment style. Using a between-groups, double-blind, placebo-controlled design, 65 nulliparous females were randomly assigned to groups receiving a single dose of 24 IU oxytocin or a placebo via intranasal administration. The neural responses of participants were assessed during a facial recognition task with joy, neutral, and crying infant faces. The results indicated that females with high levels of attachment anxiety exhibited decreased right amygdala activity in response to infant joy faces and decreased bilateral insula activity in response to infant crying faces following IN-OT. Meanwhile, IN-OT enhanced bilateral amygdala and left inferior orbital frontal cortex (OFC) activity in response to infant crying faces in females with high levels of attachment avoidance. In addition, some beneficial effects of IN-OT were also observed in females with low levels of attachment avoidance or anxiety. Our findings demonstrated that the beneficial effects of IN-OT on neural responses to infant faces may depend on individual differences in adult attachment style, thereby contributing to our understanding of the role of OT in maternal caregiving.

Tracking transient changes in the intrinsic neural frequency architecture: Oxytocin facilitates non-harmonic relationships between alpha and theta rhythms in the resting brain

Shifts in the peak frequencies of oscillatory neural rhythms have been put forward as a principal mechanism by which cross-frequency coupling and decoupling is implemented in the brain. This notion is based on the mathematical reality that neural oscillations can only fully synchronize when their peak frequencies form harmonic 2:1 relationships (e.g., f₂=f₁/2). Non-harmonic cross-frequency relationships, on the other hand (based on the irrational golden mean 1.618.:1), provide the highest physiologically possible desynchronized state (reducing the occurrence of spurious, noisy, background coupling), and are therefore anticipated to characterize the resting state of the brain, in which no selective information processing takes place. The present study sought to assess whether the transient occurrence of 1.6:1 non-harmonic and 2:1 harmonic relationships between peak frequencies in the alpha (8-14 Hz) and theta (4-8 Hz) bands - respectively facilitating states of decoupling or coupling between oscillatory rhythms - are impacted by the intranasal administration of a single-dose of oxytocin (OT) or placebo. To do so, continuous resting-state electroencephalography (5 min eyes open, 19 electrodes) was obtained from 96 healthy adult men before and after nasal spray administration. The transient formation of non-harmonic cross-frequency configurations between alpha and theta peak frequencies was significantly increased after OT nasal spray administration, indicating an effect of OT on reducing the intrinsic occurrence of spurious (noisy) background phase synchronizations during resting-state. As a group, the OT group also showed a significant parallel increase in high-frequency and decrease in low-frequency heart rate variability, confirming a homeostatic role of OT in balancing parasympathetic drive. Overall, non-harmonic cross-frequency configurations have been put forward to lay the ground for a healthy neural network allowing the opportunity for an efficient transition from resting state to activity. The observed effects of OT on cross-frequency dynamics are therefore interpreted to reflect a homeostatic role of OT in increasing the signal-to-noise properties of the intrinsic EEG neural frequency architecture, i.e., by precluding the occurrence of 'noisy', unwanted, spurious couplings among neural rhythms in the resting brain.

Oxytocin reduces romantic rejection-induced pain in online speed-dating as revealed by decreased frontal-midline theta oscillations

BACKGROUND

Romantic rejection is an emotionally distressful experience profoundly affecting life, possibly leading to mental illness or suicide. Oxytocin (OT) is a neuropeptide widely implicated in reducing physical pain and negative emotions; however, whether OT has an effect on reducing intense social pain (e.g., romantic rejection) remains unknown. Here, we tested the effect of OT on social pain and investigated its role in the outcome evaluation phase of social decision-making.

METHODS

Electroencephalographic recordings were obtained between August 2nd and October 20th, 2020 in Shenzhen University from 61 healthy participants in a double-blind, placebo-controlled study with a between-subject design. We defined frontal-midline theta oscillation as a neural signature of social pain and assessed self-reported pleasantness ratings for four possible romantic outcomes in an online speed-dating task.

RESULTS

In the placebo group, greater theta power was induced by romantic rejection, being associated with rejection distress. This pattern was not observed in the OT group, where romantic rejection induced significantly decreased theta power compared to the placebo group; in the OT group, there was no association between theta power and rejection distress. Furthermore, the frontal-midline theta oscillation could be source-localized to brain areas overlapping with the physical-social pain matrix (i.e., somatosensory cortex, anterior cingulate cortex, frontal pole, and supplementary motor area).

CONCLUSIONS

OT relieves social pain caused by romantic rejection, reflected in decreased frontal-midline theta oscillations and a diminished connection between theta power and rejection distress. These findings can help understand and harness OT's pain-reducing effect on social pain.

Maternal speech decreases pain scores and increases oxytocin levels in preterm infants during painful procedures

Preterm infants undergo early separation from parents and are exposed to frequent painful clinical procedures, with resultant short- and long-term effects on their neurodevelopment. We aimed to establish whether the mother's voice could provide an effective and safe analgesia for preterm infants and whether endogenous oxytocin (OXT) could be linked to pain modulation. Twenty preterm infants were exposed to three conditions-mother's live voice (speaking or singing) and standard care-in random order during a painful procedure. OXT levels (pg/mL) in saliva and plasma cortisol levels were quantified, and the Premature Infant Pain Profile (PIPP) was blindly coded by trained psychologists. During the mother's live voice, PIPP scores significantly decreased, with a concomitant increase in OXT levels over baseline. The effect on pain perception was marginally significant for singing. No effects on cortisol levels were found. The mother's live voice modulated preterm infants' pain indicators. Endogenous OXT released during vocal contact is a promising protective mechanism during early painful interventions in at-risk populations.

Add-on Oxytocin in the Treatment of Postpartum Acute Schizophrenia: A Case Report

An increasing body of research has been published concerning the potential impact of oxytocin (OT) in the pathophysiology of neuropsychiatric disorders that affect social functioning, such as schizophrenia. The possible therapeutic effect of OT in promoting mother-child bonding could be valuable in the management of postpartum psychosis. Studies on the efficacy of OT as an add-on therapy in the treatment of schizophrenia have found reductions in both positive and negative symptoms. The patient in the case reported here developed her second psychotic episode at the age of 22, a month after delivering her first child. Four weeks after treatment with aripiprazole was initiated, the patient's negative symptoms persisted, causing problems in the mother-child interaction. Intranasal OT (40 IU/d) was then added to the aripiprazole. Assessment scales [the Positive and Negative Syndrome Scale (PANSS), the Disability Assessment Schedule (WHODAS 2.0), and the Barkin Index of Maternal Functioning (BIMF)] and qualitative data from her caregiver were obtained at baseline and in the third and eighth weeks after the end of the OT therapy. Improvement was observed on almost all of the domains of the WHODAS 2.0 and the BIMF, as well as on the PANSS negative and general psychopathology scales. Data from the patient's caregiver indicated an overall improvement in mother-child interaction. These results, especially the improvement in results on the PANSS scale, are similar to findings from previous studies in patients with schizophrenia. OT seems to boost the antipsychotic effect on positive symptoms through the OT dopamine pathway, while the effect on negative symptoms probably involves a more general mechanism. Because the postpartum period is of immense significance for child development and mental well-being, future research to investigate the therapeutic efficacy of OT in the management of postpartum psychosis is warranted.

Randomized clinical trial shows no substantial modulation of empathy-related neural activation by intranasal oxytocin in autism

Evidence suggests that intranasal application of oxytocin facilitates empathy and modulates its underlying neural processes, which are often impaired in individuals with autism spectrum disorders (ASD). Oxytocin has therefore been considered a promising candidate for the treatment of social difficulties in ASD. However, evidence linking oxytocin treatment to social behavior and brain function in ASD is limited and heterogeneous effects might depend on variations in the oxytocin-receptor gene (OXTR). We examined 25 male ASD patients without intellectual disability in a double-blind, cross-over, placebo-controlled fMRI-protocol, in which a single dose of oxytocin or placebo was applied intranasally. Patients performed three experiments in the MRI examining empathy for other's physical pain, basic emotions, and social pain. All participants were genotyped for the rs53576 single-nucleotide polymorphism of the OXTR. Oxytocin increased bilateral amygdala responsiveness during the physical pain task for both painful and neutral stimuli. Other than that, there were no effects of oxytocin treatment. OXTR genotype did not significantly interact with oxytocin treatment. Our results contribute to the growing body of empirical literature suggesting heterogenous effects of oxytocin administration in ASD. To draw clinically relevant conclusions regarding the usefulness of oxytocin treatment, however, empirical studies need to consider methods of delivery, dose, and moderating individual factors more carefully in larger samples.

Effect of oxytocin nasal spray on auditory automatic discrimination measured by mismatch negativity

RATIONALE

As a treatment for cognitive dysfunction in schizophrenia, oxytocin nasal sprays potentially improve social cognition, facial expression recognition, and sense of smell. Mismatch negativity (MMN) is an event-related potential (ERP) reflecting auditory discrimination while MMN deficits reflect cognitive function decline in schizophrenia.

OBJECTIVES

To determine whether oxytocin nasal spray affects auditory MMN METHODS: We measured ERPs in healthy subjects during an auditory oddball task, both before and after oxytocin nasal spray administration. Forty healthy subjects were randomly assigned to either the oxytocin or placebo group. ERPs were recorded during the oddball task for all subjects before and after a 24 international unit (IU) intranasal administration, and MMN was compared between the two groups.

RESULTS

Participants who received oxytocin had significantly shorter MMN latencies than those who received a placebo. Oxytocin had no significant effect on the Change in MMN amplitude.

CONCLUSIONS

The shortened MMN latencies that were observed after oxytocin nasal spray administration suggest that oxytocin may promote the comparison-decision stage.

The effects of emotional stimuli and oxytocin on inhibition ability and response execution in macaque monkeys

Social and emotional content of environmental stimuli influence executive control of behavior. There has been a great variability in the behavioral effects of emotional stimuli in humans. These variabilities might arise from other contextual factors, such as specific task demands or natural hormones, which potentially interact with emotional stimuli in modulating executive functions. This study aimed at examining the effects of social-emotional visual stimuli and a natural hormone (oxytocin) on inhibition ability and response execution of macaque monkeys. In a crossover design, monkeys received inhaled oxytocin or its vehicle before performing a stop-signal task in which they must respond rapidly to a visual go-cue in Go trials but inhibit the initiated response following the onset of a stop-cue in Stop trials. The social-emotional content (negative, positive or neutral) of the go-cue was changed trial-by-trial. We found that monkeys' inhibition ability was significantly influenced by the social-emotional content of stimuli and appeared as an enhanced inhibition ability when monkeys were exposed to negative stimuli. However, response execution was not influenced by the emotional content of stimuli in the current or preceding trials. The same dose of oxytocin, which modulated working memory in monkeys, had no significant effect on the inhibition ability, but significantly decreased monkeys' response time regardless of the stimulus valence. Our findings indicate that emotional stimuli, valence dependently, influence monkeys' inhibition ability but not their response execution and suggest that oxytocin might attenuate reorientation of cognitive resources to the task irrelevant emotional information.

Pharmacotherapy for Frontotemporal Dementia

Frontotemporal dementia is a heterogeneous spectrum of neurodegenerative disorders. The neuropathological inclusions are tau proteins, TAR DNA binding protein 43 kDa-TDP-43, or fused in sarcoma-ubiquitinated inclusions. Genetically, several autosomal mutations account for the heritability of the disorder. Phenotypically, frontotemporal dementia can present with a behavioral variant or a language variant called primary progressive aphasia. To date, there are no approved symptomatic or disease-modifying treatments for frontotemporal dementia. Currently used therapies are supported by low-level of evidence (mostly uncontrolled) studies. The off-label use of drugs is also limited by their side-effect profile including an increased risk of confusion, parkinsonian symptoms, and risk of mortality. Emerging disease-modifying treatments currently target the progranulin and the expansion on chromosome 9 open reading frame 72 genes as well as tau deposits. Advancing our understanding of the pathophysiology of the disease and improving the design of future clinical trials are much needed to optimize the chances to obtain positive outcomes.

Mother brain is wired for social moments

Reorganization of the maternal brain upon childbirth triggers the species-typical maternal social behavior. These brief social moments carry profound effects on the infant's brain and likely have a distinct signature in the maternal brain. Utilizing a double-blind, within-subject oxytocin/placebo administration crossover design, mothers' brain was imaged twice using fMRI while observing three naturalistic maternal-infant contexts in the home ecology; 'unavailable', 'unresponsive', and 'social', when mothers engaged in synchronous peek-a-boo play. The social condition elicited greater neural response across the human caregiving network, including amygdala, VTA, hippocampus, insula, ACC, and temporal cortex. Oxytocin impacted neural response primarily to the social condition and attenuated differences between social and non-social stimuli. Greater temporal consistency emerged in the 'social' condition across the two imaging sessions, particularly in insula, amygdala, and TP. Findings describe how mother's brain varies by caregiving experiences and gives salience to moments of social synchrony that support infant development and brain maturation.

Neurobiobehavioral responses to virtual social rejection in females-exploring the influence of oxytocin

In recent years, especially adolescents and young adults interact frequently via social media and digital communication. Mimicking an online communication platform where participants could initiate short conversations with two computerized interlocutors, the Verbal Interaction Social Threat Task (VISTTA) was used to induce feelings of social rejection. Motivational and physiological reactions were investigated in 43 healthy young women undergoing functional magnetic resonance imaging (fMRI), of which 22 received 24 international units (IU) intranasal oxytocin and 21 received placebo. Replicating previous findings, social rejection entailed a lower willingness to cooperate with the two peers. Increased activation in the anterior cingulate cortex and bilateral insula/inferior frontal gyrus was observed when receiving negative feedback from others, and in the precuneus when subsequently rating one's willingness to cooperate with them in the future. Oxytocin did not seem to alter responses to social rejection. The current findings provide validation of the VISTTA for examining consequences of rejection in a virtual social interaction that bears a strong resemblance to online communication platforms.

Intrinsic, dynamic and effective connectivity among large-scale brain networks modulated by oxytocin

The neuropeptide oxytocin is a key modulator of social-emotional behavior and its intranasal administration can influence the functional connectivity of brain networks involved in the control of attention, emotion and reward reported in humans. However, no studies have systematically investigated the effects of oxytocin on dynamic or directional aspects of functional connectivity. The present study employed a novel computational framework to investigate these latter aspects in 15 oxytocin-sensitive regions using data from randomized placebo-controlled between-subject resting state functional MRI studies incorporating 200 healthy subjects. In order to characterize the temporal dynamics, the 'temporal state' was defined as a temporal segment of the whole functional MRI signal which exhibited a similar functional interaction pattern among brain regions of interest. Results showed that while no significant effects of oxytocin were found on brain temporal state related characteristics (including temporal state switching frequency, probability of transitions between neighboring states, and averaged dwell time on each state) oxytocin extensively (n = 54 links) modulated effective connectivity among the 15 regions. The effects of oxytocin were primarily characterized by increased effective connectivity both between and within emotion, reward, salience, attention and social cognition processing networks and their interactions with the default mode network. Top-down control over emotional processing regions such as the amygdala was particularly affected. Oxytocin also increased effective homotopic interhemispheric connectivity in almost all these regions. Additionally, the effects of oxytocin on effective connectivity were sex-dependent, being more extensive in males. Overall, these findings suggest that modulatory effects of oxytocin on both within- and between-network interactions may underlie its functional influence on social-emotional behaviors, although in a sex-dependent manner. These findings may be of particular relevance to potential therapeutic use of oxytocin in psychiatric disorders associated with social dysfunction, such as autism spectrum disorder and schizophrenia, where directionality of treatment effects on causal interactions between networks may be of key importance .

The Role of Intranasal Oxytocin on Social Cognition: An Integrative Human Lifespan Approach

PURPOSE OF REVIEW

This narrative review synthesizes research from the last two decades on the modulatory role of intranasal OT administration (IN-OT) on social cognition in early life, young/middle adulthood, and older adulthood. Advances and knowledge gaps are identified, and future research directions are discussed within an integrative human lifespan framework to guide novel research on IN-OT and social cognition.

RECENT FINDINGS

Current evidence regarding IN-OT modulation of social-cognitive processes, behavior, and related neurocircuitry is mixed, with some studies suggesting benefits (e.g., improved social perception/interactions, emotion processing) depending on contextual (e.g., social stimuli) and interindividual factors (e.g., age, sex, clinical status). Current research, however, is limited by a focus on isolated life phases, males, and select clinical populations as well as a lack of standardized protocols.

SUMMARY

This literature-based reflection proposes that greater generalizability of findings and scientific advancement on social-cognitive modulation via IN-OT require standardized, multi-method, longitudinal, and cross-sequential assessments in well-powered, well-controlled, and representative samples in line with an integrative lifespan approach, which considers development as a lifelong dynamic process involving both change and stability characterized by the interplay between genetic, neurobiological, and socio-behavioral factors.

Intranasal oxytocin attenuates insula activity in response to dynamic angry faces

The effects of intranasal oxytocin on amygdala activity during emotional perception are often mixed. Given that the brain is organized into networks of interconnected areas, functional connectivity might provide an effective way to further understand the oxytocin effect. The aim of the present study was to investigate whether oxytocin administration affects amygdala activity and its functional connectivity during dynamic facial expression perception. Using a between-group, double-blind, placebo-controlled design, 55 participants were randomly assigned to groups receiving a single dose of 24 IU oxytocin or a placebo via intranasal administration. An implicit emotional task was employed to investigate the effect of oxytocin on neural responses to dynamic angry, neutral, and happy facial expressions with fMRI. Participants were instructed to respond only when the inverted dynamic faces were presented. The results indicated that oxytocin attenuated activation of insula and emotional processing-related regions (e.g., ACC, thalamus, and MFG) during the viewing of dynamic angry faces. However, functional connectivity between the regions involved in the perception of dynamic angry faces was not changed following oxytocin administration. The present findings may contribute to our understanding of the anxiolytic effects of oxytocin and eventually facilitate human clinical applications.

Oxytocin treatment attenuates amygdala activity in autism: a treatment-mechanism study with long-term follow-up

Intranasal administration of the neuropeptide oxytocin (IN-OT) is increasingly considered as a potential treatment for targeting the core symptoms of autism spectrum disorder (ASD), but the effects of continual use on neural substrates are fairly unexplored and long-term effects are unknown. In this double-blind, randomized, placebo-controlled study, we investigated the effects of single-dose and multiple-dose IN-OT treatment (4 weeks of daily (24 IU) administrations) on brain activity related to processing emotional states. Thirty-eight adult men with ASD (aged between 18 and 35 years) underwent functional magnetic resonance imaging of the posterior superior temporal gyrus (pSTS) and amygdala regions while processing emotional states from point-light biological motion. In line with prior research, a single dose of IN-OT induced a reliable increase in pSTS brain activity during the processing of point-light biological motion, but no consistent long-term changes in pSTS activity were induced after the multiple-dose treatment. In terms of bilateral amygdala, the multiple-dose treatment induced a consistent attenuation in brain activity, which outlasted the period of actual administrations until four weeks and one year post-treatment. Critically, participants with stronger attenuations in amygdala-activity showed greater behavioral improvements, particularly in terms of self-reported feelings of avoidant attachment and social functioning. Together, these observations provide initial insights into the long-lasting neural consequences of chronic IN-OT use on amygdala functioning and provide first indications that the acute versus chronic effects of IN-OT administration may be qualitatively different. Larger studies are however warranted to further elucidate the long-term impact of IN-OT treatment on human neural substrates and its behavioral consequences.

Neural effects of oxytocin and mimicry in frontotemporal dementia: A randomized crossover study

OBJECTIVE

To determine whether intranasal oxytocin, alone or in combination with instructed mimicry of facial expressions, would augment neural activity in patients with frontotemporal dementia (FTD) in brain regions associated with empathy, emotion processing, and the simulation network, as indexed by blood oxygen-level dependent (BOLD) signal during fMRI.

METHODS

In a placebo-controlled, randomized crossover design, 28 patients with FTD received 72 IU intranasal oxytocin or placebo and then completed an fMRI facial expression mimicry task.

RESULTS

Oxytocin alone and in combination with instructed mimicry increased activity in regions of the simulation network and in limbic regions associated with emotional expression processing.

CONCLUSIONS

The findings demonstrate latent capacity to augment neural activity in affected limbic and other frontal and temporal regions during social cognition in patients with FTD, and support the promise and need for further investigation of these interventions as therapeutics in FTD.

CLINICALTRIALSGOV IDENTIFIER

NCT01937013.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that a single dose of 72 IU intranasal oxytocin augments BOLD signal in patients with FTD during viewing of emotional facial expressions.

Oxytocin modulates the effective connectivity between the precuneus and the dorsolateral prefrontal cortex

Our social activity is heavily influenced by the process of introspection, with emerging research suggesting a role for the Default Mode Network (DMN) in social cognition. We hypothesize that oxytocin, a neuropeptide with an important role in social behaviour, can effectively alter the connectivity of the DMN. We test this hypothesis using a randomized, double-blind, crossover, placebo-controlled trial where 15 healthy male participants received 24 IU oxytocin or placebo prior to a resting-state functional MRI scan. We used Granger Causality Analysis for the first time to probe the role of oxytocin on brain networks and found that oxytocin reverses the pattern of effective connectivity between the bilateral precuneus and the left dorsolateral prefrontal cortex (dlPFC), a key central executive network (CEN) region. Under placebo, the bilateral precuneus exerted a significant negative causal influence on the left dlPFC and the left dlPFC exerted a significant positive causal influence on the bilateral precuneus. However, under oxytocin, these patterns were reversed, i.e. positive causal influence from the bilateral precuneus to the left dlPFC and negative causal influence from the left dlPFC to the bilateral precuneus (with statistically significant effects for the right precuneus). We propose that these oxytocin-induced effects could be a mechanistic process by which it modulates social cognition. These results provide a measurable target for the physiological effects of oxytocin in the brain and offer oxytocin as a potential agent to enhance the cooperative role of the predominantly 'task-inactive' 'default mode' brain regions in both healthy and patient populations.

Neuroimaging Markers of Risk and Pathways to Resilience in Autism Spectrum Disorder

Autism spectrum disorder is a complex, heterogeneous neurodevelopmental condition of largely unknown etiology. This heterogeneity of symptom presentation, combined with high rates of comorbidity with other developmental disorders and a lack of reliable biomarkers, makes diagnosing and evaluating life outcomes for individuals with autism spectrum disorder a challenge. We review the growing literature on neuroimaging-based biomarkers of risk for the development of autism and explore evidence for resilience in some autistic individuals. The current literature suggests that neuroimaging during early infancy, in combination with prebirth and early genetic studies, is a promising tool for identifying biomarkers of risk, while studies of gene expression and DNA methylation have provided some key insights into mechanisms of resilience. With genetics and the environment contributing to both risk for the development of autism spectrum disorder and conditions for resilience, additional studies are needed to understand how risk and resilience interact mechanistically, whereby factors of risk may engender conditions for adaptation. Future studies should prioritize longitudinal designs in global cohorts, with the involvement of the autism community as partners in research to help identify domains of functioning that hold value and importance to the community.

Guidelines for wrist-worn consumer wearable assessment of heart rate in biobehavioral research

Researchers have increasingly begun to use consumer wearables or wrist-worn smartwatches and fitness monitors for measurement of cardiovascular psychophysiological processes related to mental and physical health outcomes. These devices have strong appeal because they allow for continuous, scalable, unobtrusive, and ecologically valid data collection of cardiac activity in "big data" studies. However, replicability and reproducibility may be hampered moving forward due to the lack of standardization of data collection and processing procedures, and inconsistent reporting of technological factors (e.g., device type, firmware versions, and sampling rate), biobehavioral variables (e.g., body mass index, wrist dominance and circumference), and participant demographic characteristics, such as skin tone, that may influence heart rate measurement. These limitations introduce unnecessary noise into measurement, which can cloud interpretation and generalizability of findings. This paper provides a brief overview of research using commercial wearable devices to measure heart rate, reviews literature on device accuracy, and outlines the challenges that non-standardized reporting pose for the field. We also discuss study design, technological, biobehavioral, and demographic factors that can impact the accuracy of the passive sensing of heart rate measurements, and provide guidelines and corresponding checklist handouts for future study data collection and design, data cleaning and processing, analysis, and reporting that may help ameliorate some of these barriers and inconsistencies in the literature.

Acute oxytocin effects in inferring others' beliefs and social emotions in people at clinical high risk for psychosis

Social deficits are key hallmarks of the Clinical High Risk for Psychosis (CHR-P) state and of established psychotic disorders, and contribute to impaired social functioning, indicating a potential target for interventions. However, current treatments do not significantly ameliorate social impairments in CHR-P individuals. Given its critical role in social behaviour and cognition, the oxytocinergic (OT) system is a promising target for novel interventions in CHR-P subjects. In a double-blind, placebo-controlled, crossover design, 30 CHR-P males were studied using functional magnetic resonance imaging (fMRI) on two occasions, once after 40IU self-administered intranasal OT and once after placebo. A modified version of the Sally-Anne task was used to assess brain activation during inferring others' beliefs and social emotions. The Reading the Mind in the Eyes Test was acquired prior to the first scan to test whether OT effects were moderated by baseline social-emotional abilities. OT did not modulate behavioural performances but reduced activation in the bilateral inferior frontal gyrus compared with placebo while inferring others' social emotions. Furthermore, the relationship between brain activation and task performance after OT administration was moderated by baseline social-emotional abilities. While task accuracy during inferring others' social emotion increased with decreasing activation in the left inferior frontal gyrus in CHR-P individuals with low social-emotional abilities, there was no such relationship in CHR-P individuals with high social-emotional abilities. Our findings may suggest that acute OT administration enhances neural efficiency in the inferior frontal gyrus during inferring others' social emotions in those CHR-P subjects with low baseline social-emotional abilities.

Oxytocin induces long-lasting adaptations within amygdala circuitry in autism: a treatment-mechanism study with randomized placebo-controlled design

Intranasal administration of the neuropeptide oxytocin (IN-OT) is increasingly explored as a potential treatment for targeting the core symptoms of autism spectrum disorder (ASD). To date, however, the impact of multiple-dose IN-OT treatment on human neural circuitry is largely unknown, and also the possibility that long-term IN-OT use may induce long-lasting neural adaptations remains unexplored. Using a double-blind, randomized, placebo-controlled, between-subject design (including 38 adult men with ASD), this treatment-mechanism study showed that 4 weeks of daily oxytocin administration (24 IU/day) significantly altered intrinsic (resting-state fMRI) functional connectivity of the amygdala to core regions of the "social brain" (particularly orbitofrontal cortex and superior temporal sulcus) up to 4 weeks and 1 year post treatment. The neural adaptations in functional coupling of the amygdala to the orbitofrontal cortex were associated with reduced feelings of avoidance toward others and-at the trend level-reduced repetitive behaviors. These observations contribute to a deeper mechanistic understanding of the neural substrates that underlie behavioral effects of multiple-dose IN-OT treatment, and provide initial insights into the long-lasting neural consequences of chronic IN-OT use on amygdala circuitry. Future studies are however warranted to further elucidate the long-term impact of IN-OT treatment on human neural circuitry and its behavioral consequences.

Epigenetic modification of the oxytocin receptor gene: implications for autism symptom severity and brain functional connectivity

The role of oxytocin in social cognition has attracted tremendous interest in social neuroscience and psychiatry. Some studies have reported improvement in social symptoms following oxytocin treatment in autism spectrum disorders (ASD), while others point to endogenous factors influencing its efficiency and to mixed results in terms of long-term clinical benefits. Epigenetic modification to the oxytocin receptor gene (OXTR) in ASD could be an informative biomarker of treatment efficacy. Yet, little is known about the relationship between OXTR methylation, clinical severity, and brain function in ASD. Here, we investigated the relationship between OXTR methylation, ASD diagnosis (in N = 35 ASD and N = 64 neurotypical group), measures of social responsiveness, and resting-state functional connectivity (rsFC) between areas involved in social cognition and reward processing (in a subset of ASD, N = 30). Adults with ASD showed higher OXTR methylation levels in the intron 1 area compared with neurotypical subjects. This hypermethylation was related to clinical symptoms and to a hypoconnectivity between cortico-cortical areas involved in theory of mind. Methylation at a CpG site in the exon 1 area was positively related to social responsiveness deficits in ASD and to a hyperconnectivity between striatal and cortical brain areas. Taken together, these findings provide initial evidence for OXTR hypermethylation in the intron area as a potential biomarker for adults with ASD with less severe developmental communication deficits, but with impairments in theory of mind and self-awareness. Also, OXTR methylation in the exon 1 area could be a potential biomarker of sociability sensitive to life experiences.

Oxytocin Enhances an Amygdala Circuit Associated With Negative Symptoms in Schizophrenia: A Single-Dose, Placebo-Controlled, Crossover, Randomized Control Trial

Negative symptoms are core contributors to vocational and social deficits in schizophrenia (SZ). Available antipsychotic medications typically fail to reduce these symptoms. The neurohormone oxytocin (OT) is a promising treatment for negative symptoms, given its role in complex social behaviors mediated by the amygdala. In sample 1, we used a double-blind, placebo-controlled, crossover design to test the effects of a single dose of intranasal OT on amygdala resting-state functional connectivity (rsFC) in SZ (n = 22) and healthy controls (HC, n = 24) using a whole-brain corrected approach: we identified regions for which OT modulated SZ amygdala rsFC, assessed whether OT-modulated circuits were abnormal in SZ relative to HC on placebo, and evaluated whether connectivity on placebo and OT-induced connectivity changes correlated with baseline negative symptoms in SZ. Given our modest sample size, we used a second SZ (n = 183) and HC (n = 178) sample to replicate any symptom correlations. In sample 1, OT increased rsFC between the amygdala and left middle temporal gyrus, superior temporal sulcus, and angular gyrus (MTG/STS/AngG) in SZ compared to HC. Further, SZ had hypo-connectivity in this circuit compared to HC on placebo. More severe negative symptoms correlated with less amygdala-to-left-MTG/STS/AngG connectivity on placebo and with greater OT-induced connectivity increases. In sample 2, we replicated the correlation between amygdala-left-MTG/STS/AngG hypo-connectivity and negative symptoms, finding a specific association with expressive negative symptoms. These data suggest intranasal OT can normalize functional connectivity in an amygdala-to-left-MTG/STS/AngG circuit that contributes to negative symptoms in SZ.

Heart and brain: Cortical representation of cardiac signals is disturbed in borderline personality disorder, but unaffected by oxytocin administration

BACKGROUND

Emotional dysregulation, a core feature of borderline personality disorder (BPD) has recently been linked to deficits in the cortical representation of bodily signals. Oxytocin modulates the salience of external social cues. However, its role in interoception is still not fully understood. The aim of the current study was to replicate reduced heartbeat-evoked potentials (HEPs) as a marker for the cortical representation of cardiac signals in BPD and to explore potential effects of oxytocin on HEP amplitude.

METHODS

Fifty-three medication-free women with a DSM-IV diagnosis of BPD and sixty healthy female controls (HCs) participated in the study. In a randomized, double-blind placebo-controlled trial, participants self-administered either 24 I.U. of oxytocin or placebo and took part in a 5-minute resting-state electrocardiogram (ECG) with parallel electroencephalogram (EEG) measurement. In addition, emotional dysregulation and BPD symptomatology were assessed with self-report questionnaires.

RESULTS

Patients with BPD had significantly lower mean HEP amplitudes than HCs. Furthermore, HEP amplitudes were negatively correlated with emotional dysregulation in the whole sample. However, oxytocin had no significant effect on HEP amplitude.

LIMITATIONS

Only female participants were investigated and no clinicial controls were included.

CONCLUSIONS

This is the first replication from an independent sample showing a reduced cortical representation of cardiac signals in BPD patients. This, together with other body-related symptoms, suggests deficits in the processing of bodily signals, which seem to be associated with emotional dysregulation. Whether oxytocin influences HEP during emotion regulation tasks needs to be investigated in future studies.

On the Nature of the Mother-Infant Tie and Its Interaction With Freudian Drives

The affective bond between an infant and its caregiver, the so-called mother-infant tie, was analyzed by various reputable psychologists (e.g., Ainsworth, Clark, Erikson, Anna Freud, Harlow, Klein, Spitz, and Winnicott) but both the basic tenets of the bond and the importance of the trauma of maternal deprivation for personality disorders in adults were introduced by Bowlby. Although Bowlby was a trained psychoanalyst, he rejected central cornerstones of Freudian theory (esp. drive theory) and used concepts promulgated by renowned ethologists (Tinbergen and Lorenz) to establish his framework of "instinctive behavior" that has been developed further into the concept of "attachment theory" under the influence of Mary Ainsworth. However, since any precise experimental facts were lacking when Bowlby formulated his ideas on the concept of instinctive behavior, the whole framework is a descriptive, category-driven approach (like the ones of Freudian drives). In order to connect the mother-infant tie - as propounded by Bowlby - with experimental data, this manuscript undertakes a biochemical analysis of it because this strategy proved somewhat successful in relation to Freudian drives. The analysis unfolded that the neurochemical oxytocin, released by the action of sensory nerves, is of utmost importance for the operation of the mother-infant tie. Furthermore, multiple evidences have been presented to the fact that there is strong interaction between unconsciously operating Freudian drives and the consciously acting mother-infant tie (that is now classified as a drive). The outlined interaction in conjunction with the classification of attachment urges as drives gave a very detailed insight into how a SEEKING-derived reward can be evoked during operation of the mother-infant tie. In summary, there is no need to marginalize either the mother-infant tie or Freudian drives but rather there is need to respect both (principally different) impulses in moving toward a more extensive description.

In the eye of the beholder? Oxytocin effects on eye movements in schizophrenia

BACKGROUND

Individuals with schizophrenia have difficulty in extracting salient information from faces. Eye-tracking studies have reported that these individuals demonstrate reduced exploratory viewing behaviour (i.e. reduced number of fixations and shorter scan paths) compared to healthy controls. Oxytocin has previously been demonstrated to exert pro-social effects and modulate eye gaze during face exploration. In this study, we tested whether oxytocin has an effect on visual attention in patients with schizophrenia.

METHODS

Nineteen male participants with schizophrenia received intranasal oxytocin 40UI or placebo in a double-blind, placebo-controlled, crossover fashion during two visits separated by seven days. They engaged in a free-viewing eye-tracking task, exploring images of Caucasian men displaying angry, happy, and neutral emotional expressions; and control images of animate and inanimate stimuli. Eye-tracking parameters included: total number of fixations, mean duration of fixations, dispersion, and saccade amplitudes.

RESULTS

We found a main effect of treatment, whereby oxytocin increased the total number of fixations, dispersion, and saccade amplitudes, while decreasing the duration of fixations compared to placebo. This effect, however, was non-specific to facial stimuli. When restricting the analysis to facial images only, we found the same effect. In addition, oxytocin modulated fixation rates in the eye and nasion regions.

DISCUSSION

This is the first study to explore the effects of oxytocin on eye gaze in schizophrenia. Oxytocin had enhanced exploratory viewing behaviour in response to both facial and inanimate control stimuli. We suggest that the acute administration of intranasal oxytocin may have the potential to enhance visual attention in schizophrenia.

Effects of intranasal oxytocin on distraction as emotion regulation strategy in patients with post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is characterized by difficulty down-regulating emotional responses towards trauma-reminders. The neuropeptide oxytocin may enhance treatment response in PTSD, by dampening excessive fear and improving fear regulation. However, oxytocin effects on (neural correlates of) cognitive emotion regulation abilities have never been investigated in PTSD patients. Therefore, we investigated behavioral and neural effects of intranasal oxytocin administration (40IU) on distraction as emotion regulation strategy in male and female police officers with and without PTSD (n = 76), using a randomized placebo-controlled cross-over fMRI study. The distraction condition consisted of a working memory task while negative affective pictures were presented. Under placebo, male PTSD patients showed decreased right striatal activity during distraction compared to male trauma-exposed controls, which was unaffected by oxytocin. After oxytocin administration, left thalamus activity during distraction was enhanced in all participants, independent of PTSD status or sex. Although left thalamus activity during distraction did not differ between PTSD patients and controls under placebo, it was negatively correlated with error rates within PTSD patients. Furthermore, oxytocin administration increased functional connectivity between the left thalamus and amygdala in PTSD patients and male trauma-exposed controls. Upregulation of thalamus activity during distraction by oxytocin may enhance cognitive emotion regulation abilities during psychotherapy in PTSD, although this should still be investigated in a clinical setting. Our findings open an important research avenue into oxytocin effects on cognitive emotion regulation in PTSD and other psychiatric disorders characterized by deficient emotion regulation abilities. Registered in the Netherlands Trial Registry, registration number: NTR3516.

The effects of age on cerebral responses to self-initiated actions during social interactions: An exploratory study

Self-initiated action is critical to social interaction and individuals with social anxiety find it particularly difficult to initiate social interactions. We showed earlier that social exclusion encumbered self-initiated actions in the Cyberball task in young adults. Here, we examined whether the behavioral performance and regional responses during self-initiated actions vary with age in 53 participants (21-74 years; 27 men). Behaviorally, participants were slower in tossing the ball during exclusion (EX) than during fair game (FG) sessions in both men and women. In women but not in men the reaction time (RT) burden (RT_EX - RT_FG; RT prolonged during social exclusion) of ball toss was positively correlated with age despite no observed sex difference in Social Interaction Anxiety Scale scores. The pregenual anterior cingulate cortex, thalamus, left occipital cortex (OC) and left insula/orbitofrontal cortex responded to ball toss in EX vs. FG in negative correlation with age in women but not in men. Further, the activation of left OC fully mediated the relationship between age and RT burden in women. Thus, older women are more encumbered in self-initiated action during social exclusion, although this behavioral burden is not reflected in subjective reports of social anxiety. Age-related diminution in OC activities may reflect the neural processes underlying the difficulty in initiating social interactions in women. Together, the findings identified age-sensitive behavioral and neural processes of self-initiated action in the Cyberball task and suggest the importance of considering age and sex differences in studies of social interaction.

Oxytocin reduces top-down control of attention by increasing bottom-up attention allocation to social but not non-social stimuli - A randomized controlled trial

The neuropeptide oxytocin (OXT) may facilitate attention to social stimuli by influencing early stage bottom-up processing although findings in relation to different emotional expressions are inconsistent and its influence on top-down cognitive processing mechanisms unclear. In the current double-blind placebo (PLC) controlled between-subject design study we therefore recruited 71 male subjects (OXT = 34, PLC = 37) to investigate the effects of intranasal OXT (24IU) on both bottom-up attention allocation and top-down attention inhibition using a prosaccade and antisaccade paradigm incorporating social (neutral, happy, fearful, sad, angry faces) and non-social (oval shape) visual stimuli with concurrent eye movement acquisition. Results revealed a marginal significant interaction effect between treatment, condition and task (p = 0.054), with Bonferroni-corrected post-hoc tests indicating that OXT specifically increased antisaccade errors for social stimuli (ps < 0.04, effect sizes 0.46-0.88), but not non-social stimuli. Antisaccades are under volitional control and therefore this may indicate that OXT treatment reduced top-down inhibition. However, the overall findings are consistent with OXT acting to reduce top-down control of attention as a result of increasing bottom-up early attentional processing of social, but not non-social, stimuli in situations where the two systems are in potential conflict. Marked deficits in bottom-up attention allocation to social stimuli have been reported in autism spectrum disorder, within this context OXT may have the potential to increase early attention allocation towards social cues.

Differences in oxytocin and vasopressin levels in individuals suffering from the autism spectrum disorders vs general population - a systematic review

INTRODUCTION

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interactions, communication, and the presence of stereotyped, repetitive behaviors. Oxytocin (OXT) and arginine-vasopressin are neuropeptides produced in hypothalamus and they are related to processing emotions and social behavior. In the light of a growing number of scientific reports related to this issue, the two neurohormones started to be linked with the basis of neurodevelopmental disorders, including the ASD. The aim of this study was a systematic review of previous studies regarding the differences in OXT and vasopressin levels in ASD and neurotypical persons.

MATERIALS AND METHODS

Literature review focused on publications in the last 10 years located via the MEDLINE/PubMed database as well as the Google Scholar browser. Selection was made by assumptive criteria of inclusion and exclusion.

RESULTS

From the 487 studies qualified to the initial abstract analysis, 12 met the six inclusion criteria and were included in the full-text review.

CONCLUSION

Currently, available study reports still do not provide unequivocal answers as to the differences in concentrations of those neuropeptides between children with ASD and neurotypical control. Therefore, it is necessary to continue the research taking into account necessity of proper homogenization of study groups, utilization of objective and quantifiable tools for ASD diagnosis and broadening the range of biochemical and molecular factors analyzed.

Oxytocin Facilitates Self-Serving Rather Than Altruistic Tendencies in Competitive Social Interactions Via Orbitofrontal Cortex

BACKGROUND

While the neuropeptide oxytocin can facilitate empathy and altruistic behavior, it may also promote self-serving tendencies in some contexts, and it remains unclear if it would increase altruistic or self-interest behaviors when they compete within a social situation.

METHODS

The current between-subject, double-blind, placebo-controlled fMRI study investigated the effect of intranasal oxytocin on empathy for social exclusion using a modified online ball-tossing game that incorporated monetary rewards and the potential to display both altruistic and self-interest behaviors.

RESULTS

Results showed that when subjects in both oxytocin and placebo groups were observing a player being excluded (victim) by other players in the game, there was activation in the mentalizing network. When subjects then played both with the victim and the players who had excluded them, they threw more balls to the victim player, indicative of an altruistic response. However, subjects in the oxytocin group threw more balls to the excluder players indicative of greater self-interest, since the latter would be perceived as more likely to reciprocate to maximize financial gain. This behavioral effect of oxytocin was associated with greater medial orbitofrontal cortex activation when playing with the excluders and negatively correlated with trait-altruism scores.

CONCLUSIONS

Overall, our findings suggest that in the context of competing motivations for exhibiting altruistic or self-interest behavior, oxytocin enhanced self-interest and this was associated with greater activation in frontal reward areas.

The influence of oxytocin and vasopressin on men's judgments of social dominance and trustworthiness: An fMRI study of neutral faces

Cues signaling trust and dominance are crucial for social life. Previous studies on the effects of oxytocin (OT) nasal sprays on trustworthiness evaluations have been inconsistent and its influence on dominance is unknown. Vasopressin (AVP) may also influence social cue perception, but even fewer investigations have evaluated this possibility. We evaluated the effects of intranasal OT and AVP compared to placebo control during three double-blinded functional magnetic resonance imaging sessions. Twenty males received a pseudo-randomized order of nasal spray conditions and rated the trustworthiness and dominance of neutral faces. OT increased facial dominance ratings compared to placebo. Neuroimaging results revealed an inverse relationship between brain activation and face ratings for OT compared to placebo in regions involved in processing emotional expressions. Specifically, the right superior temporal gyrus was attenuated as ratings increased and the left precuneus selectively diminished with increasing dominance ratings. Additionally, OT increased functional connectivity between frontoparietal regions and the right amygdala for faces rated as highly dominant, but OT increased connectivity between the fusiform gyrus, hippocampus, and bilateral ventral tegmental area (VTA) for faces perceived as highly trustworthy. Overall, OT increased the perception of dominance but did not influence trustworthiness judgments. However, we observed regional neural effects for OT that differed between judgments of trustworthiness and dominance. AVP attenuated left temporoparietal junction activity as face ratings increased, a result consistent with AVP influencing mentalization. AVP also led to increased left amygdala and right VTA connectivity with the putamen, which is consistent with cue-driven, habitual responses.