Effects of Oxytocin and Vasopressin on Preferential Brain Responses to Negative Social Feedback

Effects of systemic oxytocin receptor activation and blockade on risky decision making in female and male rats

The neuropeptide oxytocin is traditionally known for its roles in parturition, lactation, and social behavior. Other data, however, show that oxytocin can modulate behaviors outside of these contexts, including drug self-administration and some aspects of cost-benefit decision making. Here we used a pharmacological approach to investigate the contributions of oxytocin signaling to decision making under risk of explicit punishment. Female and male Long-Evans rats were trained on a risky decision-making task in which they chose between a small, "safe" food reward and a large, "risky" food reward that was accompanied by varying probabilities of mild footshock. Once stable choice behavior emerged, rats were tested in the task following acute intraperitoneal injections of oxytocin or the oxytocin receptor antagonist L-368,899. Oxytocin dose-dependently reduced preference for the large, risky reward only in females, whereas L-368,899 dose-dependently reduced preference for the large, risky reward in both sexes. Control experiments showed that these effects could not be accounted for by drug-induced alterations in preference for the large reward or shock sensitivity. Together, these results reveal partially sex-dependent effects of oxytocin signaling on risky decision making in rats. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Oxytocin moderates fMRI connectivity and response to implicit threat processing in cocaine use disorder

Stressful social experiences play an important role in increasing vulnerability to substance use, including cocaine. Oxytocin (OXT), known for its anxiolytic properties and involvement in social functioning, has been suggested as a potential therapeutic for cocaine use disorder (CUD). However, limited research has explored OXT's influence on social stress in CUD, and no study has examined its effects on neural response to subconscious (implicit) social threat cues in this population. To address this gap, the present study administered intranasal OXT (24 IU) or placebo (PBO) to participants with CUD (CUD+, N = 76) or without CUD (CUD-, N = 61) in a randomized parallel design. Participants then completed a functional magnetic resonance imaging (fMRI) task involving briefly presented facial fear and anger (i.e., threat) cues, followed by neutral face stimuli. Whole-brain activation and amygdala functional connectivity (using psychophysiological interaction modeling) were examined in response to the facial threat cues. OXT reduced activation in the thalamus and pontine reticular formation in response to fear cues, and in the supplementary motor area for both fear and anger cues, regardless of CUD status. Additionally, under PBO, amygdala-medial prefrontal cortex connectivity to fear stimuli was negative for the CUD+ group, but under OXT, this coupling was positive, similar to the positive coupling observed for the CUD- group under both PBO and OXT administration. The finding of OXT-mediated reversal of amygdala-prefrontal coupling was specific to CUD+ and suggests that OXT alters circuitry related to threat surveillance and implicit emotion regulation in CUD. However, additional research is needed to determine whether these alterations due to OXT have clinical significance in CUD.

Oxytocin, but not vasopressin, decreases willingness to harm others by promoting moral emotions of guilt and shame

Prosocial and moral behaviors have overlapping neural systems and can both be affected in a number of psychiatric disorders, although whether they involve similar neurochemical systems is unclear. In the current registered randomized placebo-controlled trial on 180 adult male and female subjects, we investigated the effects of intranasal administration of oxytocin and vasopressin, which play key roles in influencing social behavior, on moral emotion ratings for situations involving harming others and on judgments of moral dilemmas where others are harmed for a greater good. Oxytocin, but not vasopressin, enhanced feelings of guilt and shame for intentional but not accidental harm and reduced endorsement of intentionally harming others to achieve a greater good. Neither peptide influenced arousal ratings for the scenarios. Effects of oxytocin on guilt and shame were strongest in individuals scoring lower on the personal distress subscale of trait empathy. Overall, findings demonstrate for the first time that oxytocin, but not vasopressin, promotes enhanced feelings of guilt and shame and unwillingness to harm others irrespective of the consequences. This may reflect associations between oxytocin and empathy and vasopressin with aggression and suggests that oxytocin may have greater therapeutic potential for disorders with atypical social and moral behavior.

Neurophysiological response to social feedback in stressful situations

The relationship between external feedback and cognitive and neurophysiological performance has been extensively investigated in social neuroscience. However, few studies have considered the role of positive and negative external social feedback on electroencephalographic (EEG) and moderate stress response. Twenty-six healthy adults underwent a moderately stressful job interview consisting of a modified version of the Trier Social Stress Test. After each preparation, feedback was provided by an external committee, ranging from positive to negative with increasing impact on subjects. Stress response was measured by analysing response times (RTs) during the speech phase, while cognitive performance was assessed using a Stroop-like task before and after the test. Results indicate that RTs used to deliver the final speeches with negative feedback were significantly lower compared with those used for the initial speech with positive feedback. Moreover, a generalized improvement in Stroop-like task performance was observed in the post-SST compared with the pre-SST. Consistent with behavioural results, EEG data indicated greater delta, theta, and alpha band responses in right prefrontal and left central areas, and for delta and theta bands, also in parietal areas in response to positive feedback compared with aversive-neutral feedback, highlighting greater cognitive effort required by the former. Conversely, an increase in these bands in right and left temporal and left occipital areas was observed following negative and aversive feedback, indicative of an adaptive response to stress and emotion-regulatory processes. These findings suggest that negative social feedback in moderately stressful and noncritical conditions could contribute to improving individual cognitive performance.

Effects of arginine vasopressin on human anxiety and associations with sex, dose, and V1a-receptor genotype

RATIONALE

Arginine vasopressin (AVP) has dose- and sex-specific effects on social behavior, and variation in social responses is related to variation in the V1a receptor gene in animals. Whether such complexity also characterizes AVP effects on anxiety in humans, or whether V1a genotype is related to anxiety and/or AVP's ability to affect it, remains to be determined.

OBJECTIVE

To test if AVP has dose-dependent effects on anxiety in men and/or women and if a particular allele within the RS3 promoter region of the V1a receptor gene is associated with anxiety and/or AVP effects on anxiety.

METHOD

Men and women self-administered 20 IU or 40 IU intranasal arginine vasopressin (AVP) and placebo in a double-blind, within-subjects design, and State (SA) and Trait (TA) anxiety were measured 60 min later. PCR was used to identify allelic variation within the RS3 region of the V1a receptor gene.

RESULTS

AVP decreased SA in men across both doses, whereas only the lower dose had the same effect, across sexes, in individuals who carry at least one copy of a previously identified "risk" allele in the RS3 promoter of the V1a receptor gene. Additionally, after placebo, women who carried a copy of the allele displayed lower TA than women who did not, and AVP acutely increased TA scores in those women.

CONCLUSIONS

Exogenous AVP has modest sex- and dose-dependent effects on anxiety/affect in humans. Further, allelic variation in the V1a promoter appears associated with responsiveness to AVP's effects and, at least in women, to stable levels of anxiety/affect.

Effects of systemic oxytocin receptor activation and blockade on risky decision making in female and male rats

The neuropeptide oxytocin is traditionally known for its roles in parturition, lactation, and social behavior. Other data, however, show that oxytocin can modulate behaviors outside of these contexts, including drug self-administration and some aspects of cost-benefit decision making. Here we used a pharmacological approach to investigate the contributions of oxytocin signaling to decision making under risk of explicit punishment. Female and male Long-Evans rats were trained on a risky decision-making task in which they chose between a small, "safe" food reward and a large, "risky" food reward that was accompanied by varying probabilities of mild footshock. Once stable choice behavior emerged, rats were tested in the task following acute intraperitoneal injections of oxytocin or the oxytocin receptor antagonist L-368,899. Neither drug affected task performance in males. In females, however, both oxytocin and L-368,899 caused a dose-dependent reduction in preference for large risky reward. Control experiments showed that these effects could not be accounted for by alterations in food motivation or shock sensitivity. Together, these results reveal a sex-dependent effect of oxytocin signaling on risky decision making in rats.

The neurocognitive impact of loneliness and social networks on social adaptation

Social adaptation arises from the interaction between the individual and the social environment. However, little empirical evidence exists regarding the relationship between social contact and social adaptation. We propose that loneliness and social networks are key factors explaining social adaptation. Sixty-four healthy subjects with no history of psychiatric conditions participated in this study. All participants completed self-report questionnaires about loneliness, social network, and social adaptation. On a separate day, subjects underwent a resting state fMRI recording session. A hierarchical regression model on self-report data revealed that loneliness and social network were negatively and positively associated with social adaptation. Functional connectivity (FC) analysis showed that loneliness was associated with decreased FC between the fronto-amygdalar and fronto-parietal regions. In contrast, the social network was positively associated with FC between the fronto-temporo-parietal network. Finally, an integrative path model examined the combined effects of behavioral and brain predictors of social adaptation. The model revealed that social networks mediated the effects of loneliness on social adaptation. Further, loneliness-related abnormal brain FC (previously shown to be associated with difficulties in cognitive control, emotion regulation, and sociocognitive processes) emerged as the strongest predictor of poor social adaptation. Findings offer insights into the brain indicators of social adaptation and highlight the role of social networks as a buffer against the maladaptive effects of loneliness. These findings can inform interventions aimed at minimizing loneliness and promoting social adaptation and are especially relevant due to the high prevalence of loneliness around the globe. These findings also serve the study of social adaptation since they provide potential neurocognitive factors that could influence social adaptation.

Null results of oxytocin and vasopressin administration on mentalizing in a large fMRI sample: evidence from a randomized controlled trial

BACKGROUND

Although potential links between oxytocin (OT), vasopressin (AVP), and social cognition are well-grounded theoretically, most studies have included all male samples, and few have demonstrated consistent effects of either neuropeptide on mentalizing (i.e. understanding the mental states of others). To understand the potential of either neuropeptide as a pharmacological treatment for individuals with impairments in social cognition, it is important to demonstrate the beneficial effects of OT and AVP on mentalizing in healthy individuals.

METHODS

In the present randomized, double-blind, placebo-controlled study (n = 186) of healthy individuals, we examined the effects of OT and AVP administration on behavioral responses and neural activity in response to a mentalizing task.

RESULTS

Relative to placebo, neither drug showed an effect on task reaction time or accuracy, nor on whole-brain neural activation or functional connectivity observed within brain networks associated with mentalizing. Exploratory analyses included several variables previously shown to moderate OT's effects on social processes (e.g., self-reported empathy, alexithymia) but resulted in no significant interaction effects.

CONCLUSIONS

Results add to a growing literature demonstrating that intranasal administration of OT and AVP may have a more limited effect on social cognition, at both the behavioral and neural level, than initially assumed. Randomized controlled trial registrations: ClinicalTrials.gov; NCT02393443; NCT02393456; NCT02394054.

Intranasal oxytocin attenuates the effects of monetary feedback on procedural learning

Procedural learning is a vital brain function that allows us to acquire motor skills during development or re-learn them after lesions affecting the motor system. Procedural learning can be improved by feedback of different valence, e.g., monetary or social, mediated by dopaminergic circuits. While processing motivationally relevant stimuli, dopamine interacts closely with oxytocin, whose effects on procedural learning, particularly feedback-based approaches, remain poorly understood. In a randomized, double-blind, placebo-controlled trial, we investigated whether oxytocin modulates the differential effects of monetary and social feedback on procedural learning. Sixty-one healthy male participants were randomized to receive a placebo or oxytocin intranasally. The participants then performed a modified serial reaction time task. Oxytocin plasma concentrations were measured before and after applying the placebo or verum. Groups did not differ regarding general reaction times or measures of procedural learning. For the placebo group, monetary feedback improved procedural learning compared to a neutral control condition. In contrast, the oxytocin group did not show a differential effect of monetary or social feedback despite a significant increase in oxytocin plasma levels after intranasal application. The data suggest that oxytocin does not influence procedural learning per se. Instead, oxytocin seems to attenuate the effects of monetary feedback on procedural learning specifically.

Intranasal vasopressin like oxytocin increases social attention by influencing top-down control, but additionally enhances bottom-up control

The respective roles of the neuropeptides arginine vasopressin (AVP) and oxytocin (OXT) in modulating social cognition and for therapeutic intervention in autism spectrum disorder have not been fully established. In particular, while numerous studies have demonstrated effects of oxytocin in promoting social attention the role of AVP has not been examined. The present study employed a randomized, double-blind, placebo (PLC)-controlled between-subject design to explore the social- and emotion-specific effects of AVP on both bottom-up and top-down attention processing with a validated emotional anti-saccade eye-tracking paradigm in 80 healthy male subjects (PLC = 40, AVP = 40). Our findings showed that AVP increased the error rate for social (angry, fearful, happy, neutral and sad faces) but not non-social (oval shapes) stimuli during the anti-saccade condition and reduced error rates in the pro-saccade condition. Comparison of these findings with a previous study (sample size: PLC = 33, OXT = 33) using intranasal oxytocin revealed similar effects of the two peptides on anti-saccade errors, although with some difference in effects of specific face emotions, but a significantly greater effect of AVP on pro-saccades. Both peptides also produced a post-task anxiolytic effect by reducing state anxiety. Together these findings suggested that both AVP and OXT decrease goal-directed top-down attention control to social salient stimuli but that AVP more potently increased bottom-up social attentional processing.

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.

Age and intranasal oxytocin effects on trust-related decisions after breach of trust: Behavioral and brain evidence

Age-related differences in cognition and socioemotional functions, and in associated brain regions, may reduce sensitivity to cues of untrustworthiness, with effects on trust-related decision making and trusting behavior. This study examined age-group differences in brain activity and behavior during a trust game. In this game, participants received "breach-of-trust" feedback after half of the trials. The feedback indicated that only 50% of the monetary investment into their fellow players had resulted in returns. The study also explored the effects of intranasal oxytocin on trust-related decisions in aging, based on suggestions of a modulatory role of oxytocin in response to negative social stimuli and perceptions of trust. Forty-seven younger and 46 older participants self-administered intranasal oxytocin or placebo, in a randomized, double-blind, between-subjects procedure, before they engaged in the trust game while undergoing functional magnetic resonance imaging (fMRI). Younger participants invested less into their game partners after breach-of-trust feedback, while older participants showed no significant difference in their investment after breach-of-trust feedback. Oxytocin did not modulate the behavioral effects. However, after breach-of-trust feedback, older participants in the oxytocin group showed less activity in the left superior temporal gyrus. In contrast, older participants in the placebo group showed more activity in left superior temporal gyrus after breach of trust. The findings may reflect reduced responsiveness to cues of untrustworthiness in older adults. Furthermore, the modulatory effect of oxytocin on left superior temporal gyrus activity among older adults supports the neuropeptide's age-differential role in neural processes in aging, including in the context of trust-related decision making. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Oxytocin-induced facilitation of learning in a probabilistic task is associated with reduced feedback- and error-related negativity potentials

BACKGROUND

Feedback evaluation of actions and error response detection are critical for optimizing behavioral adaptation. Oxytocin can facilitate learning following social feedback but whether its effects vary as a function of feedback valence remains unclear.

AIMS

The present study aimed to investigate whether oxytocin would influence responses to positive and negative feedback differentially or equivalently.

METHODS

The present study employed a randomized, double-blind, placebo controlled within-subject design to investigate whether intranasal oxytocin (24 IU) influenced behavioral and evoked electrophysiological potential responses to positive or negative feedback in a probabilistic learning task.

RESULTS

Results showed that oxytocin facilitated learning and this effect was maintained in the absence of feedback. Using novel stimulus pairings, we found that oxytocin abolished bias towards learning more from negative feedback under placebo by increasing accuracy for positively reinforced stimuli. Oxytocin also decreased the feedback-related negativity difference (negative minus positive feedback) during learning, further suggesting that it rendered the evaluation of positive and negative feedback more equivalent. Additionally, post-learning oxytocin attenuated error-related negativity amplitudes but increased the late error positivity, suggesting that it may lower conflict detection between actual errors and expected correct responses at an early stage of processing but at a later stage increase error awareness and motivation for avoiding them.

CONCLUSIONS

Oxytocin facilitates learning and subsequent performance by rendering the impact of positive relative to negative feedback more equivalent and also by reducing conflict detection and increasing error awareness, which may be beneficial for behavioral adaption.

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.

Effects of oxytocin administration and conditioned oxytocin on brain activity: An fMRI study

It has been demonstrated that secretion of several hormones can be classically conditioned, however, the underlying brain responses of such conditioning have never been investigated before. In this study we aimed to investigate how oxytocin administration and classically conditioned oxytocin influence brain responses. In total, 88 females were allocated to one of three groups: oxytocin administration, conditioned oxytocin, or placebo, and underwent an experiment consisting of three acquisition and three evocation days. Participants in the conditioned group received 24 IU of oxytocin together with a conditioned stimulus (CS) during three acquisition days and placebo with the CS on three evocation days. The oxytocin administration group received 24 IU of oxytocin and the placebo group received placebo during all days. On the last evocation day, fMRI scanning was performed for all participants during three tasks previously shown to be affected by oxytocin: presentation of emotional faces, crying baby sounds and heat pain. Region of interest analysis revealed that there was significantly lower activation in the right amygdala and in two clusters in the left superior temporal gyrus in the oxytocin administration group compared to the placebo group in response to observing fearful faces. The activation in the conditioned oxytocin group was in between the other two groups for these clusters but did not significantly differ from either group. No group differences were found in the other tasks. Preliminary evidence was found for brain activation of a conditioned oxytocin response; however, despite this trend in the expected direction, the conditioned group did not significantly differ from other groups. Future research should, therefore, investigate the optimal timing of conditioned endocrine responses and study whether the findings generalize to other hormones as well.

Vasopressin enhances human preemptive strike in both males and females

The neuropeptide arginine vasopressin (AVP), which is known to modulate a wide range of social behaviors in animals, has been identified as a modulator of various negative responses to social stimuli in humans. However, behavioral evidence directly supporting its involvement in human defensive aggression has been rare. We investigated the effect of intranasal AVP on defensive aggression in a laboratory experiment, using an incentivized economic game called the “preemptive strike game” (PSG). Participants played PSG individually (1 on 1) as well as in pairs (2 on 2) under either AVP or saline. We observed that exogenous but not basal AVP modulated the attack rate in PSG for both male and female participants. A model-based analysis of the aggregation of individual attack preferences into pair decisions revealed that the AVP effect on defensive aggression occurred mainly at the individual level and was not amplified at the pair level. Overall, these results present the first evidence that intranasal AVP promotes human defensive aggression for both males and females in a bilateral situation where each party can potentially damage the resources of the other party. These findings also parallel accumulating evidence from non-human animals concerning AVP’s involvement in territorial defense against potential intruders.

Oxytocin and excitation/inhibition balance in social recognition

Social recognition is the sensitive domains of complex behavior critical for identification, interpretation and storage of socially meaningful information. Social recognition develops throughout childhood and adolescent, and is affected in a wide variety of psychiatric disorders. Recently, new data appeared on the molecular mechanisms of these processes, particularly, the excitatory-inhibitory (E/I) ratio which is modified during development, and then E/I balance is established in the adult brain. While E/I imbalance has been proposed as a mechanism for schizophrenia, it also seems to be the common mechanism in autism spectrum disorder (ASD). In addition, there is a strong suggestion that the oxytocinergic system is related to GABA-mediated E/I control in the context of brain socialization. In this review, we attempt to summarize the underpinning molecular mechanisms of E/I balance and its imbalance, and related biomarkers in the brain in healthiness and pathology. In addition, because there are increasing interest on oxytocin in the social neuroscience field, we will pay intensive attention to the role of oxytocin in maintaining E/I balance from the viewpoint of its effects on improving social impairment in psychiatric diseases, especially in ASD.

Oxytocin and brain activity in humans: A systematic review and coordinate-based meta-analysis of functional MRI studies

Oxytocin (OXT) is a neuropeptide which has a critical role in human social behaviour and cognition. Research investigating the role of OXT on functional brain changes in humans has often used task paradigms that probe socioemotional processes. Preliminary evidence suggests a central role of the amygdala in the social cognitive effects of intranasal OXT (IN-OXT), however, inconsistencies in task-design and analysis methods have led to inconclusive findings regarding a cohesive model of the neural mechanisms underlying OXT's actions. The aim of this meta-analysis was to systematically investigate these findings. A systematic search of PubMed, PsycINFO, and Scopus databases was conducted for fMRI studies which compared IN-OXT to placebo in humans. First, we systematically reviewed functional magnetic resonance imaging (fMRI) studies of IN-OXT, including studies of healthy humans, those with clinical disorders, and studies examining resting-state fMRI (rsfMRI). Second, we employed a coordinate-based meta-analysis for task-based neuroimaging literature using activation likelihood estimation (ALE), whereby, coordinates were extracted from clusters with significant differences in IN-OXT versus placebo in healthy adults. Data were included for 39 fMRI studies that reported a total of 374 distinct foci. The meta-analysis identified task-related IN-OXT increases in activity within a cluster of the left superior temporal gyrus during tasks of emotion processing. These findings are important as they implicate regions beyond the amygdala in the neural effects of IN-OXT. The outcomes from this meta-analysis can guide a priori predictions for future OXT research, and provide an avenue for targeted treatment interventions.

Oxytocin Facilitates Empathic- and Self-embarrassment Ratings by Attenuating Amygdala and Anterior Insula Responses

The hypothalamic neuropeptide oxytocin has been reported to enhance emotional empathy in association with reduced amygdala activation, although to date studies have not investigated empathy for individuals expressing self-conscious, moral emotions which engage mentalizing as well as emotion processing networks. In the current randomized, double-blind placebo controlled functional MRI experiment in 70 male and female subjects we have therefore investigated the effects of intranasal oxytocin (40 IU) on behavioral and neural responses to embarrassment experienced by others or by self. Results showed that oxytocin significantly increased ratings of both empathic and self-embarrassment and concomitantly decreased skin conductance response, activation in the right amygdala and insula but not in the medial prefrontal cortex. The amygdala effects of oxytocin were associated with the magnitude of the skin conductance response and trait anxiety scores. Overall our results demonstrate that oxytocin increases ratings of self- and other embarrassment and that this is associated with reduced physiological arousal and activity in neural circuits involved in emotional arousal. The neural effects of oxytocin were more pronounced stronger in individuals with high trait anxiety suggesting that it may particularly reduce their anxiety in embarrassing situations.

Imaging neuropeptide effects on human brain function

The discovery of prosocial effects of oxytocin (OT) opened new directions for studying neuropeptide effects on the human brain. However, despite obvious effects of OT on neural responses as reported in numerous studies, other peptides have received less attention. Therefore, we will only briefly summarize evidence of OT effects on human functional magnetic resonance imaging (fMRI) and primarily focus on OT's sister neuropeptide arginine-vasopressin by presenting our own coordinated-based activation likelihood estimation meta-analysis. In addition, we will recapitulate rather limited data on few other neuropeptides, including pharmacological and genetic fMRI studies. Finally, we will review experiments with external neuropeptide administration to patients afflicted with mental disorders, such as autism or schizophrenia. In conclusion, despite remaining uncertainty regarding the penetrance of exogenous neuropeptides through the blood-brain barrier, it is evident that neuropeptides simultaneously influence the activity of limbic and cortical areas, indicating that these systems have a good potential for therapeutic drug development. Hence, this calls for further systematic studies of a wide spectrum of known and less known neuropeptides to understand their normal function in the brain and, subsequently, to tackle their potential contribution for pathophysiological mechanisms of mental disorders.

Oxytocin biases men to be more or less tolerant of others' dislike dependent upon their relationship status

The experience of being liked or disliked by others strongly influences our liking for and willingness to socialize with them. The neuropeptide oxytocin is involved in social bonding and can modify social preferences for others dependent upon their characteristics. However, it is unclear whether oxytocin affects individuals' reactions to social evaluations made by others (i.e., being liked or disliked) and if this is influenced by already having a secure partner bond (i.e., being single or in a relationship). We therefore performed a double-blind, between-subject, placebo controlled design study on 86 healthy males to investigate the effects of intranasal oxytocin (40IU) on the respective impact of being liked or disliked by others, and whether this was influenced by current relationship status.

RESULTS

showed while oxytocin decreased negative reactions to being disliked in single men it had the opposite effect on men in a relationship, and this occurred primarily when dislike was expressed by females rather than males. In contrast, for men in a relationship oxytocin enhanced mood and affiliation tendency following being liked independent of the gender of the feedback provider. Thus, oxytocin may make single men looking for a potential partner more positive socially even towards females who dislike them, but has the opposite effect in men in a relationship who are not looking for a partner. These results provide further support for the context-dependency of oxytocin effects' on social preferences, and thereby the social salience hypothesis-based explanation of its actions.

Early Intranasal Vasopressin Administration Impairs Partner Preference in Adult Male Prairie Voles (Microtus ochrogaster)

Research supports a modulatory role for arginine vasopressin (AVP) in the expression of socially motivated behaviors in mammals. The acute effects of AVP administration are demonstrably pro-social across species, providing the justification for an ever-increasing measure of clinical interest over the last decade. Combining these results with non-invasive intranasal delivery results in an attractive system for offering intranasal AVP (IN-AVP) as a therapeutic for the social impairments of children with autism spectrum disorder. But, very little is known about the long-term effects of IN-AVP during early development. In this experiment, we explored whether a single week of early juvenile administration of IN-AVP (low = 0.05 IU/kg, medium = 0.5 IU/kg, high = 5.0 IU/kg) could impact behavior across life in prairie voles. We found increases in fecal boli production during open field and novel object recognition testing for the medium dose in both males and females. Medium-dose females also had significantly more play bouts than control when exposed to novel conspecifics during the juvenile period. Following sexual maturity, the medium and high doses of IN-AVP blocked partner preference formation in males, while no such impairment was found for any of the experimental groups in females. Finally, the high-dose selectively increased adult male aggression with novel conspecifics, but only after extended cohabitation with a mate. Our findings confirm that a single week of early IN-AVP treatment can have organizational effects on behavior across life in prairie voles. Specifically, the impairments in pair-bonding behavior experienced by male prairie voles should raise caution when the prosocial effects of acute IN-AVP demonstrated in other studies are extrapolated to long-term treatment.