Inverse effects of oxytocin on attributing mental activity to others in depressed and healthy subjects: a double-blind placebo controlled FMRI study

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.

Four-week intranasal oxytocin administration reduces attachment avoidance in older women

The neuropeptide oxytocin (OT) serves as a critical modulator of social cognition and social behavior. Adult attachment is an affiliative process crucial for social interaction across adulthood. Insecure adult attachment comprises two broad dimensions, attachment anxiety and attachment avoidance. Both these dimensions of attachment are currently understudied regarding OT modulation, and especially in older adults. The present study determined the effects of chronic intranasal OT administration on adult attachment in generally healthy older women and men (aged 55-95 years). Embedded in a larger project, participants were randomly assigned to self-administer 24 international units of either OT or a placebo (P) intranasally twice daily for four weeks. The Experiences in Close Relationships Scale assessed adult attachment (anxiety and avoidance) pre- and post-treatment. There was no significant pre- to post-treatment change in attachment avoidance overall, but the treatment x timepoint x sex interaction was significant, in that women (but not men) in the OT (vs. P) group reported decreased attachment avoidance. No comparable effects were observed for attachment anxiety. Results suggest that older women may benefit from chronic intranasal OT treatment by experiencing less attachment avoidance in their adult relationships.

Mentalization, Oxytocin, and Cortisol in the General Population

Although evidence suggests the role of oxytocin and cortisol in social cognition and emotion regulation, it is less known how their peripheral levels are related to social perception (biological motion detection) and mentalization (self-reflection, emotional awareness, and affect regulation) in the general population. We assessed 150 healthy individuals from the general community on a mentalization questionnaire, a scale measuring the intensity of positive and negative emotions, and measured oxytocin and cortisol levels in the saliva. Oxytocin but not cortisol level and biological motion detection predicted mentalization abilities. There was a positive correlation between mentalization and positive emotions and between mentalization and biological motion detection. These results suggest that oxytocin, but not cortisol, plays a role in low-level perceptual and self-reflective aspects of social cognition.

Intertwined associations between oxytocin, immune system and major depressive disorder

Major depressive disorder (MDD) is a prominent psychiatric disorder with a high prevalence rate. The recent COVID-19 pandemic has exacerbated the already high prevalence of MDD. Unfortunately, a significant proportion of patients are unresponsive to conventional treatments, necessitating the exploration of novel therapeutic strategies. Oxytocin, an endogenous neuropeptide, has emerged as a promising candidate with anxiolytic and antidepressant properties. Oxytocin has been shown to alleviate emotional disorders by modulating the hypothalamic-pituitary-adrenal (HPA) axis and the central immune system. The dysfunction of the immune system has been strongly linked to the onset and progression of depression. The central immune system is believed to be a key target of oxytocin in ameliorating emotional disorders. In this review, we examine the evidence regarding the interactions between oxytocin, the immune system, and depressive disorder. Moreover, we summarize and speculate on the potential roles of the intertwined association between oxytocin and the central immune system in treating emotional disorders.

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 alters attention to emotional facial expressions, particularly for males and those with depressive symptoms

Intranasal oxytocin (OT) can enhance emotion recognition, perhaps by promoting increased attention to social cues. Some studies indicate that individuals with difficulties processing social information, including those with psychopathology, show more pronounced effects in response to OT. As such, there is interest in the potential therapeutic use of OT in populations with deficits in social cognition. The present study examined the effects of intranasal OT on the processing of facial features and selective attention to emotional facial expressions, as well as whether individual differences in depressive symptom severity predict sensitivity to intranasal OT. In a double-blind placebo-controlled within-subject design, eye tracking was used to measure attention to facial features in an emotional expression appraisal task, and attention to emotional expressions in a free-viewing task with a quadrant of multiple faces. OT facilitated the processing of positive cues, enhancing the maintenance of attention to the mouth region of happy faces and to happy faces within a quadrant, with similar effect sizes, despite the latter effect not being statistically significant. Further, persons with depressive symptoms, and particularly males, were sensitive to OT's effects. For males only, OT, relative to placebo, increased attentional focus to the mouth region of all faces. Individuals with depressive symptoms showed less attentional focus on angry (males only) and sad facial expressions, and more attention to happy faces (particularly for males). Results indicate increased sensitivity to OT in males and persons at risk for depression, with OT administration promoting a positive bias in selective attention to social stimuli.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

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.

Reading language of the eyes

The need for assessment of social skills in clinical and neurotypical populations has led to the widespread, and still increasing use of the 'Reading the Mind in the Eyes Test' (RMET) developed more than two decades ago by Simon Baron-Cohen and colleagues for evaluation of social cognition in autism. By analyzing most recent clinical and brain imaging data, we illuminate a set of factors decisive for using the RMET. Converging evidence indicates: (i) In neurotypical individuals, RMET scores are tightly correlated with other social skills (empathy, emotional intelligence, and body language reading); (ii) The RMET assesses recognition of facial affect, but also heavily relies on receptive language skills, semantic knowledge, and memory; (iii) RMET performance is underwritten by the large-scale ensembles of neural networks well-outside the social brain; (iv) The RMET is limited in its capacity to differentiate between neuropsychiatric conditions as well as between stages and severity of a single disorder, though it reliably distinguishes individuals with altered social cognition or elevated pathological traits from neurotypical persons; (v) Merely gender (as a social construct) rather than neurobiological sex influences performance on the RMET; (vi) RMET scores do not substantially decline in healthy aging, and they are higher with higher education level, cognitive abilities, literacy, and mental well-being; (vii) Accuracy on the RMET, and engagement of the social brain, are greater when emotions are expressed and recognized by individuals with similar cultural/ethnic background. Further research is required to better inform usage of the RMET as a tool for swift and reliable examination of social cognition. In light of comparable visual input from the RMET images and faces covered by masks due to COVID-19 regulations, the analysis is of value for keeping efficient social interaction during the current pandemic, in particular, in professional settings related to social communication.

Multiple Aspects of Inappropriate Action of Renin-Angiotensin, Vasopressin, and Oxytocin Systems in Neuropsychiatric and Neurodegenerative Diseases

The cardiovascular system and the central nervous system (CNS) closely cooperate in the regulation of primary vital functions. The autonomic nervous system and several compounds known as cardiovascular factors, especially those targeting the renin-angiotensin system (RAS), the vasopressin system (VPS), and the oxytocin system (OTS), are also efficient modulators of several other processes in the CNS. The components of the RAS, VPS, and OTS, regulating pain, emotions, learning, memory, and other cognitive processes, are present in the neurons, glial cells, and blood vessels of the CNS. Increasing evidence shows that the combined function of the RAS, VPS, and OTS is altered in neuropsychiatric/neurodegenerative diseases, and in particular in patients with depression, Alzheimer's disease, Parkinson's disease, autism, and schizophrenia. The altered function of the RAS may also contribute to CNS disorders in COVID-19. In this review, we present evidence that there are multiple causes for altered combined function of the RAS, VPS, and OTS in psychiatric and neurodegenerative disorders, such as genetic predispositions and the engagement of the RAS, VAS, and OTS in the processes underlying emotions, memory, and cognition. The neuroactive pharmaceuticals interfering with the synthesis or the action of angiotensins, vasopressin, and oxytocin can improve or worsen the effectiveness of treatment for neuropsychiatric/neurodegenerative diseases. Better knowledge of the multiple actions of the RAS, VPS, and OTS may facilitate programming the most efficient treatment for patients suffering from the comorbidity of neuropsychiatric/neurodegenerative and cardiovascular diseases.

Role of Oxytocin in Different Neuropsychiatric, Neurodegenerative, and Neurodevelopmental Disorders

Oxytocin has recently gained significant attention because of its role in the pathophysiology and management of dominant neuropsychiatric disorders. Oxytocin, a peptide hormone synthesized in the hypothalamus, is released into different brain regions, acting as a neurotransmitter. Receptors for oxytocin are present in many areas of the brain, including the hypothalamus, amygdala, and nucleus accumbens, which have been involved in the pathophysiology of depression, anxiety, schizophrenia, autism, Alzheimer's disease, Parkinson's disease, and attention deficit hyperactivity disorder. Animal studies have spotlighted the role of oxytocin in social, behavioral, pair bonding, and mother-infant bonding. Furthermore, oxytocin protects fetal neurons against injury during childbirth and affects various behaviors, assuming its possible neuroprotective characteristics. In this review, we discuss some of the concepts and mechanisms related to the role of oxytocin in the pathophysiology and management of some neuropsychiatric, neurodegenerative, and neurodevelopmental disorders.

Depressive symptoms and social context modulate oxytocin's effect on negative memory recall

Oxytocin promotes social affiliation across various species, in part by altering social cognition to facilitate approach behaviour. However, the effects of intranasal oxytocin on human social cognition are mixed, perhaps because its effects are context dependent and subject to inter-individual differences. Few studies have included explicit manipulations of social context to test this supposition. We examined oxytocin's effects on autobiographical memory recall in two contexts, with and without social contact, and evaluated whether these effects were moderated by depressive symptoms. Two non-clinical samples (Study 1, n = 48; Study 2, n = 63) completed randomised, placebo-controlled, within-subject experiments. We assessed autobiographical memory recall across two sessions (intranasal oxytocin or placebo) and two contexts (memories elicited by an experimenter or by computer). Overall, intranasal oxytocin increased ratings of the vividness of recalled memories during the social context only. Individuals with elevated depressive symptoms also recalled memories that were more negative following oxytocin relative to placebo only in the non-social context across the two studies. Findings highlight the negative consequences of increasing oxytocin bioavailability in vulnerable persons in the absence of social contact. Contextual factors such as social isolation among depressed populations may complicate the clinical use of oxytocin.

Induction of Relaxation by Autonomous Sensory Meridian Response

Background: Autonomous sensory meridian response (ASMR) is used by young people to induce relaxation and sleep and to reduce stress and anxiety; it comprises somatosensation caused by audiovisual stimuli (triggers) that lead to positive emotions. Auditory stimuli play the most important role among the triggers involved in ASMR and have been reported to be more triggering than visual stimuli. On the other hand, classical music is also known to have a relaxing effect. This is the first study to clarify the difference in brain activation associated with relaxation effects between ASMR and classical music by limiting ASMR to auditory stimulation alone.

Methods: Thirty healthy subjects, all over 20 years of age, underwent fMRI while listening to ASMR and classical music. We compared the differences in brain activation associated with classical music and ASMR stimulation. After the experiment, the subjects were administered a questionnaire on somatosensation and moods. After the experiment, the participants were asked whether they experienced ASMR somatosensation or frisson. They were also asked to rate the intensity of two moods during stimulation: “comfortable mood,” and “tingling mood”.

Result: The results of the questionnaire showed that none of the participants experienced any ASMR somatosensation or frisson. Further, there was no significant difference in the ratings given to comfort mood, but there was a significant difference in those given to tingling mood. In terms of brain function, classical music and ASMR showed significant activation in common areas, while ASMR showed activation in more areas, with the medial prefrontal cortex being the main area of activation during ASMR.

Conclusion: Both classical music and the ASMR auditory stimulus produced a pleasant and relaxed state, and ASMR involved more complex brain functions than classical music, especially the activation of the medial prefrontal cortex. Although ASMR was limited to auditory stimulation, the effects were similar to those of listening to classical music, suggesting that ASMR stimulation can produce a pleasant state of relaxation even if it is limited to the auditory component, without the somatic sensation of tingling. ASMR stimulation is easy to use, and appropriate for wellness purposes and a wide range of people.

The association of oxytocin with major depressive disorder: role of confounding effects of antidepressants

Major depressive disorder is a genetic susceptible disease, and a psychiatric syndrome with a high rate of incidence and recurrence. Because of its complexity concerning etiology and pathogenesis, the cure rate of first-line antidepressants is low. In recent years, accumulative evidences revealed that oxytocin act as a physiological or pathological participant in a variety of complex neuropsychological activities, including major depressive disorder. Six electronic databases (Web of Science, PubMed, Scopus, Google Scholar, CNKI, and Wanfang) were employed for researching relevant publications. At last, 226 articles were extracted. The current review addresses the correlation of the oxytocin system and major depressive disorder. Besides, we summarize the mechanisms by which the oxytocin system exerts potential antidepressant effects, including regulating neuronal activity, influencing neuroplasticity and regeneration, altering neurotransmitter release, down regulating hypothalamic-pituitary-adrenal axis, anti-inflammatory, antioxidation, and genetic effects. Increasing evidence shows that oxytocin and its receptor gene may play a potential role in major depressive disorder. Future research should focus on the predictive ability of the oxytocin system as a biomarker, as well as its role in targeted prevention and early intervention of major depressive disorder.

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.

What's Love Got to do with it: Role of oxytocin in trauma, attachment and resilience

Oxytocin (OT) is a neurohypophysial hormone and neuropeptide produced by the hypothalamus and released by the pituitary gland. It has multiple physiological roles including stimulation of parturition and lactation, and promotion of pro-adaptive social behaviors necessary for mammalian survival. OT interacts with one receptor subtype: the OT receptor (OTR) which, upon stimulation, triggers different intracellular signal transduction cascades to mediate its physiological actions. Preclinical studies show that OT regulates social behaviors such as pair bonding, recognition and social interaction. It also coordinates the activation of the hypothalamic-pituitary-adrenal (HPA) axis and the release of corticotrophin-releasing hormone. Further evidence suggests that OT plays an important role in regulating caloric intake and metabolism, and in maintaining electrolyte and cardiovascular homeostasis. OT is also involved in attenuating the neurophysiological and neurochemical effects of trauma on the brain and body by facilitating both physical attachment such as wound healing, and psychological/social attachment, thereby increasing resilience to subsequent traumatic events. Clinical trials have reported that intranasal administration of OT provides therapeutic benefits for patients diagnosed with traumatic stress-related diseases such as major depressive disorders and post-traumatic stress disorder. OT's therapeutic benefits may result from context-dependent interactions with key neural pathways (social, cognitive, and reward), neurotransmitters (dopamine, norepinephrine, serotonin, and endogenous opioids), and biomarkers (adrenocorticotropic hormone, cortisol, and dehydroepiandrosterone sulfate), that lead to a decrease in stress -associated behaviors, and facilitate post-traumatic growth, ultimately leading to increased resilience, through improved social cohesion and attachment. OT induced-augmentation of physical and cognitive resilience may play a significant role in both the prevention of, and improved clinical outcomes for, traumatic stress-related disorders following either acute or enduring traumatic experiences.

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.

A tumultuous transition to motherhood: Altered brain and hormonal responses in mothers with postpartum depression

Postpartum depression (PPD) is a common but complex condition that is poorly understood and multifactorial in aetiology. It is a condition that can compromise the mother's care for her infant, which may pose challenges to the formation of the mother-infant bond and the infant's overall development. Past research has looked at abnormalities in the brain circuitry and hormonal profiles of mothers with PPD compared to non-depressed mothers. However, abnormalities in PPD that may specifically affect the mother's care of her infant have not been clearly assessed. Thus, the present review aims to synthesise studies of altered brain and hormonal responses in mothers with PPD in relation to their care of their infant. First, we review maternal brain responses and their relation to PPD symptomatology, focusing on the salience/fear network, reward/attachment network and default mode network. Next, we discuss oxytocin and hypothalamic-pituitary-adrenal axis hormones in the context of maternal behaviour and PPD. Finally, we synthesise these findings and propose how future studies may benefit from the combined study of both neural and hormonal activity to better understand the underlying neurobiology of maternal care in PPD.

Early Life Adversity and Adult Social Behavior: Focus on Arginine Vasopressin and Oxytocin as Potential Mediators

Exposure to stress during the early postnatal period (i.e., early life stress, ES) can impact brain physiology and modify individual variability in adult social behavior. Arginine vasopressin (AVP) and oxytocin (OXT) are two centrally released neuropeptides that are involved in shaping essential social behaviors, like aggression, social recognition, and social motivation. AVP and OXT modulate activity in brain regions important for the establishment of social behavior, and may be particularly sensitive to ES. In this review, we discuss whether ES alters the characteristics of the AVP- and OXT- systems in rodents, and whether these changes are associated with later alterations in aggression, social recognition, and social motivation. We have integrated causal studies indicating that (1) ES affects AVP/OXT, and (2) that changing AVP/OXT in affected regions alters social behavior. Although there is encouraging evidence that ES causes AVP- and OXT-system changes, and that these may mediate social behavior, a comprehensive understanding of the exact nature of AVP- and OXT changes and whether they are causal in establishing these behavioral disturbances needs further investigation. As there are indications that ES alters AVP- and OXT characteristics in humans as well, and that these may interact with adult predisposition to psychopathology with social dysfunction, future rodent studies may lay ground for a better understanding of such changes in humans. Ultimately, this may assist in developing therapeutic strategies to target ES effects on social behavior.

The Role of Intranasal Oxytocin in Anxiety and Depressive Disorders: A Systematic Review of Randomized Controlled Trials

Several studies have demonstrated the neuromodulating function of oxytocin (OT) in response to anxiogenic stimuli as well as its potential role in the pathogenesis of depression. Consequently, intranasal OT (IN-OT) has been proposed as a potential treatment of anxiety and depressive disorders. The present systematic review aimed to summarize the randomized controlled trials (RCTs) evaluating the effect of IN-OT on anxiety and depressive symptoms. Overall, 15 studies were included, involving patients with social anxiety disorders (7 studies), arachnophobia (1), major depression (3) or post-natal depression (4), and mainly evaluating single-dose administrations of IN-OT. Results showed no significant effects on core symptomatology. Five crossover studies included functional magnetic resonance imaging investigation: one trial showed reduced amygdala hyper-reactivity after IN-OT in subjects with anxiety, while another one showed enhanced connectivity between amygdala and bilateral insula and middle cingulate gyrus after IN-OT in patients but not in healthy controls. More studies are needed to confirm these results. In conclusion, up to date, evidence regarding the potential utility of IN-OT in treating anxiety and depression is still inconclusive. Further RCTs with larger samples and long-term administration of IN-OT are needed to better elucidate its potential efficacy alone or in association with standard care.

Oxytocin as Treatment for Social Cognition, Not There Yet

In a short time, oxytocin has progressed from being a regular hormone involved in parturition and breastfeeding to be possibly the neuromodulator that has gathered the most attention. Attributed many positive roles in the modulation of different aspects of social behavior, such as bonding, empathy, cooperation, trust, and generosity, as well as roles as a natural anxiolytic and antidepressant, the expectations on oxytocin becoming a treatment for a number of disorders with associated social deficits have dramatically raised over the last years. However, despite the field has been investigating oxytocin's role in social behavior for over twenty years, there are still many unknowns on oxytocin's mechanisms of action and efficiency and the increasing number of clinical trials administering oxytocin to different clinical groups seem to disagree in its properties and report in most cases conflicting results. This has led to some disappointment among researchers and clinicians as oxytocin might not be the miraculous molecule that works in a "one size fits all" fashion initially considered. Conversely, this down-side of oxytocin might merely reflect the complexity of its neurotransmission system. The current reality is that, although oxytocin seems to have potential therapeutic value, there are key questions that remain unanswered as to decide the optimal target groups and treatment course. Here, we present an overview on critical points regarding the oxytocin system in health and disease that need to be better understood to establish its therapeutic properties and to decide who could benefit the most from its treatment.

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.

Treatment of neurocognitive symptoms in unipolar depression: A systematic review and future perspectives

BACKGROUND

Cognitive symptoms in Major Depressive Disorder (MDD) are persistent and commonly entail neurocognitive impairment and a decline in quality of life. This systematic review gathers the current scientific evidence on therapeutic strategies for neuropsychological impairment in MDD.

METHOD

A systematic search on PubMed, PsycINFO and Clinicaltrials.gov was carried out on December 2016 according to PRISMA using Boolean terms to identify interventions for the treatment of cognitive dysfunction in MDD. Only English-written articles providing original data and focusing in adults with MDD were included with no time restrictions.

RESULTS

A total of 95 studies reporting data on 40 pharmacological and non-pharmacological interventions were included. Interventions were grouped into the following categories: 1) Pharmacological Therapies (antidepressants, stimulants, compounds acting on NMDA receptors, compounds acting on the cholinergic system, compounds showing anti-inflammatory or antioxidant properties, other mechanisms of action), 2) Physical Therapies and 3) Psychological Therapies, 4) Exercise. There are some promising compounds showing a positive impact on cognitive symptoms including vortioxetine, lisdexamfetamine or erythropoietin.

LIMITATIONS

The studies included showed significant methodological differences in heterogeneous samples. The lack of a standardized neuropsychological battery makes comparisons between studies difficult.

CONCLUSION

Current evidence is not sufficient to widely recommend the use of procognitive treatments in MDD although promising results are coming to light.

Sex-dependent neural effect of oxytocin during subliminal processing of negative emotion faces

In line with animal models indicating sexually dimorphic effects of oxytocin (OXT) on social-emotional processing, a growing number of OXT-administration studies in humans have also reported sex-dependent effects during social information processing. To explore whether sex-dependent effects already occur during early, subliminal, processing stages the present pharmacological fMRI-study combined the intranasal-application of either OXT or placebo (n = 86-43 males) with a backward-masking emotional face paradigm. Results showed that while OXT suppressed inferior frontal gyrus, dorsal anterior cingulate and anterior insula responses to threatening face stimuli in men it increased them in women. In women increased anterior cingulate reactivity during subliminal threat processing was also positively associated with trait anxiety. On the network level, sex-dependent effects were observed on amygdala, anterior cingulate and inferior frontal gyrus functional connectivity that were mainly driven by reduced coupling in women following OXT. Our findings demonstrate that OXT produces sex-dependent effects even at the early stages of social-emotional processing, and suggest that while it attenuates neural responses to threatening social stimuli in men it increases them in women. Thus in a therapeutic context OXT may potentially produce different effects on anxiety disorders in men and women.

Oxytocin differentially alters resting state functional connectivity between amygdala subregions and emotional control networks: Inverse correlation with depressive traits

The hypothalamic neuropeptide oxytocin (OT) has received increasing attention for its role in modulating social-emotional processes across species. Previous studies on using intranasal-OT in humans point to a crucial engagement of the amygdala in the observed neuromodulatory effects of OT under task and rest conditions. However, the amygdala is not a single homogenous structure, but rather a set of structurally and functionally heterogeneous nuclei that show distinct patterns of connectivity with limbic and frontal emotion-processing regions. To determine potential differential effects of OT on functional connectivity of the amygdala subregions, 79 male participants underwent resting-state fMRI following randomized intranasal-OT or placebo administration. In line with previous studies OT increased the connectivity of the total amygdala with dorso-medial prefrontal regions engaged in emotion regulation. In addition, OT enhanced coupling of the total amygdala with cerebellar regions. Importantly, OT differentially altered the connectivity of amygdala subregions with distinct up-stream cortical nodes, particularly prefrontal/parietal, and cerebellar down-stream regions. OT-induced increased connectivity with cerebellar regions were largely driven by effects on the centromedial and basolateral subregions, whereas increased connectivity with prefrontal regions were largely mediated by right superficial and basolateral subregions. OT decreased connectivity of the centromedial subregions with core hubs of the emotional face processing network in temporal, occipital and parietal regions. Preliminary findings suggest that effects on the superficial amygdala-prefrontal pathway were inversely associated with levels of subclinical depression, possibly indicating that OT modulation may be blunted in the context of increased pathological load. Together, the present findings suggest a subregional-specific modulatory role of OT on amygdala-centered emotion processing networks in humans.

Oxytocin and Stress-related Disorders: Neurobiological Mechanisms and Treatment Opportunities

Novel pharmacotherapies that improve outcomes for individuals with stress-related psychiatric disorders are needed. The neurohormone oxytocin (OT) is a promising candidate given its influence on the social-emotional brain. In this review, we present an overview of evidence supporting OT's utility for treating major depressive disorder and posttraumatic stress disorder. We first discuss endogenous OT, which research suggests is not yet a reliable biomarker of stress-related disorders. Second, we review effects of intranasal (IN) OT on processes relevant to stress-related disorders in healthy populations (anhedonia, reward processing, psychosocial stress reactivity, fear/anxiety, and social behavior) and their neurobiological mechanisms (e.g., the salience network and hypothalamic-pituitary-adrenal axis). Third, we present the sparse but promising findings from clinical populations, followed by discussion of critical moderating variables to consider in the service of maximizing the therapeutic potential of OT (e.g., patient sex and child maltreatment). We also identify heterogeneous findings and limitations of existing research, including reliance on single-dose studies in psychiatrically healthy samples and unanswered questions regarding the effectiveness of IN drug delivery and dosing schedules. Well-controlled multidose studies including women and measures of potentially moderating variables are sorely needed and would inform our understanding of the utility of OT for preventing and treating stress-related psychiatric disorders.

Oxytocin and Facial Emotion Recognition

The expression of emotion in faces serves numerous meaningful functions, such as conveying messages of danger or approach, facilitating communication, and promoting the formation of social bonds and relationships. The study of facial expressions of emotion has become integral to research in social psychology and social neuroscience, particularly with respect to the neuropeptide oxytocin. This chapter examines how oxytocin influences the processing of emotion in faces by reviewing intranasal administration studies of automatic processing, selective attention, and emotion recognition. Two important trends in the literature have been identified: exogenous oxytocin attenuates early attentional biases towards negative stimuli and increases selective attention and recognition of emotional cues in faces, particularly around the eyes. Both of these effects can be traced to well-delineated neural circuits involving amygdala, early visual processing areas, and reward circuits, and both purportedly facilitate approach-related behavior when affiliative opportunities are available. These data are integrated into a conceptual model incorporating contextual factors and moderating influences, as oxytocinergic effects on cognition and social behavior appear to vary in persons along indices of social competence, interpersonal sensitivity, and early adversity. Limitations of this literature and future directions for research are briefly discussed.

Oxytocin in the socioemotional brain: implications for psychiatric disorders

The neuropeptide oxytocin (OXT), highly conserved during evolution, is an important modulator of social and emotional processes across many species. During the last decade, a large body of literature has revealed its effects on different aspects of social behavior, including social stress and anxiety, social memory, affiliation and bonding, emotion recognition, mentalizing, empathy, and interpersonal trust. In addition, as impairments in these social domains can be observed in a number of neuropsychiatric disorders, such as autism, social anxiety disorder, depression, schizophrenia, and borderline personality disorder, the role of OXT in mental disorders and their treatment has been intensively studied. The present paper gives a short overview of these lines of research and shows how OXT has become a promising target for novel treatment approaches for mental disorders characterized by social impairments.

The Role of Oxytocin in Parenting and as Augmentative Pharmacotherapy: Critical Issues and Bold Conjectures

Despite the sometimes heated debate about the validity of human oxytocin studies, experimental oxytocin research with intranasal administration is a growing field with promising preliminary findings. The effects of intranasally administered oxytocin compared to placebo on brain neural activity have been supported in animal studies and in human studies of neural resting state. In several studies, oxytocin sniffs have been shown to lead to down-regulation of amygdala activation in response to infant attachment vocalisations. Meta-analytic evidence shows that oxytocin enhances the salience of (emotional) stimuli, lowers stress and arousal, and elevates empathic concern and tender care, in particular for offspring and in-group members. Less firm evidence points at the amnestic effects of oxytocin. We also note that the average effect sizes of oxytocin experiments are small to modest, and that most studies include a small number of subjects and thus are seriously underpowered, which implies a high risk for publication bias and nonreplicability. Nevertheless, we argue that the power of within-subjects experiments with oxytocin has been underestimated. Much more work is needed, however, to create a firm knowledge base of the neural and behavioural effects of oxytocin. Human oxytocin research is still taking place in the context of discovery, in which bold conjectures are being generated. In the context of justification, these conjectures should subsequently be subjected to stringent attempts at refutations before we jump to theoretical or clinical conclusions. For this context of justification, we propose a multisite multiple replications project on the social stimuli salience enhancing effect of oxytocin. Clinical application of oxytocin is premature. Meta-analytically, the use of oxytocin in clinical groups tends to show only effectiveness in changing symptomatology in individuals with autism spectrum disorders but, even then, it is not yet a validated therapy and its use is premature because safety and long-term side-effects have not been sufficiently studied, in particular in children.

Social functioning in major depressive disorder

Depression is associated with social risk factors, social impairments and poor social functioning. This paper gives an overview of these social aspects using the NIMH Research and Domain Criteria 'Systems for Social Processes' as a framework. In particular, it describes the bio-psycho-social interplay regarding impaired affiliation and attachment (social anhedonia, hyper-sensitivity to social rejection, competition avoidance, increased altruistic punishment), impaired social communication (impaired emotion recognition, diminished cooperativeness), impaired social perception (reduced empathy, theory-of-mind deficits) and their impact on social networks and the use of social media. It describes these dysfunctional social processes at the behavioural, neuroanatomical, neurochemical and genetic levels, and with respect to animal models of social stress. We discuss the diagnostic specificity of these social deficit constructs for depression and in relation to depression severity. Since social factors are importantly involved in the pathogenesis and the consequences of depression, such research will likely contribute to better diagnostic assessments and concepts, treatments and preventative strategies both at the diagnostic and transdiagnostic level.

Memory response to oxytocin predicts relationship dissolution over 18 months

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

A Spatiotemporal Profile of In Vivo Cerebral Blood Flow Changes Following Intranasal Oxytocin in Humans

BACKGROUND

Animal and human studies highlight the role of oxytocin in social cognition and behavior and the potential of intranasal oxytocin (IN-OT) to treat social impairment in individuals with neuropsychiatric disorders such as autism. However, extensive efforts to evaluate the central actions and therapeutic efficacy of IN-OT may be marred by the absence of data regarding its temporal dynamics and sites of action in the living human brain.

METHODS

In a placebo-controlled study, we used arterial spin labeling to measure IN-OT-induced changes in resting regional cerebral blood flow (rCBF) in 32 healthy men. Volunteers were blinded regarding the nature of the compound they received. The rCBF data were acquired 15 min before and up to 78 min after onset of treatment onset (40 IU of IN-OT or placebo). The data were analyzed using mass univariate and multivariate pattern recognition techniques.

RESULTS

We obtained robust evidence delineating an oxytocinergic network comprising regions expected to express oxytocin receptors, based on histologic evidence, and including core regions of the brain circuitry underpinning social cognition and emotion processing. Pattern recognition on rCBF maps indicated that IN-OT-induced changes were sustained over the entire posttreatment observation interval (25-78 min) and consistent with a pharmacodynamic profile showing a peak response at 39-51 min.

CONCLUSIONS

Our study provides the first visualization and quantification of IN-OT-induced changes in rCBF in the living human brain unaffected by cognitive, affective, or social manipulations. Our findings can inform theoretical and mechanistic models regarding IN-OT effects on typical and atypical social behavior and guide future experiments (e.g., regarding the timing of experimental manipulations).

Effects of oxytocin and genetic variants on brain and behaviour: Implications for treatment in schizophrenia

Impairments in social cognition and poor social functioning are core features of schizophrenia-spectrum disorders. In recent years, there has been a move towards developing new treatment strategies that specifically target social cognitive and social behavioural deficits. Oxytocin (OXT) is one such strategy that has gained increasing attention. There is a strong rationale for studying OXT in psychosis, from both an evolutionary perspective and neurodevelopmental-cognitive model of schizophrenia. Thus, the aim of this review was to critique and examine the observational and clinical oxytocin trial literature in schizophrenia-spectrum disorders. A handful of clinical trials suggest that OXT treatment may be beneficial for remediating social cognitive impairments, psychiatric symptoms, and improving social outcomes. However, inconsistencies exist in this literature, which may be explained by individual differences in the underlying neural response to OXT treatment and/or variation in the oxytocin and oxytocin receptor genes. Therefore, we additionally reviewed the evidence for structural and functional neural intermediate phenotypes in humans that link genetic variants to social behaviour/thinking, and discuss the implications of such interactions in the context of dysfunctional brain networks in schizophrenia. Factors that pose challenges for future OXT clinical research include the impact of age, sex, and ancestry, task-specific effects, bioavailability and pharmacokinetics, as well as neurotransmitter and drug interactions. While initial findings from OXT single dose/clinical trial studies are promising, more interdisciplinary research in both healthy and psychiatric populations is needed before determining whether OXT is a viable treatment option/adjunct for addressing poor illness outcomes in psychotic disorders.

Does oxytocin affect mind-reading? A replication study

One of the most well-known findings in human oxytocin research is its beneficial effect on "mind-reading", i.e., inferring others' mental states just from the eye region in the Reading the Mind in the Eyes Test (RMET). Previous studies have partially confirmed these improvements and have further shown that they depend both on baseline social-emotional abilities and on specific item characteristics such as difficulty. Following the original design of Domes et al. (2007), the aim of the current study was to replicate and extend previous findings by thoroughly investigating the impact of oxytocin administration on RMET performance. We tested for potential moderation effects involving item difficulty, valence, intensity, sex of poser as well as individual differences in trait empathy measured with the Empathy Quotient (EQ) for a general score and the Interpersonal Reactivity Index (IRI) for a multidimensional assessment of cognitive and emotional empathy. Oxytocin did not affect mind-reading, neither in general nor when considering specific item characteristics. An association between oxytocin-induced changes in RMET performance and emotional empathy (the empathic concern scale of the IRI) was evident, with individuals low in emotional empathy showing greater improvement after oxytocin administration compared to placebo. The reproducibility and variability of these and prior findings needs to be addressed in future experiments. As true effects may not replicate across different studies for various reasons, this should not discourage, but encourage further research.

MATERNAL DEPRESSION AND CHILD OXYTOCIN RESPONSE; MODERATION BY MATERNAL OXYTOCIN AND RELATIONAL BEHAVIOR

BACKGROUND

Maternal postpartum depression (PPD) carries long-term detrimental effects on children's well-being, yet the mechanisms of transmission remain unclear. One possible pathway of vulnerability involves the oxytocinergic (OT) system, which is transferred from mother to child via sensitive caregiving and is disrupted in PPD.

METHOD

A large birth cohort (N = 1983) of women were repeatedly assessed for depression from birth to 6 years. Utilizing an extreme case design, two matched cohorts were formed; mothers chronically depressed from birth to 6 years and nondepressed controls (N = 97, depressed = 41, nondepressed; N = 56). At 6 years, mothers and children underwent psychiatric diagnosis, urinary OT was assayed from mother and child before and after social contact, and mother-child interactions were coded.

RESULTS

Baseline OT and OT response of mother and child were interrelated and children of depressed mothers showed low baseline OT and attenuated OT response. Child OT response was negatively predicted by maternal depression, child Axis-I psychopathology, maternal expressed negative affect, and child social withdrawal. Interaction effect of maternal baseline OT and depression emerged. Slope analysis indicated that when maternal OT was medium or low, child OT response was negatively impacted by maternal depression. However, when maternal OT was high, child OT was unaffected, suggesting that maternal OT functionality buffers the effects of depression on the child.

CONCLUSION

Results suggest involvement of the OT system in the cross-generational transfer of vulnerability, as well as resilience, from depressed mothers to their children. Because the OT system is open to interventions that enhance maternal touch and contact, findings have important implications for targeted early dyadic inventions.

Oxytocin affects spontaneous neural oscillations in trauma-exposed war veterans

Exposure to combat-related trauma often leads to lifetime functional impairments. Previous research demonstrated the effects of oxytocin (OT) administration on brain regions implicated in post-traumatic stress disorder (PTSD); yet OT’s effects on brain patterns in trauma-exposed veterans have not been studied. In the current study the effects of OT on spontaneous brain oscillatory activity were measured in 43 veterans using magnetoencephalography (MEG): 28 veterans who were exposed to a combat-related trauma and 15 trauma-unexposed controls. Participants participated in two experimental sessions and were administered OT or placebo (PBO) in a double-blind, placebo-control, within-subject design. Following OT/PBO administration, participants underwent a whole-head MEG scan. Plasma and salivary OT levels were assessed each session. Spontaneous brain activity measured during a 2-min resting period was subjected to source-localization analysis. Trauma-exposed veterans showed higher resting-state alpha (8–13 Hz) activity compared to controls in the left dorsolateral prefrontal cortex (dlPFC), specifically in the superior frontal gyrus (SFG) and the middle frontal gyrus (MFG), indicating decreased neural activity in these regions. The higher alpha activity was “normalized” following OT administration and under OT, group differences were no longer found. Increased resting-state alpha was associated with lower baseline plasma OT, reduced salivary OT reactivity, and more re-experiencing symptoms. These findings demonstrate effects of OT on resting-state brain functioning in prefrontal regions subserving working memory and cognitive control, which are disrupted in PTSD. Results raise the possibility that OT, traditionally studied in social contexts, may also enhance performance in cognitive tasks associated with working memory and cognitive control following trauma exposure.

Methylation of the oxytocin receptor gene in clinically depressed patients compared to controls: The role of OXTR rs53576 genotype

The emerging field of epigenetics provides a biological basis for gene-environment interactions relevant to depression. We focus on DNA methylation of exon 1 and 2 of the oxytocin receptor gene (OXTR) promoter. The research aims of the current study were to compare OXTR DNA methylation of depressed patients with healthy control subjects and to investigate possible influences of the OXTR rs53576 genotype. The sample of the present study consisted of 43 clinically depressed women recruited from a psychosomatic inpatient unit and 42 healthy, female control subjects - mean age 30 years (SD = 9). DNA methylation profiles of the OXTR gene were assessed from leukocyte DNA by means of bisulfite sequencing. Depressed female patients had decreased OXTR exon 1 DNA methylation compared to non-depressed women. The association between depression and methylation level was moderated by OXTR rs53576 genotype. Exon 2 methylation was associated with OXTR rs53576 genotype but not with depression. Our findings suggest exon-specific methylation mechanisms. Exon 1 methylation appears to be associated with depressive phenotypes whereas exon 2 methylation is influenced by genotype. Previously reported divergent associations between OXTR genotype and depression might be explained by varying exon 1 methylation. In order to further understand the etiology of depression, research on the interplay between genotype, environmental influences and exon-specific methylation patterns is needed.

Cognition as a target in major depression: new developments

Major depressive disorder (MDD) is a highly prevalent and disabling psychiatric illness often accompanied of cognitive dysfunction which may persist even when patients achieve clinical remission. Currently, cognitive deficits emerge as a potential target because they compromise the functional outcome of depressed patients. The aim of this study was to review data for several potential pharmacological treatments targeting cognition in MDD, resulting from monotherapy or adjunctive treatment. An extensive and systematic Pubmed/Medline search of the published literature until March 2014 was conducted using a variety of search term to find relevant articles. Bibliographies of retrieved papers were further examined for publications of interest. Searches were limited to articles available in English language. We describe studies using modafinil, lisdexamfetamine, ketamine, lanicemine, memantine, galantamine, donepezil, vortioxetine, intranasal oxytocin, omega-3, s-adenosyl-methionine, scopolamine and erythropoietin. From these articles, we determined that there are a number of promising new therapies, pharmacological agents or complementary medicines, but data are just emerging. Drugs and therapies targeting cognitive dysfunction in MDD should prove effective in improving specific cognitive domains and functioning, while ruling out pseudospecificity.

Oxytocin increases eye contact during a real-time, naturalistic social interaction in males with and without autism

Autism spectrum conditions (autism) affect ~1% of the population and are characterized by deficits in social communication. Oxytocin has been widely reported to affect social-communicative function and its neural underpinnings. Here we report the first evidence that intranasal oxytocin administration improves a core problem that individuals with autism have in using eye contact appropriately in real-world social settings. A randomized double-blind, placebo-controlled, within-subjects design is used to examine how intranasal administration of 24 IU of oxytocin affects gaze behavior for 32 adult males with autism and 34 controls in a real-time interaction with a researcher. This interactive paradigm bypasses many of the limitations encountered with conventional static or computer-based stimuli. Eye movements are recorded using eye tracking, providing an objective measurement of looking patterns. The measure is shown to be sensitive to the reduced eye contact commonly reported in autism, with the autism group spending less time looking to the eye region of the face than controls. Oxytocin administration selectively enhanced gaze to the eyes in both the autism and control groups (transformed mean eye-fixation difference per second=0.082; 95% CI:0.025-0.14, P=0.006). Within the autism group, oxytocin has the most effect on fixation duration in individuals with impaired levels of eye contact at baseline (Cohen's d=0.86). These findings demonstrate that the potential benefits of oxytocin in autism extend to a real-time interaction, providing evidence of a therapeutic effect in a key aspect of social communication.

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

BACKGROUND

Oxytocin (OXT) plays a prominent role in social cognition and may have clinical applications for disorders such as autism, schizophrenia and social anxiety. The neural basis of its mechanism of action remains unclear.

METHODS

We conducted a systematic literature review of placebo-controlled imaging studies using OXT as a pharmacological manipulator of brain activity.

RESULTS

We identified a total of 21 studies for inclusion in our review, and after applying additional selection criteria, 11 of them were included in our fMRI voxel-based meta-analysis. The results demonstrate consistent alterations in activation of brain regions, including the temporal lobes and insula, during the processing of social stimuli, with some variation dependent on sex and task. The meta-analysis revealed significant left insular hyperactivation after OXT administration, suggesting a potential modulation of neural circuits underlying emotional processing.

LIMITATIONS

This quantitative review included only a limited number of studies, thus the conclusions of our analysis should be interpreted cautiously. This limited sample size precluded a more detailed exploration of potential confounding factors, such as sex or other demographic factors, that may have affected our meta-analysis.

CONCLUSION

Oxytocin has a wide range of effects over neural activity in response to social and emotional processing, which is further modulated by sex and task specificity. The magnitude of this neural activation is largest in the temporal lobes, and a meta-analysis across all tasks and both sexes showed that the left insula demonstrated the most robust activation to OXT administration.

Neurofunctional maps of the 'maternal brain' and the effects of oxytocin: a multimodal voxel-based meta-analysis

Several studies have tried to understand the possible neurobiological basis of mothering. The putative involvement of oxytocin, in this regard, has been deeply investigated. Performing a voxel-based meta-analysis, we aimed at testing the hypothesis of overlapping brain activation in functional magnetic resonance imaging (fMRI) studies investigating the mother-infant interaction and the oxytocin modulation of emotional stimuli in humans. We performed two systematic literature searches: fMRI studies investigating the neurofunctional correlates of the 'maternal brain' by employing mother-infant paradigms; and fMRI studies employing oxytocin during emotional tasks. A unimodal voxel-based meta-analysis was performed on each database, whereas a multimodal voxel-based meta-analytical tool was adopted to assess the hypothesis that the neurofunctional effects of oxytocin are detected in brain areas implicated in the 'maternal brain.' We found greater activation in the bilateral insula extending to the inferior frontal gyrus, basal ganglia and thalamus during mother-infant interaction and greater left insular activation associated with oxytocin administration versus placebo. Left insula extending to basal ganglia and frontotemporal gyri as well as bilateral thalamus and amygdala showed consistent activation across the two paradigms. Right insula also showed activation across the two paradigms, and dorsomedial frontal cortex activation in mothers but deactivation with oxytocin. Significant activation in areas involved in empathy, emotion regulation, motivation, social cognition and theory of mind emerged from our multimodal meta-analysis, supporting the need for further studies directly investigating the neurobiology of oxytocin in the mother-infant relationship.

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

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

[Oxytocin: evidence for a therapeutic potential of the social neuromodulator]

Only few substances have achieved such a great prominence in recent years as the hypothalamic neuropeptide oxytocin, which is also widely known as the love hormone. Oxytocin is a potent neuromodulator which can improve social cognitive functions including empathy, trust, cooperation and social learning. However, oxytocin can also promote negative social behavior and increase poor memory and feelings of fear in social situations. Positive data from initial clinical trials give rise to the hope that oxytocin will prove to be a substance which is suitable for targeted treatment of poor social-cognitive behavior in neuropsychiatric diseases. This review article summarizes the most important recent preclinical and clinical human studies and discusses the findings presented with respect to current concepts of personal and contextual influences.

Oxytocin effects on mind-reading are moderated by experiences of maternal love withdrawal: an fMRI study

The neuropeptide oxytocin has been shown to stimulate a range of social behaviors. However, recent studies indicate that the effects of intranasal oxytocin are more nuanced than previously thought and that contextual factors and individual characteristics moderate the beneficiary oxytocin effects. In this randomized-controlled trial we examine the influence of intranasally administered oxytocin on neural activity during mind-reading with fMRI, taking into account harsh caregiving experiences as a potential moderator. Participants were 50 women who received a nasal spray containing either 16 IU of oxytocin or a placebo and had reported how often their mother used love withdrawal as a disciplinary strategy. Participants performed an adapted version of the Reading the Mind in the Eyes Test (RMET), a task which requires individuals to infer mental states by looking at photographs of the eye region of faces. We found that oxytocin enhanced neural activation in the superior temporal gyrus (STG) and insula during the RMET. Moreover, oxytocin increased RMET performance outside the scanner. However, the oxytocin induced changes in STG activation and RMET performance were only brought about in potentially less socially proficient individuals who had low RMET performance, that is, participants reporting higher levels of maternal love withdrawal.

Early life stress modulates amygdala-prefrontal functional connectivity: implications for oxytocin effects

Recent evidence suggests that early life stress (ELS) changes stress reactivity via reduced resting state functional connectivity (rs-FC) between amygdala and the prefrontal cortex. Oxytocin (OXT) modulates amygdala connectivity and attenuates responses to psychosocial stress, but its effect appears to be moderated by ELS. Here we first investigate the effect of ELS on amygdala-prefrontal rs-FC, and examine whether ELS-associated changes of rs-FC in this neural circuit predict its response to psychosocial stress. Secondly, we explore the joint effect of OXT and ELS on the amygdala-prefrontal circuit. Eighteen healthy young males participated in a resting-state fMRI study of OXT effects using a double-blind, randomized, placebo-controlled, within-subject crossover design. We measured the rs-FC to bilateral amygdalae and subsequently assessed changes of state anxiety and prefrontal responses to psychosocial stress. Multiple linear regressions showed that ELS, specifically emotional abuse, predicted reduced rs-FC between the right amygdala and pregenual anterior cingulate cortex (pgACC), which in turn predicted elevated state anxiety after psychosocial stress. In subjects with lower ELS scores, stronger pgACC-amygdala rs-FC predicted stronger pgACC deactivation during the psychosocial stress task, and this rest-task interaction was attenuated by OXT. In subjects with higher ELS scores however, the rest-task interaction was altered and OXT showed no significant effect. These findings highlight that ELS reduces pgACC-amygdala rs-FC and alters how rs-FC of this circuit predicts its stress responsiveness. Such changes in pgACC-amygdala functional dynamics may underlie the altered sensitivity to the effects of OXT after ELS.