Oxytocin Pathway Genes: Evolutionary Ancient System Impacting on Human Affiliation, Sociality, and Psychopathology

Emotional contagion and prosocial behaviour in fish: An evolutionary and mechanistic approach

In this review, we consider the definitions and experimental approaches to emotional contagion and prosocial behaviour in mammals and explore their evolutionary conceptualisation for studying their occurrence in the evolutionarily divergent vertebrate group of ray-finned fish. We present evidence for a diverse set of fish phenotypes that meet definitional criteria for prosocial behaviour and emotional contagion and discuss conserved mechanisms that may account for some preserved social capacities in fish. Finally, we provide some considerations on how to address the question of interdependency between emotional contagion and prosocial response, highlighting the importance of recognition processes, decision-making systems, and ecological context for providing evolutionary explanations.

From molecular variations to behavioral adaptations: Unveiling adaptive epistasis in primate oxytocin system

OBJECTIVE

Our primary objective was to investigate the variability of oxytocin (OT) and the GAMEN binding motif within the LNPEP oxytocinase in primates.

MATERIALS AND METHODS

We sequenced the LNPEP segment encompassing the GAMEN motif in 34 Platyrrhini species, with 21 of them also sequenced for the OT gene. Our dataset was supplemented with primate sequences of LNPEP, OT, and the oxytocin receptor (OTR) sourced from public databases. Evolutionary analysis and coevolution predictions were made followed by the macroevolution analysis of relevant amino acids associated with phenotypic traits, such as mating systems, parental care, and litter size. To account for phylogenetic structure, we utilized two distinct statistical tests. Additionally, we calculated binding energies focusing on the interaction between Callithtrix jacchus VAMEN and Pro8OT.

RESULTS

We identified two novel motifs (AAMEN and VAMEN), challenging the current knowledge of motif conservation in placental mammals. Coevolution analysis demonstrated a correlation between GAMEN, AAMEN, and VAMEN and their corresponding OTs and OTRs. Callithrix jacchus exhibited a higher binding energy between VAMEN and Pro8OT than orthologous molecules found in humans (GAMEN and Leu8OT).

DISCUSSION

The coevolution of AAMEN and VAMEN with their corresponding OTs and OTRs suggests a functional relationship that could have contributed to specific reproductive and adaptive behaviors, including paternal care, social monogamy, and twin births, prominent traits in Cebidae species, such as marmosets and tamarins. Our findings underscore the coevolution of taxon-specific amino acids among the three studied molecules, shedding light on the oxytocinergic system as an adaptive epistatic repertoire in primates.

The effects of oxytocin administration on social and routinized behaviors in autism: A preregistered systematic review and meta-analysis

Oxytocin administration has demonstrated considerable promise for providing individualized support for autistic people. However, studies evaluating the effects of oxytocin administration on autistic characteristics have yielded inconsistent results. This systematic review and meta-analysis investigates the effect of oxytocin administration on social and routinized behaviors in autism using recently developed methods to accurately assess the potential impact of effect size dependency and publication bias. Our frequentist meta-analysis yielded a significant summary effect size estimate for the impact of oxytocin administration on social outcomes in autism (d = 0.22, p < 0.001). The summary effect size estimate for routinized behavior outcomes was not statistically significant (d = 0.14, p = 0.22), with a follow up test indicating that the effect size estimate was not either statistically equivalent (Z = -1.06, p = 0.2), assuming a smallest effect size of interest of 0.25. Frequentist and Bayesian assessments for publication bias, as well as results from Robust Bayesian meta-analysis of oxytocin effects on social outcomes in autism, indicated that summary effect sizes might be inflated due to publication bias. Future studies should aim to reduce bias by preregistering analysis plans and to increase precision with larger sample sizes.

Patterns of neural activity in response to threatening faces are predictive of autistic traits: modulatory effects of oxytocin receptor genotype

Autistic individuals generally demonstrate impaired emotion recognition but it is unclear whether effects are emotion-specific or influenced by oxytocin receptor (OXTR) genotype. Here we implemented a dimensional approach using an implicit emotion recognition task together with functional MRI in a large cohort of neurotypical adult participants (N = 255, male = 131, aged 17-29 years) to establish associations between autistic traits and neural and behavioral responses to specific face emotions, together with modulatory effects of OXTR genotype. A searchlight-based multivariate pattern analysis (MVPA) revealed an extensive network of frontal, basal ganglia, cingulate and limbic regions exhibiting significant predictability for autistic traits from patterns of responses to angry relative to neutral expression faces. Functional connectivity analyses revealed a genotype interaction (OXTR SNPs rs2254298, rs2268491) for coupling between the orbitofrontal cortex and mid-cingulate during angry expression processing, with a negative association between coupling and autistic traits in the risk-allele group and a positive one in the non-risk allele group. Overall, results indicate extensive emotion-specific associations primarily between patterns of neural responses to angry faces and autistic traits in regions processing motivation, reward and salience but not in early visual processing. Functional connections between these identified regions were not only associated with autistic traits but also influenced by OXTR genotype. Thus, altered patterns of neural responses to threatening faces may be a potential biomarker for autistic symptoms although modulatory influences of OXTR genotype need to be taken into account.

CD38 genetic variation is associated with increased personal distress to an emotional stimulus

Genetic variation in CD38-a putative oxytocin pathway gene-has been linked to higher oxytocin levels, empathy, and sensitive parenting, but also to more negative interpersonal outcomes (e.g., alienation from friends and family, poorer romantic relationship quality). To reconcile these seemingly contradictory findings, we drew upon the idea that CD38 variation may heighten social-emotional sensitivity and, consequently, make individuals prone to negative emotions in distressing interpersonal situations. To test this hypothesis, we performed a secondary analysis of a dataset including participants' (n = 171; 94 females) empathic concern ("sympathetic") and distress-related ("anxious") responses to an emotional video. Distress responses were higher for the CD38 rs3796863 AA/AC group vs. the CC group (p = 0.03, η2 = 0.027); however, there was no significant effect of genotype for empathic concern responses to the video or for indices of trait empathy. These findings provide preliminary evidence that, in the face of an interpersonal stressor, CD38 genetic variation may predict more self-focused, aversive emotional reactions. More broadly, this finding highlights the need to adopt a more nuanced perspective in which the influence of oxytocin system variation (assessed by oxytocin-related genetic variation) should be considered in light of the social context.

Peripheral oxytocin levels are linked to hypothalamic gray matter volume in autistic adults: a cross-sectional secondary data analysis

Oxytocin (OXT) is known to modulate social behavior and cognition and has been discussed as pathophysiological and therapeutic factor for autism spectrum disorder (ASD). An accumulating body of evidence indicates the hypothalamus to be of particular importance with regard to the underlying neurobiology. Here we used a region of interest voxel-based morphometry (VBM) approach to investigate hypothalamic gray matter volume (GMV) in autistic (n = 29, age 36.03 ± 11.0) and non-autistic adults (n = 27, age 30.96 ± 11.2). Peripheral plasma OXT levels and the autism spectrum quotient (AQ) were used for correlation analyses. Results showed no differences in hypothalamic GMV in autistic compared to non-autistic adults but suggested a differential association between hypothalamic GMV and OXT levels, such that a positive association was found for the ASD group. In addition, hypothalamic GMV showed a positive association with autistic traits in the ASD group. Bearing in mind the limitations such as a relatively small sample size, a wide age range and a high rate of psychopharmacological treatment in the ASD sample, these results provide new preliminary evidence for a potentially important role of the HTH in ASD and its relationship to the OXT system, but also point towards the importance of interindividual differences.

Association of verbal and non-verbal theory of mind abilities with non-coding variants of OXTR in youth with autism spectrum disorder and typically developing individuals: a case-control study

BACKGROUND

The ability to attribute mental states to others is called theory of mind (ToM) and is a substantial component of social cognition. This ability is abnormally developed in individuals with autism spectrum disorder (ASD). Several studies over the past decade have identified the oxytocin receptor gene (OXTR) and its variants as promising components for explaining the molecular mechanisms underlying Theory of Mind (ToM). The main aim of this study is to examine the association between rs2268498 and rs53576, two functional single nucleotide polymorphisms (SNPs), and verbal and non-verbal ToM in children and adolescents with ASD and a group of typically developing youth.

METHODS

The study involved 44 children and adolescents with high-functioning ASD aged 8 to 18 years old and 44 TD individuals who were matched on age and sex. In all participants, blood samples were collected and rs2268498 and rs53576 were genotyped. Happe's Strange Stories test and the moving shapes paradigm were used to measure verbal and non-verbal ToM in all participants.

RESULTS

The results of permutation tests and logistic regression suggested that in TD group, rs2268498 AA carriers showed significant higher scores in variables representing verbal ToM (ToM stories and appropriateness score) whereas, in ASD group, rs53576 AA carriers exhibited significant better performance in parameters related to non-verbal ToM (ToM general rule and intentionality score). The results of hierarchical clustering in both groups support the findings by distinguishing between language-related and language-independent aspects of ToM.

CONCLUSIONS

In the present study, we examined the association between rs2268498 and rs53576 and social functioning in individuals with ASD and TD group. We found preliminary evidence that rs2268498 and rs53576 are associated with ToM related abilities in healthy individuals as well as in autistic individuals. Accordingly, rs2268498 and rs53576 may play an important role in predicting ToM capabilities. It will be necessary to conduct further research to address the association of genetic variants with a deficit in ToM in individuals with ASD.

OXTR polymorphisms associated with severity and treatment responses of schizophrenia

The mechanisms generating specific symptoms of schizophrenia remain unclear and genetic research makes it possible to explore these issues at a fundamental level. Taking into account the associations between the oxytocin system and social functions, which are apparently impaired in schizophrenia patients, we hypothesized that the oxytocin receptor gene (OXTR) might be associated with schizophrenia symptoms in both severity and responses to antipsychotics and did this exploratory positional study. A total of 2363 patients with schizophrenia (1181 males and 1182 females) included in our study were randomly allocated to seven antipsychotic treatment groups and received antipsychotic monotherapy for 6 weeks. Their blood DNA was genotyped for OXTR polymorphisms. Their symptom severity was assessed by Positive and Negative Syndrome Scale (PANSS), and the scores were transformed into seven factors (positive, disorganized, negative symptoms apathy/avolition, negative symptoms deficit of expression, hostility, anxiety and depression). Percentage changes in PANSS scores from baseline to week 6 were calculated to quantify antipsychotic responses. We found that OXTR polymorphisms were nominally associated with the severity of overall symptoms (rs237899, β = 1.669, p = 0.019), hostility symptoms (rs237899, β = 0.427, p = 0.044) and anxiety symptoms (rs13316193, β = -0.197, p = 0.038). As for treatment responses, OXTR polymorphisms were nominally associated with the improvement in negative symptoms apathy/avolition (rs2268490, β = 2.235, p = 0.0499). No association between severity or response to treatment and OXTR polymorphisms was found with statistical correction for multiplicity. Overall, our results highlighted the possibility of nominally significant associations of the OXTR gene with the severity and improvement in schizophrenia symptoms. Given the exploratory nature of this study, these associations are indicative of the role of the OXTR gene in the pathology of schizophrenia and may contribute to further elucidate the mechanism of specific symptoms of schizophrenia and to exploit antipsychotics more effective to specific symptoms.

Oxytocin as a transdiagnostic biomarker of well-being in severe mental illness during the Covid-19 pandemic

Individuals with severe mental illness (SMI) have been found to suffer a greater decline in psychological well-being compared to the general population in times of stress. The present study aimed to examine clinical and endocrine resilience factors of psychological well-being in SMI patients during the Covid-19 pandemic.

METHODS

After Covid-19 crisis outburst in Israel 112 participants, 69 outpatients, and 43 inpatients and day treatment patients were recruited. Outpatients signed an online informed consent and filled in questionnaires regarding their level of mental health symptoms (OQ-45), fear of Covid-19 (FCV), and psychological well-being (PWB). Inpatients answered the same questionnaires and in addition, went through a positive social interaction paradigm while providing three saliva samples to measure their s-IgA and oxytocin (OT) levels.

RESULTS

A strong negative correlation was found in the whole sample between reported mental health symptoms, fear of Covid-19, and well-being. Hierarchical regression did not find additional contribution of the fear of the pandemic in predicting well-being beyond the impact of symptomatology. For inpatients (N = 39) only, hierarchical regression found that oxytocin, but not s-IgA could explain 5% of the variance of well-being (R2 = 0.05) in individuals with SMI regardless of their mental health symptoms (R2 = 0.46) and their marital status (R2 = 0.21).

CONCLUSIONS

OT is suggested as a possible independent biological resilience factor of well-being in times of major stress among SMI patients. It is still unknown whether OT is a mediator that contributes to well-being or a biological marker that indicates the degree of beneficial social interactions.

Understanding altruistic behavior: The joint role of prefrontal damage and OXTR genotype

Altruism is a type of prosocial behavior that is carried out in the absence of personal benefit or even at an expense to self. Trait altruism varies greatly across individuals, and the reasons for this variability are still not fully understood. Growing evidence suggests that altruism may be partly determined by the oxytocin receptor (OXTR) gene, which regulates the emotions underlying altruistic attitudes, such as empathy and trust. Neuroimaging and lesion studies have also implied several higher-order brain regions, including the prefrontal cortex, in altruistic behaviors. Yet the existing reports are contradictory and suggest that the top-down control exercised by the prefrontal cortex may promote both altruistic and self-interested behaviors and, thus, could obscure one's natural proclivity towards altruism encoded by OXTR. Here, we hypothesized that extensive prefrontal damage would result in an increased influence of the OXTR genotype on one's altruistic attitudes and actions. To test this hypothesis, we recruited 115 male combat veterans with penetrating traumatic brain injury to the prefrontal cortex and other brain regions, as well as 35 demographically matched control subjects without brain injury. Participants completed a self-report altruism questionnaire and were genotyped for four OXTR single nucleotide polymorphisms implicated in prosocial behavior, including rs53576, rs1042778, rs2254298 and rs7632287. Consistent with the previous studies, we found that individuals homozygotic for the G allele of rs53576 and rs7632287 were significantly more altruistic than carriers of at least one "vulnerable" A allele. Remarkably, in patients with prefrontal cortex damage, greater lesion extent was associated with significantly lower altruism scores in carriers of the A allele of rs7632287, but not in G-homozygotes, suggesting that significant disruption of the prefrontal cortex increased the influence of genetic polymorphisms on prosocial behavior. This study presents the first account of an interaction effect between the OXTR genotype and the location and extent of brain damage.

A long and winding road: My personal journey to oxytocin with no return

The present paper is the personal narration of the author reviewing her scientific pathways that led her toward the study of oxytocin. My work began with a pioneering study showing a decreased number of the serotonin transporter proteins in romantic lovers. This unexpected finding promoted my interest in the neurobiology of human emotions and feelings, and significantly shifted my research focus from diseases to physiological states that underlie "love." During this time increasing experimental data broadened the spectrum of activities of oxytocin from female functions, such as parturition and lactation, to modulation of the stress and immune system. The literature also began to reveal an important role for oxytocin in a sense of safety and wellbeing, processes that are critical to both love and survival. I suggest here that future studies should disentangle different emerging questions regarding the exact role of oxytocin within human nature, as well as its possible therapeutic applications in different physiological conditions and pathological states. Understanding these, in turn, holds the potential to improve the lives of both individuals and societies.

Maternal outcomes related to Genetic and epigenetic Variation in the oxytocin system: A scoping review

Purpose

In this scoping review, we synthesize the literature on oxytocin and oxytocin receptor genetic and epigenetic variation in relationship to breastfeeding, maternal caregiving behavior, and maternal mental health.

Methods

A literature search was conducted in early 2022, and updated in 2023, utilizing the PRISMA scoping review reporting method, using the following MeSH headings and key terms: oxytocin, oxytocin receptor, genetics, epigenetics, methylation, pregnancy, postnatal, breastfeeding, lactation, mother-infant relations and perinatal outcomes. The search was conducted using PubMed, EMBASE, CINAHL, Google Scholar, SCOPUS, and the Cochrane Library. Inclusion criteria included: human literature which was peer reviewed and found in primary sources, printed in the English language. In addition, the study must have reported genetic/epigenetic data in either the oxytocin or oxytocin receptor gene (maternal or infant up to 12 months after birth) in relation to a breastfeeding, maternal caregiving behavior or a maternal mental health outcome. There was no date limitation. Four authors reviewed studies for eligibility. Data was extracted using a structured data extraction form.

Results

A total of 23 studies met inclusion criteria for this review (breastfeeding n = 4, maternal caregiving behavior n = 7, and maternal mental health n = 16). Seventeen papers reported on oxytocin or oxytocin receptor genotype and nine reported epigenetic associations (namely DNA methylation). These totals are greater than 23, as studies reported on multiple outcomes. One paper assessed the interaction between genotype and methylation. While a number of genotype variations were reported, the single nucleotide polymorphism rs53576 on the oxytocin receptor gene was the most studied. Overall, variation in this polymorphism was related to postnatal depression symptoms. Among numerous epigenetic markers, site -934 was the most studied methylation site, and methylation status was associated with maternal depression and maternal caregiving behavior outcomes. Results suggest that early life experiences impact adult maternal caregiving behaviors and mental health outcomes, and vary based on genetic vulnerability. Breastfeeding outcomes were minimally studied.

Conclusion

This scoping review found that genetic and epigenetic variation at the oxytocin and oxytocin receptor genes were associated with maternal caregiving behavior and mental health, likely through complex gene and environment interactions. The findings suggest that maternal early life experiences and stress impact later caregiving behaviors and mental health in the postnatal period. The findings highlight potential pathways by which environment, experiences, and genes interact to impact maternal caregiving behavior and maternal mental health.

Oxytocin: A developmental journey

The neuropeptide hormone oxytocin is involved in many processes in our bodies, linking our social lives to our internal states. I started out my career studying primate families, an interest that expanded into the role of oxytocin in family-oriented behaviors such as pair bonding and parenting in prairie voles, humans, and other primates. Starting as a post-doc with Dr. C. Sue Carter, I also became interested in the role of oxytocin during development and the way that we manipulate oxytocin clinically. During that post-doc and then as a faculty member at the University of California, Davis, I have worked on a number of these questions.

Understanding social attachment as a window into the neural basis of prosocial behavior

The representation and demonstration of human values are intimately tied to our status as a social species. Humans are relatively unique in our ability to form enduring social attachments, characterized by the development of a selective bond that persists over time. Such relationships include the bonds between parents and offspring, pair bonds between partners and other affiliative contacts, in addition to group relationships to which we may form direct and symbolic affiliations. Many of the cognitive and behavioral processes thought to be linked to our capacity for social attachment-including consolation, empathy, and social motivation, and the implicated neural circuits mediating these constructs, are shared with those thought to be important for the representation of prosocial values. This perspective piece will examine the hypothesis that our ability to form such long-term bonds may play an essential role in the construction of human values and ethical systems, and that components of prosocial behaviors are shared across species. Humans are one of a few species that form such long-term and exclusive attachments and our understanding of the neurobiology underlying attachment behavior has been advanced by studying behavior in non-human animals. The overlap in behavioral and affective constructs underlying attachment behavior and value representation is discussed, followed by evidence from other species that demonstrate attachment behavior that supports the overlapping neurobiological basis for social bonds and prosocial behavior. The understanding of attachment biology has broad implications for human health as well as for understanding the basis for and variations in prosocial behavior.

Microbes, oxytocin and stress: Converging players regulating eating behavior

Oxytocin is a peptide-hormone extensively studied for its multifaceted biological functions and has recently gained attention for its role in eating behavior, through its action as an anorexigenic neuropeptide. Moreover, the gut microbiota is involved in oxytocinergic signaling through the brain-gut axis, specifically in the regulation of social behavior. The gut microbiota is also implicated in appetite regulation and is postulated to play a role in central regulation of hedonic eating. In this review, we provide an overview on oxytocin and its individual links with the microbiome, the homeostatic and non-homeostatic regulation of eating behavior as well as social behavior and stress.

Genetic polymorphisms in the serotonin, dopamine and opioid pathways influence social attention in rhesus macaques (Macaca mulatta)

Behaviour has a significant heritable component; however, unpicking the variants of interest in the neural circuits and molecular pathways that underpin these has proven difficult. Here, we present a comprehensive analysis of the relationship between known and new candidate genes from identified pathways and key behaviours for survival in 109 adult rhesus macaques (Macaca mulatta). Eight genes involved in emotion were analysed for variation at a total of nine loci. Genetic data were then correlated with cognitive and observational measures of behaviour associated with wellbeing and survival using MCMC-based Bayesian GLMM in R, to account for relatedness within the macaque population. For four loci the variants genotyped were length polymorphisms (SLC6A4 5-hydroxytryptamine transporter length-polymorphic repeat (5-HTTLPR), SLC6A4 STin polymorphism, Tryptophan 5-hydroxylase 2 (TPH2) and Monoamine oxidase A (MAOA)) whilst for the other five (5-hydroxytryptamine receptor 2A (HTR2A), Dopamine Receptor D4 (DRD4), Oxytocin receptor (OXTR), Arginine vasopressin receptor 1A (AVPR1a), Opioid receptor mu(μ) 1 (OPRM1)) SNPs were analysed. STin genotype, DRD4 haplotype and OXTR haplotype were significantly associated with the cognitive and observational measures of behaviour associated with wellbeing and survival. Genotype for 5-HTTLPR, STin and AVPR1a, and haplotype for HTR2A, DRD4 and OXTR were significantly associated with the duration of behaviours including fear and anxiety. Understanding the biological underpinnings of individual variation in negative emotion (e.g., fear and anxiety), together with their impact on social behaviour (e.g., social attention including vigilance for threat) has application for managing primate populations in the wild and captivity, as well as potential translational application for understanding of the genetic basis of emotions in humans.

Simultaneous clustering and variable selection: A novel algorithm and model selection procedure

The growing availability of high-dimensional data sets offers behavioral scientists an unprecedented opportunity to integrate the information hidden in the novel types of data (e.g., genetic data, social media data, and GPS tracks, etc.,) and thereby obtain a more detailed and comprehensive view towards their research questions. In the context of clustering, analyzing the large volume of variables could potentially result in an accurate estimation or a novel discovery of underlying subgroups. However, a unique challenge is that the high-dimensional data sets likely involve a significant amount of irrelevant variables. These irrelevant variables do not contribute to the separation of clusters and they may mask cluster partitions. The current paper addresses this challenge by introducing a new clustering algorithm, called Cardinality K-means or CKM, and by proposing a novel model selection strategy. CKM is able to perform simultaneous clustering and variable selection with high stability. In two simulation studies and an empirical demonstration with genetic data, CKM consistently outperformed competing methods in terms of recovering cluster partitions and identifying signaling variables. Meanwhile, our novel model selection strategy determines the number of clusters based on a subset of variables that are most likely to be signaling variables. Through a simulation study, this strategy was found to result in a more accurate estimation of the number of clusters compared to the conventional strategy that utilizes the full set of variables. Our proposed CKM algorithm, together with the novel model selection strategy, has been implemented in a freely accessible R package.

The DNA methylation landscape of the human oxytocin receptor gene (OXTR): data-driven clusters and their relation to gene expression and childhood adversity

The oxytocin receptor gene (OXTR) is of interest when investigating the effects of early adversity on DNA methylation. However, there is heterogeneity regarding the selection of the most promising CpG sites to target for analyses. The goal of this study was to determine functionally relevant clusters of CpG sites within the OXTR CpG island in 113 mother-infant dyads, with 58 of the mothers reporting childhood maltreatment (CM). OXTR DNA methylation was analyzed in peripheral/umbilical blood mononuclear cells. Different complexity reduction approaches were used to reduce the 188 CpG sites into clusters of co-methylated sites. Furthermore, associations between OXTR DNA methylation (cluster- and site-specific level) and OXTR gene expression and CM were investigated in mothers. Results showed that, first, CpG sections differed strongly regarding their statistical utility for research of individual differences in DNA methylation. Second, cluster analyses and Partial Least Squares (PLS) suggested two clusters consisting of intron1/exon2 and the protein-coding region of exon3, respectively, as most strongly associated with outcome measures. Third, cross-validated PLS regression explained 7% of variance in CM, with low cross-validated variance explained for the prediction of gene expression. Fourth, substantial mother-child correspondence was observed in correlation patterns within the identified clusters, but only modest correspondence outside these clusters. This study makes an important contribution to the mapping of the DNA methylation landscape of the OXTR CpG island by highlighting clusters of CpG sites that show desirable statistical properties and predictive value. We provide a Companion Web Application to facilitate the choice of CpG sites.

Major depressive disorder: biomarkers and biosensors

Depressive disorders belong to highly heterogeneous psychiatric diseases. Loss of in interest in previously enjoyed activities and a depressed mood are the main characteristics of major depressive disorder (MDD). Moreover, due to significant heterogeneity in clinical presentation and lack of applicable biomarkers, diagnosis and treatment remains challenging. Identification of relevant biomarkers would allow for improved disease classification and more personalized treatment strategies. Herein, we review the current state of these biomarkers and then discuss diagnostic techniques of aimed to specifically target these analytes using state of the art biosensor technology.

Epigenetic modifications and obsessive-compulsive disorder: what do we know?

Obsessive-Compulsive Disorder (OCD) is a chronic, severe disabling neuropsychiatric disorder whose pathophysiology is not yet well defined. Generally, the symptom onset occurs during pre-adult life and affects subjects in different life aspects, including professional and social relationships. Although robust evidence indicates the presence of genetic factors in the etiopathology of OCD, the entirely mechanisms are not totally clarified. Thus, the possible interactions between genes and environmental risk factors mediated by epigenetic mechanisms should be sought. Therefore, we provide a review of genetic and epigenetic mechanisms related to OCD with a deep focus on the regulation of critical genes of the central nervous system seeking possible potential biomarkers.

The neurobiology of hatred: Tools of Dialogue© intervention for youth reared amidst intractable conflict impacts brain, behaviour, and peacebuilding attitudes

Myths, drama, and sacred texts have warned against the fragile nature of human love; the closer the affiliative bond, the quicker it can turn into hatred, suggesting similarities in the neurobiological underpinnings of love and hatred. Here, I offer a theoretical account on the neurobiology of hatred based on our model on the biology of human attachments and its three foundations; the oxytocin system, the "affiliative brain", comprising the neural network sustaining attachment, and biobehavioural synchrony, the process by which humans create a coupled biology through coordinated action. These systems mature in mammals in the context of the mother-infant bond and then transfer to support life within social groups. During this transition, they partition to support affiliation and solidarity to one's group and fear and hatred towards out-group based on minor variations in social behaviour. I present the Tools of Dialogue© intervention for outgroup members based on social synchrony. Applied to Israeli and Palestinian youth and implementing RCT, we measured social behaviour, attitudes, hormones, and social brain response before and after the 8-session intervention. Youth receiving the intervention increased reciprocity and reduced hostile behaviour towards outgroup, attenuated the neural marker of prejudice and increased neural empathic response, reduced cortisol and elevated oxytocin, and adapted attitudes of compromise. These neural changes predicted peacebuilding support 7 years later, when young adults can engage in civil responsibilities. Our intervention, the first to show long-term effects of inter-group intervention on brain and behaviour, demonstrates how social synchrony can tilt the neurobiology of hatred towards the pole of affiliation.

Genetic Variation, Stress, and Physiological Stress Response in Adults With Food Allergy or Celiac Disease

BACKGROUND

Persistently high chronic stress can lead to maladaptive psychological, behavioral, and physiological stress responses and poor mental and physical health, highlighting the importance of identifying individuals at increased risk. Chronic health condition diagnosis and genetics are 2 characteristics that can influence stress, stress response, and health outcomes.

PURPOSE

Food allergy (FA) and celiac disease (CD) require constant vigilance in daily life and can lead to increased stress. The purpose of this exploratory analysis was to examine the association of variants in selected stress-related genes with stress exposures, stress, clinical measures of physiological stress response, and mental health symptoms in adults with and without FA or CD.

METHODS

We compared stress exposures, symptoms of PTSD, depression, anxiety, and stress, BMI, and waist-hip ratio between cases and controls. We analyzed the association of SNPs in genes with known or hypothesized associations with stress-related measures in 124 cases and 124 matched controls: CRHBP (rs7718461, rs10474485), CRHR1 (rs242940) and OXTR (rs2268490). For this exploratory study, p-values ≤ 0.10 were considered suggestive.

RESULTS

For cases and controls, rs7718461 was associated with stress symptoms, rs2268490 with symptoms of stress and PTSD, and rs242940 with symptoms of stress, PTSD, anxiety, and depression. Further analyses found that stress-related outcomes in individuals with FA or CD may be influenced by SNP genotype.

CONCLUSIONS

Given these suggestive findings, larger prospective studies should examine similar relationships in individuals with other chronic health conditions, incorporating factors such as environmental exposures, individual experiences, and epigenetic modifications.

Oxytocin receptor is not required for social attachment in prairie voles

Prairie voles are among a small group of mammals that display long-term social attachment between mating partners. Many pharmacological studies show that signaling via the oxytocin receptor (Oxtr) is critical for the display of social monogamy in these animals. We used CRISPR mutagenesis to generate three different Oxtr-null mutant prairie vole lines. Oxtr mutants displayed social attachment such that males and females showed a behavioral preference for their mating partners over a stranger of the opposite sex, even when assayed using different experimental setups. Mothers lacking Oxtr delivered viable pups, and parents displayed care for their young and raised them to the weanling stage. Together, our studies unexpectedly reveal that social attachment, parturition, and parental behavior can occur in the absence of Oxtr signaling in prairie voles.

Genetic and epigenetic effects on couple adjustment in context of romantic relationship: A scoping systematic review

Introduction: Couples' relationships defined by a complex interaction between the two partners and their intrapersonal traits. Romantic; relationships and love are associated with marital satisfaction and stability, as well as couples' happiness and health. Personality traits influence romantic relationships and, personality influenced by genetical and non-genetically factors. The roles of non-genetically factors such as socioeconomic position and external appearance have revealed in determining the quality of romantic relationships. Methods: We; performed a scoping systematic review to assess the association between genetics and epigenetic factors and romantic relationship. Relevant articles were identified by PubMed, EMBASE, Web of Science, Scopus, and the APA PsycInfo searching between inception and 4 June 2022. Results: Different studies evaluated the associated polymorphisms in 15 different genes or chromosomal regions. In the first step; we classified them into four groups: (1) Oxytocin-related signaling pathway (OXTR, CD38, and AVPR1A); (2) Serotonin-related signaling pathway (SLC6A4, HTR1A, and HTR2A); (3) Dopamine and catecholamine-related signaling pathway (DRD1, DRD2, DRD4, ANKK1, and COMT); and (4) other genes (HLA, GABRA2, OPRM1, and Y-DNA haplogroup D-M55). Then, we evaluated and extracted significant polymorphisms that affect couple adjustment and romantic relationships. Discussion: Overall, the findings suggest that genetic and epigenetics variants play a key role in marital adjustment and romantic relationships over time.

The social origins of obesity within and across generations

We propose a model for obesity development that traces a considerable part of its origins to the social domain (mainly different forms of prolonged social adversity), both within and across generations, working in tandem with a genetic predisposition. To facilitate overview of social pathways, we place particular focus on three areas that form a cascading sequence: (A) social adversity within the family (parents having a low education, a low social position, poverty and financial insecurity; offspring being exposed to gestational stress, unmet social and emotional needs, abuse, maltreatment and other negative life events, social deprivation and relationship discord); (B) increasing levels of insecurity, negative emotions, chronic stress, and a disruption of energy homeostasis; and (C) weight gain and obesity, eliciting further social stress and weight stigma in both generations. Social adversity, when combined with genetic predisposition, thereby substantially contributes to highly effective transmission of obesity from parents to offspring, as well as to obesity development within current generations. Prevention efforts may benefit from mitigating multiple types of social adversity in individuals, families, and communities, notably poverty and financial strain, and by improving education levels.

Correlations between single nucleotide polymorphisms in obsessive-compulsive disorder with the clinical features or response to therapy

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder, in which the patient endures intrusive thoughts or is compelled to perform repetitive or ritualized actions. Many cases of OCD are considered to be familial or heritable in nature. It has been shown that a variety of internal and external risk factors are involved in the pathogenesis of OCD. Among the internal factors, genetic modifications play a critical role in the pathophysiological process. Despite many investigations performed to determine the candidate genes, the precise genetic factors involved in the disease remain largely undetermined. The present review summarizes the single nucleotide polymorphisms that have been proposed to be associated with OCD symptoms, early onset disease, neuroimaging results, and response to therapy. This information could help us to draw connections between genetics and OCD symptoms, better characterize OCD in individual patients, understand OCD prognosis, and design more targeted personalized treatment approaches.

Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth.

METHODS

A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2^nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling.

RESULTS

The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL).

CONCLUSIONS

We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

Do the diverse phenotypes of Prader-Willi syndrome reflect extremes of covariation in typical populations?

The phenotypes of human imprinted neurogenetic disorders can be hypothesized as extreme alterations of typical human phenotypes. The imprinted neurogenetic disorder Prader-Willi syndrome (PWS) features covarying phenotypes that centrally involve altered social behaviors, attachment, mood, circadian rhythms, and eating habits, that can be traced to altered functioning of the hypothalamus. Here, we conducted analyses to investigate the extent to which the behavioral variation shown in typical human populations for a set of PWAS-associated traits including autism spectrum cognition, schizotypal cognition, mood, eating, and sleeping phenotypes shows covariability that recapitulates the covariation observed in individuals with PWS. To this end, we collected data from 296 typical individuals for this set of phenotypes, and showed, using principal components analysis, evidence of a major axis reflecting key covarying PWS traits. We also reviewed the literature regarding neurogenetic syndromes that overlap in their affected traits with PWS, to determine their prevalence and properties. These findings demonstrate that a notable suite of syndromes shows phenotypic overlap with PWS, implicating a large set of imprinted and non-imprinted genes, some of which interact, in the phenotypes of this disorder. Considered together, these findings link variation in and among neurogenetic disorders with variation in typical populations, especially with regard to pleiotropic effects mediated by the hypothalamus. This work also implicates effects of imprinted gene variation on cognition and behavior in typical human populations.

Microarray profiling of hypothalamic gene expression changes in Huntington’s disease mouse models

Structural changes and neuropathology in the hypothalamus have been suggested to contribute to the non-motor manifestations of Huntington’s disease (HD), a neurodegenerative disorder caused by an expanded cytosine-adenine-guanine (CAG) repeat in the huntingtin (HTT) gene. In this study, we investigated whether hypothalamic HTT expression causes transcriptional changes. Hypothalamic RNA was isolated from two different HD mouse models and their littermate controls; BACHD mice with ubiquitous expression of full-length mutant HTT (mHTT) and wild-type mice with targeted hypothalamic overexpression of either wild-type HTT (wtHTT) or mHTT fragments. The mHTT and wtHTT groups showed the highest number of differentially expressed genes compared to the BACHD mouse model. Gene Set Enrichment Analysis (GSEA) with leading-edge analysis showed that suppressed sterol- and cholesterol metabolism were shared between hypothalamic wtHTT and mHTT overexpression. Most distinctive for mHTT overexpression was the suppression of neuroendocrine networks, in which qRT-PCR validation confirmed significant downregulation of neuropeptides with roles in feeding behavior; hypocretin neuropeptide precursor (Hcrt), tachykinin receptor 3 (Tacr3), cocaine and amphetamine-regulated transcript (Cart) and catecholamine-related biological processes; dopa decarboxylase (Ddc), histidine decarboxylase (Hdc), tyrosine hydroxylase (Th), and vasoactive intestinal peptide (Vip). In BACHD mice, few hypothalamic genes were differentially expressed compared to age-matched WT controls. However, GSEA indicated an enrichment of inflammatory- and gonadotropin-related processes at 10 months. In conclusion, we show that both wtHTT and mHTT overexpression change hypothalamic transcriptome profile, specifically mHTT, altering neuroendocrine circuits. In contrast, the ubiquitous expression of full-length mHTT in the BACHD hypothalamus moderately affects the transcriptomic profile.

Associations of air PM2.5 level with gut microbiota in Chinese Han preschoolers and effect modification by oxytocin receptor gene polymorphism

Variations in the single nucleotide polymorphisms (SNPs) of the oxytocin receptors (OXTR) indicate individual differences in stress response, social behavior, and psychopathology, but very few paper mentioned OXTR as part of the mechanism linking exposure to air pollution and poor social interactions. The authors investigated the moderating role of Oxytocin receptor (OXTR) rs53576 polymorphism in the relationship between PM_2.5 level and gut microbiota in children, in an attempt to provide some reference for the evidence linking biological and environmental factors to children brain development. The study included 86 healthy Chinese preschoolers (50 males, 36 females) from two campuses of a kindergarten with different air PM_2.5 levels. Atmospheric PM_2.5 values released by air quality monitoring stations where the two campuses are located were collected for 30 days. The genotypes of OXTR rs53576 were determined by PCR and restriction fragment length polymorphism. The gut microbiota situation was evaluated by determining urinary concentrations of short-chain fatty acids. Urinary levels of cortisone and cortisol were determined to assess the impact of air pollution on the HPA axis. Urinary 2'-Deoxy-7,8-dihydro-8-oxoguanosine and 8-oxo-7,8-dihydroguanosine were measured to evaluate the oxidative stress state. The genotype distribution frequency of rs53576 polymorphism was consistent with Hardy-Weinberg equilibrium. The average urinary concentrations of cortisone, cortisol and 8-OHdG in high pollution campus preschoolers were significantly higher than those in low pollution campus preschoolers, while situations were opposite for acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid. The interaction between OXTR rs53576 and air pollution had a significant effect on urinary acetic acid. Allele G of rs53576 may be a risk factor for gut microbiota disorder caused by air pollution, and children with GA/GG genotype may be more susceptible than those with AA genotype.

Enhanced endogenous oxytocin signaling in the brain modulates neural responses to social misalignment and promotes conformity in humans: A multi-locus genetic profile approach

The neuropeptide oxytocin (OT) is known to promote social conformity. However, the specific neurocognitive mechanisms underlying OT-induced conformity remain unclear. We aimed to address this gap by examining how genetic variation in the oxytocin receptor gene (OXTR) is linked with behavioral conformity and its underlying neural systems. Specifically, we utilized the genotype-tissue expression database (GTEx) to create a novel multi-locus genetic profile score (MPS) that reflects the level of OXTR expression in the human brain. A total of 194 participants (Neuroimaging N = 50, Behavioral N = 144) performed a novel conformity task in which they viewed a series of word pairs depicting various moral values and virtues widely recognized in the United States. In each trial, participants indicated the relative importance of these words and subsequently learned about the majority opinion. Participants later rated the same word pairs a second time. Changes in participants' ratings between the first and second sessions were measured and analyzed with respect to social feedback, blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals, and OXTR MPS. We found that participants adjusted their ratings in accordance with the majority opinions. Social misalignment between self and others activated brain areas such as the striatum and the posterior medial frontal cortex (pMFC). However, unlike most findings from previous studies, activation in the pMFC during the inconsistent social feedback negatively, rather than positively, predicted behavioral conformity. Notably, those with higher OXTR MPS had reduced pMFC activation in the face of social misalignment, which led to greater conformity. Our findings suggest that OT may promote conformity by dampening the conflict-related signals in the pMFC. They also show that OXTR MPS may be useful for studying the effect of genes on highly complex human social traits, such as conformity.

Models of gene-culture evolution are incomplete without incorporating epigenetic effects

Epigenetics impacts gene-culture coevolution by amplifying phenotypic variation, including clustering, and bridging the difference in timescales between genetic and cultural evolution. The dual inheritance model described by Uchiyama et al. could be modified to provide greater explanatory power by incorporating epigenetic effects.

The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth

Developmental neuroscience research has not yet fully unveiled the dynamics involved in human birth. The trigger of the first breath, often assumed to be the marker of human life, has not been characterized nor has the process entailing brain modification and activation at birth been clarified yet. To date, few researchers only have investigated the impact of the extrauterine environment, with its strong stimuli, on birth. This ‘hypothesis and theory' article assumes the role of a specific stimulus activating the central nervous system (CNS) at human birth. This stimulus must have specific features though, such as novelty, efficacy, ubiquity, and immediacy. We propose light as a robust candidate for the CNS activation via the retina. Available data on fetal and neonatal neurodevelopment, in particular with reference to retinal light-responsive pathways, will be examined together with the GABA functional switch, and the subplate disappearance, which, at an experimental level, differentiate the neonatal brain from the fetal brain. In this study, we assume how a very rapid activation of retinal photoreceptors at birth initiates a sudden brain shift from the prenatal pattern of functions to the neonatal setup. Our assumption implies the presence of a photoreceptor capable of capturing and transducing light/photon stimulus, transforming it into an effective signal for the activation of new brain functions at birth. Opsin photoreception or, more specifically, melanopsin-dependent photoreception, which is provided by intrinsically photosensitive retinal ganglion cells (ipRGCs), is considered as a valid candidate. Although what is assumed herein cannot be verified in humans based on knowledge available so far, proposing an important and novel function can trigger a broad range of diversified research in different domains, from neurophysiology to neurology and psychiatry.

Oxytocin—a social peptide? Deconstructing the evidence

In this paper, we analyse the claim that oxytocin is a ‘social neuropeptide’. This claim originated from evidence that oxytocin was instrumental in the initiation of maternal behaviour and it was extended to become the claim that oxytocin has a key role in promoting social interactions between individuals. We begin by considering the structure of the scientific literature on this topic, identifying closely interconnected clusters of papers on particular themes. We then analyse this claim by considering evidence of four types as generated by these clusters: (i) mechanistic studies in animal models, designed to understand the pathways involved in the behavioural effects of centrally administered oxytocin; (ii) evidence from observational studies indicating an association between oxytocin signalling pathways and social behaviour; (iii) evidence from intervention studies, mainly involving intranasal oxytocin administration; and (iv) evidence from translational studies of patients with disorders of social behaviour. We then critically analyse the most highly cited papers in each segment of the evidence; we conclude that, if these represent the best evidence, then the evidence for the claim is weak.

This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.

Revealing the Increased Stress Response Behavior through Transcriptomic Analysis of Adult Zebrafish Brain after Chronic Low to Moderate Dose Rates of Ionizing Radiation

Simple Summary

The increasing use of radiopharmaceuticals for medical diagnostics and radiotherapy raises concerns regarding health risks for both humans and the environment. Additionally, in the context of major nuclear accidents like in Chernobyl and Fukushima, very little is known about the effects of chronic exposure to low and moderate dose rates of ionizing radiation (IR). Many studies demonstrated the sensibility of the developmental brain, but little data exists for IR at low dose rates and their impact on adults. In this study, we characterized the molecular mechanisms that orchestrate stress behavior caused by chronic exposure to low to moderate dose rates of IR using the adult zebrafish model. We observed the establishment of a congruent stress response at both the molecular and individual levels.

Abstract

High levels of ionizing radiation (IR) are known to induce neurogenesis defects with harmful consequences on brain morphogenesis and cognitive functions, but the effects of chronic low to moderate dose rates of IR remain largely unknown. In this study, we aim at defining the main molecular pathways impacted by IR and how these effects can translate to higher organizational levels such as behavior. Adult zebrafish were exposed to gamma radiation for 36 days at 0.05 mGy/h, 0.5 mGy/h and 5 mGy/h. RNA sequencing was performed on the telencephalon and completed by RNA in situ hybridization that confirmed the upregulation of oxytocin and cone rod homeobox in the parvocellular preoptic nucleus. A dose rate-dependent increase in differentially expressed genes (DEG) was observed with 27 DEG at 0.05 mGy/h, 200 DEG at 0.5 mGy/h and 530 DEG at 5 mGy/h. Genes involved in neurotransmission, neurohormones and hypothalamic-pituitary-interrenal axis functions were specifically affected, strongly suggesting their involvement in the stress response behavior observed after exposure to dose rates superior or equal to 0.5 mGy/h. At the individual scale, hypolocomotion, increased freezing and social stress were detected. Together, these data highlight the intricate interaction between neurohormones (and particularly oxytocin), neurotransmission and neurogenesis in response to chronic exposure to IR and the establishment of anxiety-like behavior.

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.

The role of maternal exercise on placental, behavioral and genetic alterations induced by prenatal stress

The present study aimed to evaluate the effects of treadmill maternal exercise on alterations induced by prenatal stress in neonatal mice. Female and male Balb/c mice were divided into five groups: control (CON), prenatal restraint stress (PNS), prenatal restraint stress and physical exercise before pregnancy (PNS + EX1), prenatal restraint stress and physical exercise during pregnancy (PNS + EX2), and prenatal restraint stress and physical exercise before and during pregnancy (PNS + EX3). Exercise was performed using a treadmill, at a speed of 10 m/min, for 60 minutes, 5 days a week. Maternal behavior was assessed on days 3, 4 and 5 postpartum (PPD). Placental gene expression of glucocorticoid receptor (GR), 11-β-hydroxysteroid dehydrogenase 2 (11β-HSD2), 5-hydroxytryptamine receptor 1A (5HT_1AR), and corticotropin releasing hormone receptor 1 (CRHR1) were analyzed. In neonatal mice, the gene expression of GR, mineralocorticoid receptor (MR), CRHR1, 5HTr1, oxytocin Receptor 1 (OXTr1), tropomyosin related kinase B (TRκB), brain-derived neurotrophic factor exon I (BDNF I), and BDNF IV was analyzed in the brain (PND0) and hippocampus (PND10). Maternal exercise improved (p < 0.05) maternal care. In the placenta, maternal exercise prevented (p < 0.01) the increase in GR expression caused by PNS. In the brain from PND0, exercise before pregnancy prevented (p = 0.002) the decreased CRHR1 expression promoted by PNS. In the hippocampus of PND10 males, PNS decreased (p = 0.0005) GR expression, and exercise before pregnancy prevented (p = 0.003) this effect. In PND10 females, maternal exercise prevented (p < 0.05) the PNS-induced increase in MR expression. PNS + EX2 males showed increased (p < 0.01) BDNF I gene expression and PNS + EX1 females demonstrated increased (p = 0.03) BDNF IV expression. In conclusion, maternal physical exercise may play a role in modulating maternal-fetal health and may contribute to preventing neurodevelopmental changes induced by prenatal stress.

The Interaction Effect of Parental Rejection and Oxytocin Receptor Gene Polymorphism on Depression: A Cross-Cultural Study in Non-Clinical Samples

Parental rejection has been consistently empirically implicated in a wide array of developmental, behavioural and psychological problems worldwide. However, the interaction effect between parental rejection in childhood and the oxytocin receptor genotype on psychological adjustment has yet to be investigated. The present study aimed to investigate gene–environment interaction effects between parental rejection (maternal and paternal) and oxytocin receptor (OXTR) gene polymorphisms (rs53576 and rs2254298) on depressive symptoms in adults in different cultural contexts. Adults from Italy and Japan (N = 133, age = 18–27 years, females = 68) were preliminarily genotyped and then completed the Parental Acceptance-Rejection Questionnaire for mothers and fathers and the Beck Depression Inventory. Hierarchical multiple regression analysis showed that paternal rejection was related to self-reported depression and that the effect of parental rejection was moderated by OXTR gene polymorphisms and nationality. Among Italians, OXTR rs2254298 A-carriers showed resilience to negative early parental care, whereas among Japanese, OXTR rs53576 non-A-carriers showed resistance to negative early paternal care. These findings align with expected relations between perceived acceptance–rejection and an individual’s psychological adjustment, as proposed by interpersonal acceptance–rejection theory, and indicate the need for future studies adopting a multicultural and multilevel approach to better understand how the effects of parental rejection extend into adulthood.

Predicting the Treatment Outcomes of Antidepressants Using a Deep Neural Network of Deep Learning in Drug-Naïve Major Depressive Patients

Predicting the treatment response to antidepressants by pretreatment features would be useful, as up to 70–90% of patients with major depressive disorder (MDD) do not respond to treatment as expected. Therefore, we aim to establish a deep neural network (DNN) model of deep learning to predict the treatment outcomes of antidepressants in drug-naïve and first-diagnosis MDD patients during severe depressive stage using different domains of signature profiles of clinical features, peripheral biochemistry, psychosocial factors, and genetic polymorphisms. The multilayer feedforward neural network containing two hidden layers was applied to build models with tenfold cross-validation. The areas under the curve (AUC) of the receiver operating characteristic curves were used to evaluate the performance of the models. The results demonstrated that the AUCs of the model ranged between 0.7 and 0.8 using a combination of different domains of categorical variables. Moreover, models using the extracted variables demonstrated better performance, and the best performing model was characterized by an AUC of 0.825, using the levels of cortisol and oxytocin, scales of social support and quality of life, and polymorphisms of the OXTR gene. A complex interactions model developed through DNN could be useful at the clinical level for predicting the individualized outcomes of antidepressants.

Oxytocin receptor genotype moderates the association between maternal prenatal stress and infant early self-regulation

INTRODUCTION

Maternal prenatal stress may have long-term adverse consequences for child development. Accumulating evidence shows that the oxytocin-receptor genotype may play a role in differential susceptibility to early-life adversity, but no studies have examined whether this moderation extends to the prenatal stress exposures.

METHODS

In the FinnBrain Birth Cohort Study, a sample of 1173 mother-child dyads were examined. We studied the possible moderating effect of the cumulative effect of infant oxytocin-receptor risk genotypes (rs53576GG and rs2254298A) in the association between maternal prenatal stress, and infant negative reactivity and emerging self-regulation at 6 months of age.

RESULTS

The number of OTr risk genotypes moderated the association between maternal prenatal anxiety and infant self-regulation, implying a cumulative effect of genotype, although effects sizes were small. In infants with two risk genotypes, a negative association between prenatal anxiety and self-regulation was observed, whereas in infants with one or no risk genotypes, the association between maternal prenatal anxiety and temperament was non-significant.

CONCLUSION

Oxytocin-receptor genotype may moderate the association of maternal stress during pregnancy and child social-emotional development. Possible mechanisms for this moderation effect are discussed. Further studies with a more comprehensive polygenic approach are needed to confirm these results.

Emotion regulation moderates between maternal adverse childhood experiences (ACEs) and oxytocin response

Exposure to adverse childhood experiences (ACEs) is associated with oxytocin dysregulation in women, such as decreased peripheral oxytocin concentrations, but little is known about vulnerability markers for oxytocin dysregulation in mothers exposed to ACEs. Identifying vulnerability markers may help inform future targets for prevention and intervention programmes. This study provided a preliminary examination of emotion regulation as a potential moderator of the association between maternal ACEs and peripheral oxytocin levels. The current study included a sample of 38 postpartum women. Women completed questionnaires on exposure to ACEs and difficulties with emotion regulation. At a clinic visit at 9 months postpartum, women provided plasma and salivary oxytocin samples anchored around a mother-infant interaction. Associations between maternal ACEs, three dimensions of difficulties with emotion regulation, and peripheral oxytocin concentrations were examined. Linear regression analyses showed that greater difficulties engaging in goal-directed behaviour (β =  - 0.50, p = 0.01) and more limited access to effective emotion regulation strategies (β =  - 0.68, p < 0.001) were related to reduced plasma oxytocin concentrations in postpartum women. Furthermore, in postpartum women reporting greater exposure to ACEs, higher levels of nonacceptance of emotional responses (β =  - 0.55, p = 0.01) and more limited access to effective emotion regulation strategies (β =  - 0.54, p = 0.01) were associated with reduced salivary oxytocin response (i.e. decreased change in oxytocin concentrations from baseline) following mother-infant interaction. Difficulties with emotion regulation may serve as a vulnerability marker for oxytocin dysregulation in postpartum women exposed to ACEs, and this suggests that emotion regulation may be an important target for future clinical interventions. Future research is recommended which replicates these preliminary results and which examines how emotion regulation and peripheral oxytocin levels in mothers exposed to ACEs are associated with parenting and child development outcomes.

Birth, love, and fear: Physiological networks from pregnancy to parenthood

Pregnancy and childbirth are among the most dramatic physiological and emotional transformations of a lifetime. Despite their central importance to human survival, many gaps remain in our understanding of the temporal progression of and mechanisms underlying the transition to new parenthood. The goal of this paper is to outline the physiological and emotional development of the maternal-infant dyad from late pregnancy to the postpartum period, and to provide a framework to investigate this development using non-invasive timeseries. We focus on the interaction among neuroendocrine, emotional, and autonomic outputs in the context of late pregnancy, parturition, and post-partum. We then propose that coupled dynamics in these outputs can be leveraged to map both physiologic and pathologic pregnancy, parturition, and parenthood. This approach could address gaps in our knowledge and enable early detection or prediction of problems, with both personalized depth and broad population scale.

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Giving birth and caring for offspring are dynamic processes that can instill both love and fear.

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Maternal physiology continuously integrates fetal, social, and environmental cues.

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The result is coupled change in hormonal, autonomic nervous, and emotional output.

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Coupling may allow internal state to be assessed from peripheral autonomic markers.

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Such markers may identify healthy or pathologic pregnancy, parturition, and parenting, and enable creation of real-world tools.

Oxytocin system gene methylation is associated with empathic responses towards children

Empathy is an essential component of sensitive caregiving behavior, which in turn is an important predictor of children's healthy social-emotional development. The oxytocin (OXT) system plays a key role in promoting sensitive parenting and empathy. In this study, we investigated how OXT system gene methylation was associated with empathic processes in nulliparous women (M age = 23.60, SD =0.44)-measuring both physiological facial muscle responses and ratings of compassion and positive affect to affective images depicting children. Linear mixed effects analyses demonstrated that lower methylation levels in the OXT and OXTR genes were related to enhanced empathic responses. The effect of OXT system gene methylation on empathic processes was partly qualified by an interaction with individual variations in women's care motivation. Our findings provide experimental evidence for an association between the methylation of OXT system genes and empathy.

Towards better hypothesis tests in oxytocin research: Evaluating the validity of auxiliary assumptions

Various factors have been attributed to the inconsistent reproducibility of human oxytocin research in the cognitive and behavioral sciences. These factors include small sample sizes, a lack of pre-registered studies, and the absence of overarching theoretical frameworks that can account for oxytocin's effects over a broad range of contexts. While there have been efforts to remedy these issues, there has been very little systematic scrutiny of the role of auxiliary assumptions, which are claims that are not central for testing a hypothesis but nonetheless critical for testing theories. For instance, the hypothesis that oxytocin increases the salience of social cues is predicated on the assumption that intranasally administered oxytocin increases oxytocin levels in the brain. Without robust auxiliary assumptions, it is unclear whether a hypothesis testing failure is due to an incorrect hypothesis or poorly supported auxiliary assumptions. Consequently, poorly supported auxiliary assumptions can be blamed for hypothesis failure, thereby safeguarding theories from falsification. In this article, I will evaluate the body of evidence for key auxiliary assumptions in human behavioral oxytocin research in terms of theory, experimental design, and statistical inference, and highlight assumptions that require stronger evidence. Strong auxiliary assumptions will leave hypotheses vulnerable for falsification, which will improve hypothesis testing and consequently advance our understanding of oxytocin's role in cognition and behavior.

Neurobiological Correlates of Fatherhood During the Postpartum Period: A Scoping Review

During the postpartum period, the paternal brain suffers extensive and complex neurobiological alterations, through the experience of father-infant interactions. Although the impact of such experience in the mother has been increasingly studied over the past years, less is known about the neurobiological correlates of fatherhood-that is, the alterations in the brain and other physiological systems associated with the experience of fatherhood. With the present study, we aimed to perform a scoping review of the available literature on the genetic, neuroendocrine, and brain correlates of fatherhood and identify the main gaps in the current knowledge. PubMed, Scopus, and Web of Science electronic databases were searched for eligible studies on paternal neuroplasticity during the postpartum period, over the past 15 years. Reference lists of relevant key studies and reviews were also hand-searched. The research team independently screened the identified studies based on the established inclusion criteria. Extracted data were analyzed using tables and descriptive synthesis. Among the 29 studies that met our inclusion criteria, the vast majority pertained to neuroendocrine correlates of fatherhood (n = 19), followed by brain activity or connectivity (n = 7), association studies of candidate genes (n = 2), and brain structure correlates (n = 1). Collectively, studies published during the past 15 years suggest the existence of significant endocrine (testosterone, oxytocin, prolactin, and cortisol levels) and neurofunctional alterations (changed activity in several brain networks related to empathy and approach motivation, emotional processing and mentalizing, emotion regulation, dorsal attention, and default mode networks) as a result of fatherhood, as well as preliminary evidence of genetic variability accounting for individual differences during the postpartum period in fathers. No studies were so far published evaluating epigenetic mechanisms associated with the paternal brain, something that was also the focus of the current review. We highlight the need for further research that examines neuroplasticity during the experience of fatherhood and that considers both the interplay between hormones and simultaneous assessment of the different biomarkers (e.g., associations between hormones and neural activity); data collection protocols and assessment times should also be refined.

Depressive symptomatology, temperament and oxytocin serum levels in a sample of healthy female university students

Background

Depressive symptomatology is prevalent among female university students with adverse effects on their quality of life and academic performance. Previous research suggested associations between depressive symptomatology and oxytocin levels and between depressive symptomatology and Temperament Traits. Despite this evidence, to the best of our knowledge no research has studied the effects fboth oxytocin serum levels and temperament dimensions on depressivesymptoms in a healthy sample. The present study aimed to analyse the effect of oxytocin levels and temperament traits on depressive symptomatology in healthy female university students.

Methods

All participants completed the Beck Depression Inventory and the Adult Temperament Questionnaire. Blood samples were collected between 8 and 8H30 a.m. after 12 h of fasting and between 5 and 8 day of the menstrual cycle and serum oxytocin levels were quantified using a commercial enzyme-linked immunosorbent assay. A hierarchical multiple regression model using a stepwise method was conducted to identify predictors of depression.

Results

Forty-five women aged between 18 and 25 years old (19.37 ± 1.32 years) volunteered to participate in this study. Depressive symptomatology was negatively associated with oxytocin serum levels and "Negative affect" and positively associated with "Effortful control" and "Activation Control". In the final regression model, only oxytocin level was a predictor (B = − 0.090, p < 0.0001), the model explaining 65.2% of the depression variation. Oxytocin played a mediation role between "Negative affects" and Depressive symptomatology.

Conclusions

Our results showed that oxytocin level, rather than personality dimensions, was associated with depressive symptomatology. These results highlight the relevance of the discussion on the use of oxytocin as a biological marker of emotional and social symptoms that characterize depression.

Impact of OXTR Polymorphisms on Subjective Well-Being: The Intermediary Role of Attributional Style

Polymorphisms in the oxytocin receptor (OXTR) gene are related to individual differences in negative emotions, such as depressive symptoms and anxiety. However, it remains unclear what the potential roles of OXTR polymorphisms are in subjective well-being (SWB), which is negatively correlated with depressive symptoms. We examined attributional styles as mediator between SWB and five polymorphisms of the oxytocin receptor gene (OXTR rs53576, rs2254298, rs1042778, rs2268494, and rs2268490) among 627 full-time college freshmen (M_age = 20.90, SD = 0.82 for male; M_age = 20.81, SD = 0.92 for female) using structural equation modeling. The results showed that individuals with the OXTR rs2254298 AA genotype and rs53576 AA/GA genotype reported higher scores on SWB, which suggested that individuals with this genotype experienced more happiness. Moreover, external attributional style partially mediated the association between OXTR rs2254298 polymorphism and SWB (β = 0.019, 95%CI [0.001, 0.036], p = 0.035). In conclusion, our findings demonstrated that the genetic variations of OXTR played a role in the individual differences of SWB, and external attribution style could mediate the association.