Genetic imaging of the association of oxytocin receptor gene (OXTR) polymorphisms with positive maternal parenting

Cumulative Genetic Scores Interact with Maternal and Paternal Parenting in Predicting Parent-Adolescent Cohesion and Conflict

Previous research concerning the interplay between genetics and parenting in the development of the parent-child relationship during adolescence has been extremely scarce, predominantly adopting single-gene designs. This limited body of work has largely overlooked the distinct effects of maternal and paternal roles, as well as potential gender differences. Additionally, existing gene-by-environment (G × E) studies have mainly concentrated on adverse environmental factors and associated negative outcomes, somewhat neglecting positive environments and outcomes. The present study examined the interactions of cumulative genetic scores (CGS, dopamine receptor D2 TaqIA and oxytocin receptor gene rs53576 polymorphisms) with both positive and negative parenting on parent-adolescent cohesion and conflict. Furthermore, this study aimed to ascertain with which gene-environment model the potential G × E interactions would align. A total of 745 Chinese Han adolescents (Mage = 13.36 ± 0.96 years; 46.8% girls) from grades 7 to 9 participated in this study. Results revealed a significant effect of CGS and negative maternal parenting on mother-adolescent conflict among males, consistent with the weak differential susceptibility model. As CGS increased, the effects of negative maternal parenting on mother-son conflict were magnified. These findings have implications for the timing and focus of interventions aimed at improving parent-adolescent relationships.

The extended neural architecture of human attachment: An fMRI coordinate-based meta-analysis of affiliative studies

Functional imaging studies and clinical evidence indicate that cortical areas relevant to social cognition are closely integrated with evolutionarily conserved basal forebrain structures and neighboring regions, enabling human attachment and affiliative emotions. The neural circuitry of human affiliation is continually being unraveled as functional magnetic resonance imaging (fMRI) becomes increasingly prevalent, with studies examining human brain responses to various attachment figures. However, previous fMRI meta-analyses on affiliative stimuli have encountered challenges, such as low statistical power and the absence of robustness measures. To address these issues, we conducted an exhaustive coordinate-based meta-analysis of 79 fMRI studies, focusing on personalized affiliative stimuli, including one's infants, family, romantic partners, and friends. We employed complementary coordinate-based analyses (Activation Likelihood Estimation and Signed Differential Mapping) and conducted a robustness analysis of the results. Findings revealed cluster convergence in cortical and subcortical structures related to reward and motivation, salience detection, social bonding, and cognition. Our study thoroughly explores the neural correlates underpinning affiliative responses, effectively overcoming the limitations noted in previous meta-analyses. It provides an extensive view of the neural substrates associated with affiliative stimuli, illuminating the intricate interaction between cortical and subcortical regions. Our findings significantly contribute to understanding the neurobiology of human affiliation, expanding the known human attachment circuitry beyond the traditional basal forebrain regions observed in other mammals to include uniquely human isocortical structures.

Cortisol Reactivity and Observed Parenting among Mothers of Children with and without ADHD

OBJECTIVE

Neurobiological models suggest links between maternal cortisol reactivity and parenting; however, no studies have examined cortisol reactivity and parenting in mothers of school-age children with ADHD.

METHOD

We examined the relationship between observed parenting and maternal cortisol reactivity in two laboratory contexts: the Trier Social Stress Task (TSST) and parenting-child interaction (PCI). Mothers of children with (N = 24) and without (N = 36) ADHD participated.

RESULTS

During the TSST, greater cortisol output and increase were associated with decreased positive and increased negative parenting. However, during the PCI, cortisol output was associated with increased self-reported and observed positive parenting, and decreased observed negative parenting. Cortisol change during the PCI was associated with decreased observed positive parenting and increased self-reported negative parenting. Among mothers of children with ADHD, cortisol output during the PCI was negatively associated with negative, inconsistent parenting. Change in cortisol predicted more inconsistent discipline and corporal punishment.

CONCLUSION

Findings contribute to an integrative biological, psychological, and cognitive process model of parenting in families of children with ADHD.

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.

Oxytocin Receptor Gene Polymorphism in Lactating Dogs

Simple Summary

Oxytocin is commonly known for its role in mammalian bonding. Several studies have proved that polymorphisms of the oxytocin receptor gene are related to complex social behaviors in humans, but studies on the possible correlation between canine social behavior and oxytocin are mainly focused on the human–dog bond, and there are no data on the possible correlation between oxytocin receptor gene polymorphism and the maternal behavior of this species. Since mother–litter interactions could have a severe impact in determining later behavior in domestic dogs, the aim of this work was to investigate the possible correlation between salivary oxytocin, maternal care and the one known single-nucleotide polymorphism (rs8679684) located in the untranslated regulatory region of the oxytocin receptor gene in 19 lactating Labrador Retriever dogs. A significant correlation between oxytocin receptor gene polymorphism, peripheral oxytocin and maternal behavior in dogs was found. This implies that a more functional oxytocinergic system would lead to better mothering in dogs.

Abstract

Genetic variations in the oxytocinergic system, known to regulate social behavior throughout the evolution of mammals, are believed to account for differences in mammalian social behavior. Particularly, polymorphic variants of the oxytocin receptor (OXTR) gene have been associated with behavioral variations in both humans and dogs. In this study, we offered evidence of the correlation between levels of salivary oxytocin (sOXT), maternal behavior and a single-nucleotide gene variant in OXTR (rs8679684) in nineteen lactating Labrador Retriever dogs. Carriers of at least one copy of the minor A allele showed higher levels of sOXT and maternal care in comparison with the homozygous T allele carriers. Considering the relevance of mother care in newborn development, these findings could help us to better understand the possible impact of variants in the OXTR gene in selecting dams.

Understanding identification-based trust in the light of affiliative bonding: Meta-analytic neuroimaging evidence

Trust is vital for establishing social relationships and is a crucial precursor for affiliative bonds. Investigations explored the neuropsychological bases of trust separately (e.g., measured by the trust game) and affiliative bonding (e.g., measured by parental care, pair-bonding, or friendship). However, direct empirical support for the shared neural mechanisms between trust and affiliative bonding is missing. Here, we conducted a coordinate-based meta-analysis on functional magnetic resonance imaging studies on interpersonal trust and affiliative bonding using the activation likelihood estimation method. Our results demonstrated that decisions to trust strangers in repeated interactions (i.e., identification-based trust) engaged the ventral striatum (vSTR, part of the mesolimbic dopaminergic pathway), likely signaling the reward anticipation. Further, both feedbacks in repeated interactions and affiliative bonding engaged the dorsal striatum (dSTR, part of the nigrostriatal dopaminergic pathway), likely encoding learning dynamics. Our findings suggest that identification-based trust can be understood in the light of affiliative bonding, involving the mesocorticolimbic "reward" pathway (vSTR) and nigrostriatal "habit formation" pathway (dSTR) in building and sustaining social relationships.

Neural signatures of parental empathic responses to imagined suffering of their adolescent child

Empathy is deemed indispensable for sensitive caregiving. Neuroimaging studies have identified canonical empathy networks consisting of regions supporting cognitive and affective aspects of empathy. However, not much is known about how these regions support empathy towards one's own offspring and how this neural activity relates to parental caregiving. We introduce a novel task to assess affective and neural responses to the suffering of one's own adolescent child. While in the scanner, 60 parents (n = 35 mothers, n = 25 fathers) were confronted with unpleasant situations involving their own child, an unfamiliar child, and themselves. Parents were asked to vividly imagine these situations and indicate their levels of distress. Parents reported higher levels of distress when imagining suffering for their own child relative to an unfamiliar child or themselves. Neuroimaging results showed increased activation within the cognitive empathy network (i.e., temporoparietal junction, dorsomedial- and ventromedial prefrontal cortex) when contrasting suffering of one's own child versus an unfamiliar child or the self. The task also engaged regions of the affective empathy network (i.e., anterior insula and anterior mid-cingulate cortex), which was however not modulated by whether suffering was for the self, one's own child, or an unfamiliar child. Parental care did not co-vary with activity in the empathy networks, but parents who were perceived as less caring exhibited increased activity in anterior prefrontal regions when imagining their own child suffering. These results provide new insights into neural processes supporting parental empathy, highlighting the importance of regions in the cognitive empathy network when confronted with the suffering of their own adolescent child, and suggest that additional (i.e., emotion regulation) networks may be relevant for parental caring behavior in daily life.

Affective Neural Mechanisms of a Parenting-Focused Mindfulness Intervention

OBJECTIVES

Behavioral evidence suggests that parenting-focused mindfulness interventions can improve parenting practices and enhance family wellbeing, potentially operating through altered emotional processing in parents. However, the mechanisms through which parent mindfulness interventions achieve their positive benefits have not yet been empirically tested, knowledge which is key to refine and maximize intervention effects. Thus, as part of a randomized controlled trial, the present study examined the affective mechanisms of an 8-week parenting-focused mindfulness intervention, the Parenting Mindfully (PM) intervention, versus a minimal-intervention parent education control.

METHODS

Twenty highly stressed mothers of adolescents completed pre- and post-intervention behavioral and fMRI sessions, in which mothers completed a parent-adolescent conflict interaction, fMRI emotion task, and fMRI resting state scan. Mothers reported on their mindful parenting, and maternal emotional reactivity to the parent-adolescent conflict task was assessed via observed emotion expression, self-reported negative emotion, and salivary cortisol reactivity.

RESULTS

Results indicated that the PM intervention increased brain responsivity in left posterior insula in response to negative affective stimuli, and altered resting state functional connectivity in regions involved in self-reference, behavioral regulation, and social-emotional processing. Changes in mothers' brain function and connectivity were associated with increased mindful parenting and decreased emotional reactivity to the parent-adolescent conflict task.

CONCLUSIONS

Findings suggest that mindfulness-based changes in maternal emotional awareness at the neurobiological level are associated with decreased emotional reactivity in parenting interactions, illuminating potential neurobiological targets for future parent-focused intervention.

The promiscuity of the oxytocin-vasopressin systems and their involvement in autism spectrum disorder

Oxytocin and vasopressin systems have been studied separately in autism spectrum disorder (ASD). Here, we provide evidence from an evolutionary and neuroscience perspective about the shared mechanisms and the common roles in regulating social behaviors. We first discuss findings on the evolutionary history of oxytocin and vasopressin ligands and receptors that highlight their common origin and clarify the evolutionary background of the crosstalk between them. Second, we conducted a comprehensive review of the increasing evidence for the role of both neuropeptides in regulating social behaviors. Third, we reviewed the growing evidence on the associations between the oxytocin/vasopressin systems and ASD, which includes oxytocin and vasopressin dysfunction in animal models of autism and in human patients, and the impact of treatments targeting the oxytocin or the vasopressin systems in children and in adults. Here, we highlight the potential of targeting the oxytocin/vasopressin systems to improve social deficits observed in ASD and the need for further investigations on how to transfer these research innovations into clinical applications.

The feasibility of acupuncture as an adjunct intervention for antenatal depression: a pragmatic randomised controlled trial

BACKGROUND

Antenatal depression is common and associated with adverse consequences for mothers, babies, and future generations. Limitations with conventional approaches has resulted in additional therapies being considered. This study examined the feasibility and effectiveness of acupuncture for improving mental health.

METHODS

Fifty-seven pregnant women with depressive symptomologies were randomised to acupuncture (n=19) plus treatment as usual (TAU), progressive muscle relaxation (PMR, n=19) plus TAU or TAU (n=19). Treatments were conducted from 24 to 31 weeks gestation. Clinical assessments were performed throughout the intervention, as well as at a six-week postnatal follow-up. The primary outcome measure was depression. Secondary outcome measurements were stress, anxiety, psychological distress, quality of life and adjustment to mothering. Intention to treat (ITT), Linear Mixed Model (LMM) repeated measures and per protocol (PP) analyses were conducted.

RESULTS

At end-of-intervention there were significantly lower depression scores in the acupuncture group versus TAU and PMR respectively [ITT p<0.001, mean difference (MD) -5.84 (95% CI -9.10 to -2.58); MD -3.42 (95% CI -6.64 to -0.20)]. LMM repeated measures analysis (including postnatal follow-up) also demonstrated significantly lowered acupuncture group scores for stress (p=0.006) and psychological distress (p<0.001) when compared to PMR and TAU. Between group differences were not significant at six-weeks postnatal. No adverse events were reported.

LIMITATIONS

Main limitations are small sample size and the use of self-reported outcome measures.

CONCLUSION

Prenatal acupuncture reduced depression, stress and distress, whilst also being well-tolerated and free from adverse events. Further research is warranted.

Oxytocin receptor gene, childhood maltreatment and borderline personality disorder features among male inmates in China

BACKGROUND

Borderline personality disorder (BPD) is caused by a variety of biological and environmental factors. Accumulating evidence suggests that childhood maltreatment is a risk environmental factor in the development of BPD, but research on the genetic pathology of BPD is still in its early stages, and very little is known about the oxytocin receptor (OXTR) gene. The purpose of this study is to further explore the interactive effects between OXTR gene polymorphisms and childhood maltreatment on BPD risk.

METHODS

Among the 1804 Chinese Han male inmates, 765 inmates who had BPD or antisocial personality disorder (ASPD) or highly impulsive or violent crime were considered as high-risk inmates and included in this study. Childhood maltreatment, BPD, antisocial personality disorder (ASPD) and impulsivity were measured by self-reported questionnaires. Peripheral venous blood was collected for the genotype test.

RESULTS

Analyses revealed that the BP group (inmates with BPD features) had higher rs53576 AA genotype frequency and rs237987 AA genotype frequency than the non-BP group, while the statistical significances were lost after Bonferroni correction. Total childhood maltreatment score, emotional abuse and neglect could positively predict BPD risk. Among the high-risk samples, rs53576 GG genotype carriers had higher BPD scores at higher levels of physical abuse and sexual abuse and had lower BPD scores at lower levels of physical abuse and sexual abuse.

CONCLUSIONS

The findings suggest that the interaction between OXTR gene variations and childhood maltreatment is an important mechanism for the development of BPD. The moderating role of the OXTR gene provides evidence for gene plasticity.

Interactions of OXTR rs53576 and emotional trauma on hippocampal volumes and perceived social support in adolescent girls

Oxytocin (OXT) is a neuropeptide involved in social behaviour and is sensitive to environmental influences to alter individual vulnerability or resilience to stress resulting in both negative and positive outcomes. The effects of the OXT receptor (OXTR) single nucleotide polymorphism (SNP) rs53576 on hippocampal and amygdala structure and functions in adults are differentially associated with susceptibility to adversity and social behaviours, but this evidence is lacking in healthy adolescents. Adolescence is a developmental period characterised by neurobiological and psychosocial changes resulting in higher susceptibility to mood disorders, particularly among girls. As the brain is highly plastic at this stage, to understand psychosocial and emotional development, clarity of the interactions between rs53576 and adversity on hippocampal and amygdala volumes and social behaviours is needed. In this study, we investigated the interactions between rs53576 and emotional trauma (ET) exposure on hippocampal and amygdala volumes of adolescent girls, and associations with parenting style, perceived social support and bullying behaviour. Based on an unbiased and corrected analytical approach, we found smaller left hippocampal volumes in higher (hET) compared to minimally (mET) exposed AA homozygotes, but no differences in G allele carriers nor in the amygdala. Within the mET AA group, larger volumes were associated with peer perceived social support, but in their hET counterparts, smaller volumes were associated with familial perceived social support. This evidence supports an important role for the hippocampus in social behaviours but extends current knowledge to suggest that hippocampal social behavioural features are contextually dependent on rs53576.

A Novel Role of CD38 and Oxytocin as Tandem Molecular Moderators of Human Social Behavior

Oxytocin is an important modulator of human affiliative behaviors, including social skills, human pair bonding, and friendship. CD38 will be discussed as an immune marker and then in more detail the mechanisms of CD38 on releasing brain oxytocin. Mention is made of the paralogue of oxytocin, vasopressin, that has often overlapping and complementary functions with oxytocin on social behavior. Curiously, vasopressin does not require CD38 to be released from the brain. This review discusses the social salience hypothesis of oxytocin action, a novel view of how this molecule influences much of human social behaviors often in contradictory ways. The oxytocinergic-vasopressinergic systems are crucial modulators of broad aspects of human personality. Of special interest are studies of these two hormones in trust related behavior observed using behavioral economic games. This review also covers the role of oxytocin in parenting and parental attachment. In conclusion, the effects of oxytocin on human behavior depend on the individual's social context and importantly as well, the individual's cultural milieu, viz. East and West. ACRONYMS: ACC = Anterior Cingulate ADP = Adenosine diphosphate AQ = Autism Quotient cADPR = Cyclic ADP-ribose CNS = Central nervous system DA = Dopamine eQTLC = Expression Quantitative Trait Loci LC-NE = Locus Coeruleus-Norepinephrine MRI = Magnetic Resonance Imaging OFC = Orbitofrontal cortices OXT = Oxytocin RAGE = Receptor for advanced glycation end-products SARM1 = Sterile Alpha and toll/interleukin-1 receptor motif-containing 1 TRPM2= Transient Receptor Potential Cation Channel Subfamily M Member 2 AVP = Vasopressin.

Adrenocortical attunement, reactivity, and potential genetic correlates among parent-daughter dyads from low-income families

Examining the multitude of influences on the development of adolescent stress responses, especially among low-income families, is a critical and understudied topic in the field. The current study examined cortisol attunement between adolescent girls and parents (mostly mothers) from predominantly low-income, single parent, ethnic minority families before and after an in-laboratory disagreement discussion task. The sample consisted of 118 adolescents (M_age  = 13.79 years, 76.3% ethnic minorities, 23.7% European Americans) and primary caregivers (M_age  = 40.62 years; Mdn yearly income = $24,000; 43.2% single parents; 50% living below poverty line). We investigated oxytocin receptor (OXTR rs53576) gene variations as a potential contributor to attunement within the dyad. Results showed that parents and adolescents showed stress system attunement across the disagreement task, but that parent and adolescent oxytocin receptor genotype did not impact attunement. Future studies should detail biological factors that contribute to the calibration of stress response systems of adolescents across a variety of samples, particularly those experiencing a combination of stressors.

Positive Maternal Mental Health, Parenting, and Child Development

While maternal mental health is an important influence on child development, the existing literature focuses primarily on negative aspects of maternal mental health, particularly symptoms of depression, anxiety, or states of distress. We provide a review of the evidence on the potential importance of positive mental health for both mother and child. The evidence suggests that positive mental health is a distinct construct that is associated with improved birth outcomes and potentially with specific forms of parenting that promote both academic achievement and socioemotional function. We review studies that provide a plausible biological basis for the link between positive mental health and parenting, focusing on oxytocin-dopamine interactions. We caution that the evidence is largely preliminary and suggest directions for future research, noting the importance of identifying the operative dimensions of positive maternal mental health in relation to specific outcomes. We suggest that the inclusion of positive maternal mental health provides the potential for a more comprehensive understanding of parental influences on child development.

Maternal Neurobiological Processing of Negative Adolescent Stimuli: Relations With Positive Parenting and Relationship Quality

We examined associations between maternal affective neurobiology and positive parenting in a study of 20 mothers of adolescents. Mothers underwent functional magnetic resonance imaging during an emotion image task, rated parent-adolescent relationship quality, and completed an adolescent interaction task in which positive parenting behaviors were observed. Maternal structure was associated with lower responsivity in emotional processing regions in the general negative image contrast and was related to greater dorsolateral prefrontal cortex activation to negative adolescent images. Parent-adolescent relationship quality was associated with lower precuneus activation to negative adolescent images. Findings are among the first to connect functional brain processing with observed parenting behaviors for parents of adolescent children, and underscore the relative importance of affective processing in parenting older children.

The role of oxytocinergic genes in the intergenerational transmission of parent-child relationship qualities

Parenting qualities are known to transmit across generations, but less is known about genetic processes that may modify how strongly parenting quality carries across generations. We examined in prospective data whether oxytocinergic genes of offspring moderate the intergenerational transmission of warm and accepting parent-child relationship qualities. The sample comprised 1167 Finnish parents (G2, 62% female) and their mothers (G1). At the study baseline, G1 mothers (Mage = 38) reported parent-child relationship qualities towards G2 children (age range 3-18). After 28-34 years, G2 offspring reported parent-child relationship qualities towards their own children using the same questionnaire. A cumulative genetic score was computed for G2 by summing up previously identified four alleles associated with non-optimal parenting or social impairments across OXTR (rs1042778, rs2254298, rs53576) and CD38 (rs3796863) genes. Results indicated no interaction effects of G2 cumulative genetic score on the transmission of parent-child relationship qualities. Among single polymorphisms in OXTR, the interaction effects of rs53576 and rs1042778 were found. G1 maternal emotional warmth was associated with higher G2 emotional warmth among G2 participants with the OXTR rs53576 AA/AG genotype, but not among those with the GG genotype. G1 maternal acceptance was associated with higher G2 acceptance among those G2 participants with the OXTR rs1042778 GG/GT genotype, but not among those with the TT genotype. Oxytocinergic genes may influence sensitivity to quality of parent-child relationship, although this needs replication in future studies.

Associations between oxytocin receptor gene (OXTR) polymorphisms, childhood trauma, and parenting behavior

Maternal oxytocin is connected to aspects of parenting including sensitivity, warmth, positive affect, and affectionate touch. Oxytocin receptor gene (OXTR) polymorphisms are associated with circulating oxytocin levels, altered brain activity, and parenting behaviors. This study aimed to replicate prior work on OXTR single-nucleotide polymorphisms (SNPs) rs1042778 and rs53576 in relation to maternal sensitivity, explore associations with other aspects of parenting (i.e., negative parenting), evaluate observational and self-report measures of parenting in relation to OXTR SNPs, and examine whether childhood trauma exposure moderates the relation between OXTR SNPs and parenting. Mothers (N = 100) were observed during 2 teaching interaction tasks with their 7-month-old infant, completed questionnaire and interview measures related to parenting and trauma history, and provided saliva specimens to derive OXTR genotypes. Mothers with OXTR rs1042778 TT genotypes demonstrated lower behavioral sensitivity, lower engagement, higher intrusiveness, and more frequent frightened/frightening behavior than mothers with TG or GG genotypes. Genotype interacted with childhood trauma history such that mothers who had experienced childhood trauma were more likely to demonstrate frightened/frightening behavior if they had the TT genotype on rs1042778 relative to the TG or GG genotype; however, small cell sizes for this interaction suggest replication is warranted. Contrary to expectations, mothers with the TT genotype on rs1042778 self-reported that they had less impaired bonding than mothers with TG or GG genotypes. Results are discussed with respect to prior work with oxytocin in lower versus higher risk samples, and the potential role of mothers' self-awareness in explaining discrepancies between results from observational versus self-report measures of parenting. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Implicit associations to infant cry: Genetics and early care experiences influence caregiving propensities

Adults' sensitive appraisal of and response to infant cry play a foundational role in child development. Employing a gene × environment (G × E) approach, this study investigated the interaction of genetic polymorphisms of the serotonin transporter gene (5-HTTLPR) and oxytocin receptor genes (OXTR; rs53576, rs2254298) with early parental care experiences in influencing adults' implicit associations to infant cry. Eighty nulliparous adults (40 females, 40 males) responded to the Parental Acceptance-Rejection Questionnaire (PARQ), a measure of early care experiences, and participated in a Single Category Implicit Association Task (SC-IAT) to measure implicit associations to infant cry. Independent of parental experience, the valence of the implicit response to infant cry is associated with the serotonin transporter gene polymorphism (5-HTTLPR), with LL-carriers showing more positive implicit associations than S-carriers. OXTR rs53576 moderated the relation between parental rejection and implicit appraisal of infant cry: A-carriers who experienced negative early care showed an implicit positive appraisal of infant cry, whereas in GG carriers, positive early care experiences were associated with an implicit positive reaction to infant cry. OXTR rs2254298 had no relation to implicit associations to infant cry or to early care experiences. These findings cast light on the possible interplay of genetic inheritance and early environment in influencing adults' responses to infant cry that may be incorporated into screening protocols aimed at identifying at-risk adult-infant interactions.

Neuromodulation of maternal circuits by oxytocin

Motherhood in mammals involves tremendous changes throughout the body and central nervous system, which support attention and nurturing of infants. Maternal care consists of complex behaviors, such as nursing and protection of the offspring, requiring new mothers to become highly sensitive to infant needs. Long-lasting neural plasticity in various regions of the cerebral cortex may enable the perception and recognition of infant cues, important for appropriate caregiving responses. Recent findings have demonstrated that the neuropeptide oxytocin is involved in a number of physiological processes, including parturition and lactation and dynamically shaping neuronal responses to infant stimuli as well. Here, we review experience-dependent changes within the cortex occurring throughout motherhood, focusing on plasticity of the somatosensory and auditory cortex. We outline the role of oxytocin in gating cortical plasticity and discuss potential mechanisms regulating oxytocin release in response to different sensory stimuli.

Interaction effects of oxytocin receptor gene polymorphism and depression on hippocampal volume

Many studies have revealed that the oxytocin receptor gene (OXTR) is associated with emotional salience and depression among females. Hippocampus is closely associated with the pathophysiology of major depressive disorder (MDD). However, little is known of the interaction effects of OXTR and MDD on hippocampal volume. We sought to investigate the interaction effects of OXTR (rs53576) allelic variants and MDD on hippocampal volumes which also including subfield volumes. The OXTR rs53576 genotype groups were categorized as minor G allele carriers and A allele homozygotes. A total of 47 female patients with depression and 30 healthy females were included in this study. There were significant interactions between OXTR allele type and diagnosis of MDD on the 7 hippocampal subfield volumes, such as left presubiculum, left subiculum, left molecular, right cornus ammonis 1, right granule cells in the molecular layer of the dentate gyrus, right molecular layer, and right subiculum. There were no differences in the hippocampal volumes between MDD vs healthy controls or OXTR A vs G alleles. Our results demonstrate the importance of the interactions between OXTR and MDD on hippocampal volume. Future studies with large sample size should expand those interactions in the whole brain volumes.

Role of oxytocin in parental behaviour

Both animal and human studies have provided conclusive evidence that oxytocin (OXT) acts in the brain (eg, medial preoptic area, ventral tegmental area, nucleus accumbens) to promote parental behaviour under different reproductive and physiological conditions. OXT appears to accelerate and strengthen the neural process that makes newborns attractive or rewarding. Furthermore, OXT reduces stress/anxiety and might improve mood and well being, resulting in indirect benefits for parents. However, OXT also plays a role in the development of species reproductive and social strategies, making some species or individuals more prone to display caring activities in nonreproductive contexts. There are important differences in the development of the OXT system and its regulation by gonadal hormones that can make individuals or species very different. Those intra- and interspecific differences in the OXT system have been associated with differences in parental behaviour. For example, differences in OXT levels in body fluids and genetic variants for the OXT and OXT receptor genes have been associated with variability in parental mood and behaviour in humans. Thus, OXT has received much attention as a potential therapeutic agent for affective, emotional and behavioural problems. Despite many preliminary studies indicating promising findings, several unknown aspects of the OXT system remain to be addressed before we can achieve a complete understanding of its function in the brain. The enormous interest that this area of study has attracted in the last decade will likely continually contribute to advancing our understanding of the role of OXT in parental behaviour and other behavioural and physiological functions.

A smartphone-based ecological momentary assessment of parental behavioral consistency: Associations with parental stress and child ADHD symptoms

Inconsistent parental discipline is a robust correlate of child attention-deficit/hyperactivity disorder (ADHD) symptoms, but few studies have considered the role of inconsistent positive parenting on ADHD, as well as the effects of stress on negative and positive parental consistency. This study advanced a novel ecological momentary assessment (EMA) using participant smartphones to measure parental consistency, and examined its associations with family, social, and parenting-related dimensions of stress and child ADHD symptoms. Participants were 184 kindergartners with and without ADHD and their parents. Harsh and warm dimensions of parental behavior were assessed using questionnaires, observations, and an EMA administered through parents' smartphones, which measured parent-child behaviors every day for a period of 1 week. Family, social, and parenting-related stress were assessed from questionnaires, and child ADHD symptoms were assessed from a fully structured diagnostic interview with the parent. Child ADHD symptoms were associated with variability in warm parenting behaviors, and higher levels of parenting-related stress were related to greater variability in harsh parenting behaviors. No significant interactions were detected between parental stress and child ADHD on parental variability. These findings suggest that different factors influence the consistency in parenting behavior, depending on whether positive parenting or negative parenting is assessed. Parent-based treatment programs for children with ADHD should include a stronger focus on reducing stress from parenting (e.g., teaching coping skills for parents), as this may lead to greater consistency in parental behavior more generally, and presumably better child outcomes. (PsycINFO Database Record

Imaging genetics in autism spectrum disorders: Linking genetics and brain imaging in the pursuit of the underlying neurobiological mechanisms

Autism spectrum disorders (ASD) include a wide range of heterogeneous neurodevelopmental conditions that affect an individual in several aspects of social communication and behavior. Recent advances in molecular genetic technologies have dramatically increased our understanding of ASD etiology through the identification of several autism risk genes, most of which serve important functions in synaptic plasticity and protein synthesis. However, despite significant progress in this field of research, the characterization of the neurobiological mechanisms by which common genetic risk variants might operate to give rise to ASD symptomatology has proven to be far more difficult than expected. The imaging genetics approach holds great promise for advancing our understanding of ASD etiology by bridging the gap between genetic variations and their resultant biological effects on the brain. This paper provides a conceptual overview of the contribution of genetics in ASD and discusses key findings from the emerging field of imaging genetics.

Psychophysiological effects of oxytocin on parent-child interactions: A literature review on oxytocin and parent-child interactions

Oxytocin (OT), often called the 'hormone of love' or 'hormone of attachment,' plays a fundamental role in the establishment and quality of parent-infant bonding. However, emerging evidence indicates that OT can also produce antisocial behavior. To clarify these effects, we review studies examining the role of endogenous and exogenous OT on several determinants of attachment: parental sensitivity, and bonding or synchrony in parent-child dyads. Contextual and individual factors moderating the effect of intranasal OT and its peripheral levels are also reviewed. Finally, potential therapeutic applications for OT and current limitations in human OT research are examined. This systematic literature review was based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, with two electronic databases and other bibliographic sources. We identified a total of 47 relevant studies for inclusion in our review. Most of the findings are in accordance with recent ideas that OT administration may increase parent-child prosocial interaction, showing that OT exerts beneficial effects on processes thought to promote bonding, sensitivity, and synchrony. However, we found that OT can induce antisocial behavior (e.g., anxiety) or adverse effects (modulation of maternal care recollections) that are moderated by different contextual (e.g., maltreatment level, presence of unfamiliar people) and individual (attachment style) factors. This review reinforces the importance of context- and individual-dependent factors, which must be taken into account when analyzing the psychophysiological effects of OT.

Imaging genetics in neurodevelopmental psychopathology

Neurodevelopmental disorders are defined by highly heritable problems during development and brain growth. Attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders (ASDs), and intellectual disability (ID) are frequent neurodevelopmental disorders, with common comorbidity among them. Imaging genetics studies on the role of disease-linked genetic variants on brain structure and function have been performed to unravel the etiology of these disorders. Here, we reviewed imaging genetics literature on these disorders attempting to understand the mechanisms of individual disorders and their clinical overlap. For ADHD and ASD, we selected replicated candidate genes implicated through common genetic variants. For ID, which is mainly caused by rare variants, we included genes for relatively frequent forms of ID occurring comorbid with ADHD or ASD. We reviewed case-control studies and studies of risk variants in healthy individuals. Imaging genetics studies for ADHD were retrieved for SLC6A3/DAT1, DRD2, DRD4, NOS1, and SLC6A4/5HTT. For ASD, studies on CNTNAP2, MET, OXTR, and SLC6A4/5HTT were found. For ID, we reviewed the genes FMR1, TSC1 and TSC2, NF1, and MECP2. Alterations in brain volume, activity, and connectivity were observed. Several findings were consistent across studies, implicating, for example, SLC6A4/5HTT in brain activation and functional connectivity related to emotion regulation. However, many studies had small sample sizes, and hypothesis-based, brain region-specific studies were common. Results from available studies confirm that imaging genetics can provide insight into the link between genes, disease-related behavior, and the brain. However, the field is still in its early stages, and conclusions about shared mechanisms cannot yet be drawn.

Neural correlates of babyish adult face processing in men

The morphological characteristics of an infant's face are collectively referred to as baby schema or babyishness. It has been well established that infant traits are implicitly projected, or overgeneralized, to adults with babyish facial features. However, few studies to date have investigated the neural underpinnings of such overgeneralization. In the present study, we addressed this issue by comparing neural activations elicited by baby-faced and mature-faced adult faces in men using fMRI. We found increased activations in clusters surrounding the bilateral insula, bilateral anterior cingulate cortex, and right inferior frontal gyrus, which have been previously linked to the processing of facial attractiveness and infant-related information. We also discovered increased activation in the left medial prefrontal cortex, which might be related to emotional or empathic responses directed towards baby-faced adults. The activated region also included the left premotor cortex, which presumably reflects an embodied response or approach motivation directed toward infant-related information. Furthermore, the activation level of the left caudate correlated with the salivary concentration of oxytocin. Taken together, these findings indicate that passive viewing of babyish adult faces induces increased responses in neural regions linked to facial attractiveness and infant-related information processing, and that these responses are partially influenced by oxytocinergic factors.

Common variant in OXTR predicts growth in positive emotions from loving-kindness training

Ample research suggests that social connection reliably generates positive emotions. Oxytocin, a neuropeptide implicated in social cognition and behavior, is one biological mechanism that may influence an individual's capacity to extract positive emotions from social contexts. Because variation in certain genes may indicate underlying neurobiological differences, we tested whether several SNPs in two genes related to oxytocin signaling would show effects on positive emotions that were context-specific, depending on sociality. For six weeks, a sample of mid-life adults (N=122) participated in either socially-focused loving-kindness training or mindfulness training. During this timespan they reported their positive emotions daily. Five SNPs within OXTR and CD38 were assayed, and each was tested for its individual effect on daily emotions. The hypothesized three-way interaction between time, training type, and genetic variability emerged: Individuals homozygous for the G allele of OXTR rs1042778 experienced gains in daily positive emotions from loving-kindness training, whereas individuals with the T allele did not experience gains in positive emotions with either training. These findings are among the first to show how genetic differences in oxytocin signaling may influence an individual's capacity to experience positive emotions as a result of a socially-focused intervention.

The endocrinology of human caregiving and its intergenerational transmission

Variation in the quality of parental care has a tremendous impact on a child's social–emotional development. Research investigating the predictors of this variability in human caregiving behavior has mostly focused on learning mechanisms. Evidence is currently accumulating for the complementary underlying role of steroid hormones and neuropeptides. An overview is provided of the hormones and neuropeptides relevant for human caregiving behavior. Then the developmental factors are described that stimulate variability in sensitivity to these hormones and neuropeptides, which may result in variability in the behavioral repertoire of caregiving. The role of genetic variation in neuropeptide and steroid receptors, the role of testosterone and oxytocin during fetal development and parturition, and the impact of experienced caregiving in childhood on functioning of the neuroendocrine stress and oxytocin system are discussed. Besides providing a heuristic framework for further research on the ontogenetic development of human caregiving, a neuroendocrine model is also presented for the intergenerational transmission of caregiving practices. Insight into the underlying biological mechanisms that bring about maladaptive caregiving behavior, such as neglect and insensitive parenting, will hopefully result in more efficient approaches to reduce the high prevalence of such behavior and to minimize the impact on those affected.

Implicit association to infant faces: Genetics, early care experiences, and cultural factors influence caregiving propensities

Genetics, early experience, and culture shape caregiving, but it is still not clear how genetics, early experiences, and cultural factors might interact to influence specific caregiving propensities, such as adult responsiveness to infant cues. To address this gap, 80 Italian adults (50% M; 18-25 years) were (1) genotyped for two oxytocin receptor gene polymorphisms (rs53576 and rs2254298) and the serotonin transporter gene polymorphism (5-HTTLPR), which are implicated in parenting behaviour, (2) completed the Adult Parental Acceptance/Rejection Questionnaire to evaluate their recollections of parental behaviours toward them in childhood, and (3) were administered a Single Category Implicit Association Test to evaluate their implicit responses to faces of Italian infants, Japanese infants, and Italian adults. Analysis of implicit associations revealed that Italian infant faces were evaluated as most positive; participants in the rs53576 GG group had the most positive implicit associations to Italian infant faces; the serotonin polymorphism moderated the effect of early care experiences on adults' implicit association to both Italian infant and adult female faces. Finally, 5-HTTLPR S carriers showed less positive implicit responses to Japanese infant faces. We conclude that adult in-group preference extends to in-group infant faces and that implicit responses to social cues are influenced by interactions of genetics, early care experiences, and cultural factors. These findings have implications for understanding processes that regulate adult caregiving.

Youth temperament, harsh parenting, and variation in the oxytocin receptor gene forecast allostatic load during emerging adulthood

An association has been found between receipt of harsh parenting in childhood and adult health problems. However, this research has been principally retrospective, has treated children as passive recipients of parental behavior, and has overlooked individual differences in youth responsivity to harsh parenting. In a 10-year multiple-wave prospective study of African American families, we addressed these issues by focusing on the influence of polymorphisms in the oxytocin receptor gene (OXTR), variants of which appear to buffer or amplify responses to environmental stress. The participants were 303 youths, with a mean age of 11.2 at the first assessment, and their parents, all of whom were genotyped for variations in the rs53576 (A/G) polymorphism. Teachers rated preadolescent (ages 11 to 13) emotionally intense and distractible temperaments, and adolescents (ages 15 and 16) reported receipt of harsh parenting. Allostatic load was assessed during young adulthood (ages 20 and 21). Difficult preadolescent temperament forecast elevated receipt of harsh parenting in adolescence, and adolescents who experienced harsh parenting evinced high allostatic load during young adulthood. However, these associations emerged only among children and parents who carried A alleles of the OXTR genotype. The results suggest the oxytocin system operates along with temperament and parenting to forecast young adults' allostatic load.

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).

Neural responses to maternal praise and criticism: Relationship to depression and anxiety symptoms in high-risk adolescent girls

Background

The parent-child relationship may be an important factor in the development of adolescent depressive and anxious symptoms. In adults, depressive symptoms relate to increased amygdala and attenuated prefrontal activation to maternal criticism. The current pilot study examined how depressive and anxiety symptoms in a high-risk adolescent population relate to neural responses to maternal feedback. Given previous research relating oxytocin to maternal behavior, we conducted exploratory analyses using oxytocin receptor (OXTR) genotype.

Methods

Eighteen females (ages 12–16) listened to maternal praise, neutral, and critical statements during functional magnetic resonance imaging. Participants completed the Mood and Feelings Questionnaire and the Screen for Child Anxiety Related Emotional Disorders. The OXTR single nucleotide polymorphism, rs53576, was genotyped. Linear mixed models were used to identify symptom or allele (GG, AA/AG) by condition (critical, neutral, praise) interaction effects on brain activation.

Results

Greater symptoms related to greater right amygdala activation for criticism and reduced activation to praise. For left amygdala, greater symptoms related to reduced activation to both conditions. Anxiety symptoms related to differences in superior medial PFC activation patterns. Parental OXTR AA/AG allele related to reduced activation to criticism and greater activation to praise within the right amygdala.

Conclusions

Results support a relationship between anxiety and depressive symptoms and prefrontal-amygdala responses to maternal feedback. The lateralization of amygdala findings suggests separate neural targets for interventions reducing reactivity to negative feedback or increasing salience of positive feedback. Exploratory analyses suggest that parents' OXTR genetic profile influences parent-child interactions and related adolescent brain responses.

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Adolescent brain responses to maternal praise and criticism were examined.

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Anxiety related to prefrontal-amygdala response to both criticism and praise.

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Exploratory results support a role for the OXTR gene in parent-child interactions.

Oxytocin and parent-child interaction in the development of empathy among children at risk for autism

This longitudinal study investigated whether variation in the oxytocin receptor gene (OXTR) and early parent-child interactions predicted later empathic behavior in 84 toddlers at high or low familial risk for autism spectrum disorder. Two well-studied OXTR single-nucleotide polymorphisms, rs53576 and rs2254298, were examined. Parent-child interaction was measured at 15 and 18 months of age during free play sessions. Empathy was measured at 24 and 30 months using a response to parental distress paradigm. While there was no direct association between parent-child interaction quality or OXTR and empathy, rs53576 moderated the relation between interaction quality and empathy. Results suggest that the interplay between OXTR and early parent-child interactions predicts individual differences in empathy in children at varying risk for atypical social development. Findings are consonant with a differential susceptibility model in which an OXTR variant may increase the social salience of interaction processes for specific allele carriers. These results increase our understanding of predictors of empathy development in young children with a wide range of social outcomes. (PsycINFO Database Record

Interpreting infant emotional expressions: Parenthood has differential effects on men and women

Interpreting and responding to an infant's emotional cues is a fundamental parenting skill. Responsivity to infant cues is frequently disrupted in depression, impacting negatively on child outcomes, which underscores its importance. It is widely assumed that women, and in particular mothers, show greater attunement to infants than do men. However, empirical evidence for sex and parental status effects, particularly in relation to perception of infant emotion, has been lacking. In this study, men and women with and without young infants were asked to rate valence in a range of infant facial expressions, on a scale of very positive to very negative. Results suggested complex interaction effects between parental status, sex, and the facial expression being rated. Mothers provided more positive ratings of the happy expressions and more extreme ratings of the intense emotion expressions than fathers, but non-mothers and non-fathers did not. Low-level depressive symptoms were also found to correlate with more negative ratings of negative infant facial expressions across the entire sample. Overall, these results suggest that parental status might have differential effects on men and women's appraisal of infant cues. Differences between fathers' and mothers' perceptions of infant emotion might be of interest in understanding variance in interaction styles, such as proportion of time spent in play.

Delay discounting, genetic sensitivity, and leukocyte telomere length

In a graying world, there is an increasing interest in correlates of aging, especially those found in early life. Leukocyte telomere length (LTL) is an emerging marker of aging at the cellular level, but little is known regarding its link with poor decision making that often entails being overly impatient. Here we investigate the relationship between LTL and the degree of impatience, which is measured in the laboratory using an incentivized delay discounting task. In a sample of 1,158 Han Chinese undergraduates, we observe that steeper delay discounting, indexing higher degree of impatience, is negatively associated with LTL. The relationship is robust after controlling for health-related variables, as well as risk attitude-another important determinant of decision making. LTL in females is more sensitive to impatience than in males. We then asked if genes possibly modulate the effect of impatient behavior on LTL. The oxytocin receptor gene (OXTR) polymorphism rs53576, which has figured prominently in investigations of social cognition and psychological resources, and the estrogen receptor β gene (ESR2) polymorphism rs2978381, one of two gonadal sex hormone genes, significantly mitigate the negative effect of impatience on cellular aging in females. The current results contribute to understanding the relationship between preferences in decision making, particularly impatience, and cellular aging, for the first time to our knowledge. Notably, oxytocin and estrogen receptor polymorphisms temper accelerated cellular aging in young females who tend to make impatient choices.

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

Oxytocin (OT), a nonapeptide signaling molecule originating from an ancestral peptide, appears in different variants across all vertebrate and several invertebrate species. Throughout animal evolution, neuropeptidergic signaling has been adapted by organisms for regulating response to rapidly changing environments. The family of OT-like molecules affects both peripheral tissues implicated in reproduction, homeostasis, and energy balance, as well as neuromodulation of social behavior, stress regulation, and associative learning in species ranging from nematodes to humans. After describing the OT-signaling pathway, we review research on the three genes most extensively studied in humans: the OT receptor (OXTR), the structural gene for OT (OXT/neurophysin-I), and CD38. Consistent with the notion that sociality should be studied from the perspective of social life at the species level, we address human social functions in relation to OT-pathway genes, including parenting, empathy, and using social relationships to manage stress. We then describe associations between OT-pathway genes with psychopathologies involving social dysfunctions such as autism, depression, or schizophrenia. Human research particularly underscored the involvement of two OXTR single nucleotide polymorphisms (rs53576, rs2254298) with fewer studies focusing on other OXTR (rs7632287, rs1042778, rs2268494, rs2268490), OXT (rs2740210, rs4813627, rs4813625), and CD38 (rs3796863, rs6449197) single nucleotide polymorphisms. Overall, studies provide evidence for the involvement of OT-pathway genes in human social functions but also suggest that factors such as gender, culture, and early environment often confound attempts to replicate first findings. We conclude by discussing epigenetics, conceptual implications within an evolutionary perspective, and future directions, especially the need to refine phenotypes, carefully characterize early environments, and integrate observations of social behavior across ecological contexts.

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

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

The maternal brain and its plasticity in humans

This article is part of a Special Issue "Parental Care". Early mother-infant relationships play important roles in infants' optimal development. New mothers undergo neurobiological changes that support developing mother-infant relationships regardless of great individual differences in those relationships. In this article, we review the neural plasticity in human mothers' brains based on functional magnetic resonance imaging (fMRI) studies. First, we review the neural circuits that are involved in establishing and maintaining mother-infant relationships. Second, we discuss early postpartum factors (e.g., birth and feeding methods, hormones, and parental sensitivity) that are associated with individual differences in maternal brain neuroplasticity. Third, we discuss abnormal changes in the maternal brain related to psychopathology (i.e., postpartum depression, posttraumatic stress disorder, substance abuse) and potential brain remodeling associated with interventions. Last, we highlight potentially important future research directions to better understand normative changes in the maternal brain and risks for abnormal changes that may disrupt early mother-infant relationships.

Neuroanatomical and neurochemical basis of parenting: Dynamic coordination of motivational, affective and cognitive processes

This article is part of a Special Issue "Parental Care". Becoming a parent is arguably the most profound transforming experience in life. It is also inherently very emotionally and physically demanding, such that the reciprocal interaction with the young changes the brain and behavior of the parents. In this review, we examine the neurobiological mechanisms of parenting primarily discussing recent research findings in rodents and primates, especially humans. We argue that it is essential to consider parenting within a conceptual framework that recognizes the dynamics of the reciprocal mother-young relationship, including both the complexity and neuroplasticity of its underlying mechanisms. Converging research suggests that the concerted activity of a distributed network of subcortical and cortical brain structures regulates different key aspects of parenting, including the sensory analysis of infant stimuli as well as motivational, affective and cognitive processes. The interplay among these processes depends on the action of various neurotransmitters and hormones that modulate the timely and coordinated execution of caregiving responses of the maternal circuitry exquisitely attuned to the young's affect, needs and developmental stage. We conclude with a summary and a set of questions that may guide future research.

Genetic mechanisms of parenting

This article is part of a Special Issue "Parental Care". The complexities of parenting behavior in humans have been studied for decades. Only recently did we begin to probe the genetic and epigenetic mechanisms underlying these complexities. Much of the research in this field continues to be informed by animal studies, where genetic manipulations and invasive tools allow to peek into and directly observe the brain during the expression of maternal behavior. In humans, studies of adult twins who are parents can suggest dimensions of parenting that might be more amenable to a genetic influence. Candidate gene studies can test specific genes in association with parental behavior based on prior knowledge of those genes' function. Gene-by-environment interactions of a specific kind indicating differential susceptibility to the environment might explain why some parents are more resilient and others are more vulnerable to stressful life events. Epigenetic studies can provide the bridge often necessary to explain why some individuals behave differently from others despite common genetic influences. There is a much-needed expansion in parenting research to include not only mothers as the focus-as has been the case almost exclusively to date-but also fathers, grandparents, and other caregivers.

Gene-environment interaction between the oxytocin receptor (OXTR) gene and parenting behaviour on children's theory of mind

Theory of mind (ToM) is the ability to interpret and understand human behaviour by representing the mental states of others. Like many human capacities, ToM is thought to develop through both complex biological and socialization mechanisms. However, no study has examined the joint effect of genetic and environmental influences on ToM. This study examined how variability in the oxytocin receptor gene (OXTR) and parenting behavior--two widely studied factors in ToM development-interacted to predict ToM in pre-school-aged children. Participants were 301 children who were part of an ongoing longitudinal birth cohort study. ToM was assessed at age 4.5 using a previously validated scale. Parenting was assessed through observations of mothers' cognitively sensitive behaviours. Using a family-based association design, it was suggestive that a particular variant (rs11131149) interacted with maternal cognitive sensitivity on children's ToM (P = 0.019). More copies of the major allele were associated with higher ToM as a function of increasing cognitive sensitivity. A sizeable 26% of the variability in ToM was accounted for by this interaction. This study provides the first empirical evidence of gene-environment interactions on ToM, supporting the notion that genetic factors may be modulated by potent environmental influences early in development.

Parenting begets parenting: A neurobiological perspective on early adversity and the transmission of parenting styles across generations

The developing brains of young children are highly sensitive to input from their social environment. Nurturing social experience during this time promotes the acquisition of social and cognitive skills and emotional competencies. However, many young children are confronted with obstacles to healthy development, including poverty, inappropriate care, and violence, and their enhanced sensitivity to the social environment means that they are highly susceptible to these adverse childhood experiences. One source of social adversity in early life can stem from parenting that is harsh, inconsistent, non-sensitive or hostile. Parenting is considered to be the cornerstone of early socio-emotional development and an adverse parenting style is associated with adjustment problems and a higher risk of developing mood and behavioral disorders. Importantly, there is a growing literature showing that an important predictor of parenting behavior is how parents, especially mothers, were parented themselves. In this review, we examine how adversity in early-life affects mothering behavior in later-life and how these effects may be perpetuated inter-generationally. Relying on studies in humans and animal models, we consider evidence for the intergenerational transmission of mothering styles. We then describe the psychological underpinnings of mothering, including responsiveness to young, executive function and affect, as well as the physiological mediators of mothering behavior, including hormones, brain regions and neurotransmitters, and we consider how development in these relevant domains may be affected by adversity experienced in early life. Finally, we explore how genes and early experience interact to predict mothering behavior, including the involvement of epigenetic mechanisms. Understanding how adverse parenting begets adverse parenting in the next generation is critical for designing interventions aimed at preventing this intergenerational cycle of early adversity.

Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations

Maternal care decision rules should evolve responsiveness to factors impinging on the fitness pay-offs of care. Because the caretaking environments common in industrialized and small-scale societies vary in predictable ways, we hypothesize that heuristics guiding maternal behaviour will also differ between these two types of populations. We used a factorial vignette experiment to elicit third-party judgements about likely caretaking decisions of a hypothetical mother and her child when various fitness-relevant factors (maternal age and access to resources, and offspring age, sex and quality) were varied systematically in seven populations-three industrialized and four small-scale. Despite considerable variation in responses, we found that three of five main effects, and the two severity effects, exhibited statistically significant industrialized/ small-scale population differences. All differences could be explained as adaptive solutions to industrialized versus small-scale caretaking environments. Further, we found gradients in the relationship between the population-specific estimates and national-level socio-economic indicators, further implicating important aspects of the variation in industrialized and small-scale caretaking environments in shaping heuristics. Although there is mounting evidence for a genetic component to human maternal behaviour, there is no current evidence for interpopulation variation in candidate genes. We nonetheless suggest that heuristics guiding maternal behaviour in diverse societies emerge via convergent evolution in response to similar selective pressures.