The neural mechanisms and consequences of paternal caregiving

Single-Cell Peptide Profiling to Distinguish Stickleback Ecotypes with Divergent Breeding Behavior

Variation in parenting behavior is widespread across the animal kingdom, both within and between species. There are two ecotypes of the three-spined stickleback fish (Gasterosteus aculeatus) that exhibit dramatic differences in their paternal behavior. Males of the common ecotype are highly attentive fathers, tending to young from eggs to fry, while males of the white ecotype desert offspring as eggs. As the pituitary is a key regulator in the hypothalamic-pituitary-adrenal (HPA) axis and the hypothalamic-pituitary-gonadal (HPG) axis between the brain and body, its peptides may influence parenting behaviors. Here, we utilized matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) for high-throughput peptide analysis in single cells of pituitaries from both three-spined stickleback ecotypes. Peptide mass fingerprinting was performed using an in silico generated peptide library to identify detected prohormones. Differential analysis revealed POMC-derived peptides, MCH-derived peptides, and oxytocin as significantly different between the two ecotypes, with higher oxytocin levels in the common ecotype. Interestingly, these subtle chemical differences were not captured by Leiden clustering of the cellular phenotypes. These results call for further investigation of the neurochemical basis for parenting in sticklebacks.

Childhood heart disease and parental emotional wellbeing: a predictive model to explain the perception of quality of life in children and adolescents

BACKGROUND

The number of people living with congenital heart disease (CHD) in 2017 was estimated to be 12 million, which was 19% higher than that in 1990. However, their death rate declined by 35%, emphasizing the importance of monitoring their quality of life due to its impact on several patient outcomes. The main objective of this study is to analyze how parents' psychosocial factors contribute to children's and adolescents' perceptions of their QoL, focusing on their medical condition. More specifically, we explore how parental psychological dimensions, such as anxiety and depression, are related to patients' health-related quality of life (HRQoL).

METHODS

We recruited 447 children aged 5 to 18 years with a CHD diagnosis and their parents (319 mothers and 229 fathers) from January to December 2018. Patients were referred to the Cardiology Department of "Bambino Gesù" Children's Hospital and participated in multidisciplinary standardized follow-up. Children and adolescents were submitted to a comprehensive evaluation by different physicians, including pediatric cardiologists, surgeons, and psychologists, at preset time frames. A series of standardized questionnaires were administered during psychological assessment.

RESULTS

The main findings show a negative correlation between mothers' anxiety and three patients' HRQoL subscales (Treatment II, Treatment anxiety, and Communication). Similarly, mothers' depression correlates negatively with other patients' HRQoL subscales (heart problems, symptoms, perceived physical appearance, cognitive problems, and communication). Fathers' anxiety and depression show negative correlations with only the subscale of Treatment II. More generally, the perceived quality of life of children and adolescents with CHD is influenced by their medical conditions as well as the parents' psychological dimensions.

CONCLUSIONS

Our findings suggest that the caregivers of pediatric patients with CHD are more exposed to psychological problems of anxiety and depression, which affect the perceived quality of life of their children. Longitudinal research with a healthy control group is recommended to further consolidate this evidence.

How the Paternal Brain Is Wired by Pregnancy

This Viewpoint describes morphologic and functional changes in the paternal brain after childbirth.

Caregiver or Playmate? Fathers' and mothers' brain responses to ball-play with children

Parents and children often engage in joint play-a domain where mothers and fathers are thought to exhibit disparate behaviors and impact child development via distinct mechanisms. However, little is known about the neural substrates of mother-child and father-child play. In this fMRI study, we sampled the brain activation of parents of preschoolers (N = 88) during a novel event-related adaptation of the virtual ball-tossing game "Cyberball." Mothers (N = 40) and fathers (N = 48) played "Cyberball" ostensibly with their own and an unrelated child, who consecutively included, excluded, and reincluded parents. We found that overall, exclusion yielded comparable neural activations in mothers and fathers associated with mentalizing, saliency, and emotion processing. We also observed a parent gender effect in several brain areas. While mothers exhibited increased reward- and attention-related activity during inclusion, fathers displayed increased mentalizing-related activity during exclusion. Furthermore, we tested parents' response to reinclusion, which revealed a selective decrease in reward-related activity. Finally, exploratory analyses showed that parental involvement was positively correlated with parental brain activity within attention- and mentalizing-related areas during inclusion, as opposed to other game phases, and that an anxious parenting style was associated with increased neural sensitivity for game events involving their own child. Overall, our study elucidates the common and distinct neural networks that mothers and fathers engage during play interactions with their children, supporting theories that postulate only a partial differentiation of paternal and maternal parenting systems.

Genetics of female and male reproductive traits and their relationship with health, longevity and consequences for offspring

Substantial shifts in reproductive behaviors have recently taken place in many high-income countries including earlier age at menarche, advanced age at childbearing, rising childlessness and a lower number of children. As reproduction shifts to later ages, genetic factors may become increasingly important. Although monogenic genetic effects are known, the genetics underlying human reproductive traits are complex, with both causal effects and statistical bias often confounded by socioeconomic factors. Here, we review genome-wide association studies (GWASs) of 44 reproductive traits of both female and male individuals from 2007 to early 2024, examining reproductive behavior, reproductive lifespan and aging, infertility and hormonal concentration. Using the GWAS Catalog as a basis, from 159 relevant studies, we isolate 37 genes that harbor association signals for four or more reproductive traits, more than half of which are linked to rare Mendelian disorders, including ten genes linked to reproductive-related disorders: FSHB, MCM8, DNAH2, WNT4, ESR1, IGSF1, THRB, BRWD1, CYP19A1 and PTPRF. We also review the relationship of reproductive genetics to related health and behavioral traits, aging and longevity and the effect of parental age on offspring outcomes as well as reflecting on limitations, open questions and challenges in this fast-moving field.

Environmental sensitivity moderates the longitudinal effect of fathers' positive parenting on mental disorders in Chinese adolescents

BACKGROUND

Exposure to fathers' positive parenting has been associated reducing mental disorder symptoms during adolescence, evidence on the mechanisms underlying this association is lacking. One potential mechanism linking fathers' positive parenting and mental disorders is environmental sensitivity (ES). Here we studied whether the increased positive behaviors of both parents (1) separately, (2) relatively, (3) and jointly predict reduced depression, attention deficit hyperactivity disorder (ADHD) symptoms, suicidal ideation (SI), and increased well-being in Chinese adolescents. Additionally we investigated (4) whether ES moderates these relationships.

METHODS

This study involving 7010 Chinese adolescents (55.6 % girls) aged 15 to 18 from six junior high schools in Shaanxi, China was conducted at four timepoints. ES was assessed using the Highly Sensitive Child (HSC) scale at ages 15 and 16, parental positive behaviors using the Parental Bonding Instrument (PBI) at ages 16 and 17, and psychopathology symptoms using the 9-item Patient Health Questionnaire (PHQ-9), Strengths and Difficulties Questionnaire (SDQ), and Positive and Negative Suicide Ideation (PANSI) Inventory at ages 17 and 18.

RESULTS

(1) Multilevel analyses revealed that increased positive parenting predicted reduced psychiatric disorder symptoms and improved well-being; (2) trend interaction indicated that the compensatory effect of fathers' positive parenting was stronger in alleviating mental problems in adolescents than that of mothers'; (3) Simple slope analyses suggested that both high levels of fathers' and mothers' positive parenting predicted fewer subsequent psychiatric disorder symptoms, particularly for sensitive adolescents.

LIMITATIONS

This study was limited to its generalizability to the Western Chinese adolescents.

CONCLUSIONS

Substantial differences in the effects of positive paternal and maternal parenting highlight the important role of fathers' positive parenting in mental development, especially for highly sensitive adolescents.

The parental brain, perinatal mental illness, and treatment: A review of key structural and functional changes

The transition to parenthood is perhaps the only time in adult life when the brain changes to such a significant degree in such a short period, particularly in birthing parents. It is also a time when there is an increased risk of developing a mental illness, which may be due, in part, to the increased neuroplasticity. Thus, we must develop interventions and treatments that support parents and promote parental brain health. This review will highlight key findings from current research on how human brain structure and function are modified with 1) the transition to parenthood, 2) parenting stress and perinatal mental illness, and 3) treatments aimed at promoting perinatal mental health. The focus will be on birthing parents and mothers, but brain changes in non-birthing parents will also be discussed. Improvements in our understanding of the parental brain, in health and with illness, will promote the well-being of generations to come.

Neurobiological mechanisms underlying oxytocin-mediated parental behavior in rodents

Parental behavior is essential for mammalian offspring to survive. Because of this significance, elucidating the neurobiological mechanisms that facilitate parental behavior has received strong interest. Decades of studies utilizing pharmacology and molecular biology have revealed that in addition to its facilitatory effects on parturition and lactation, oxytocin (OT) promotes the expression of parental behavior in rodents. Recent studies have also described the modulation of sensory processing by OT and the interaction of the OT system with other brain regions associated with parental behavior. However, the precise neurobiological mechanisms underlying the facilitation of caregiving behaviors by OT remain unclear. In this Review, I summarize the findings from rats and mice with a view toward integrating past and recent progress. I then review recent advances in the understanding of the molecular, cellular, and circuit mechanisms of OT-mediated parental behavior. Based on these observations, I propose a hypothetical model that would explain the mechanisms underlying OT-mediated parental behavior. Finally, I conclude by discussing some major remaining questions and propose potential future research directions.

Enduring maternal brain changes and their role in mediating motherhood's impact on well-being

Parenthood, particularly motherhood, is known to impact the structure and function of the brain in the short term, but the long-term effects of parenthood and their impacts on well-being are still poorly understood. This study explores the potential longer-term associations between parenthood and the brain, parenthood and well-being, and the potential role of brain modifications in influencing mothers' well-being. Using data from the UK Biobank, which includes brain imaging information from individuals aged 45-82 at the MRI scanning, we discovered differences in brain structure between mothers and non-mothers, with mothers exhibiting widely distributed higher gray matter density, particularly strong in frontal and occipital regions. No brain changes were observed in fathers. Parents reported a higher sense of life's meaning compared to their childless counterparts. Gray matter changes did not mediate the relationship between motherhood and well-being. This suggests that the alterations in gray matter associated with motherhood do not play a deterministic role in shaping long-term changes in well-being.

Parental status and markers of brain and cellular age: A 3D convolutional network and classification study

Recent research shows prominent effects of pregnancy and the parenthood transition on structural brain characteristics in humans. Here, we present a comprehensive study of how parental status and number of children born/fathered links to markers of brain and cellular ageing in 36,323 UK Biobank participants (age range 44.57-82.06 years; 52% female). To assess global effects of parenting on the brain, we trained a 3D convolutional neural network on T1-weighted magnetic resonance images, and estimated brain age in a held-out test set. To investigate regional specificity, we extracted cortical and subcortical volumes using FreeSurfer, and ran hierarchical clustering to group regional volumes based on covariance. Leukocyte telomere length (LTL) derived from DNA was used as a marker of cellular ageing. We employed linear regression models to assess relationships between number of children, brain age, regional brain volumes, and LTL, and included interaction terms to probe sex differences in associations. Lastly, we used the brain measures and LTL as features in binary classification models, to determine if markers of brain and cellular ageing could predict parental status. The results showed associations between a greater number of children born/fathered and younger brain age in both females and males, with stronger effects observed in females. Volume-based analyses showed maternal effects in striatal and limbic regions, which were not evident in fathers. We found no evidence for associations between number of children and LTL. Classification of parental status showed an Area under the ROC Curve (AUC) of 0.57 for the brain age model, while the models using regional brain volumes and LTL as predictors showed AUCs of 0.52. Our findings align with previous population-based studies of middle- and older-aged parents, revealing subtle but significant associations between parental experience and neuroimaging-based surrogate markers of brain health. The findings further corroborate results from longitudinal cohort studies following parents across pregnancy and postpartum, potentially indicating that the parenthood transition is associated with long-term influences on brain health.

Protective role of parenthood on age-related brain function in mid- to late-life

The experience of parenthood can profoundly alter one's body, mind, and environment, yet we know little about the long-term associations between parenthood and brain function and aging in adulthood. Here, we investigate the link between number of children parented (parity) and age on brain function in 19,964 females and 17,607 males from the UK Biobank. In both females and males, increased parity was positively associated with functional connectivity, particularly within the somato/motor network. Critically, the spatial topography of parity-linked effects was inversely correlated with the impact of age on functional connectivity across the brain for both females and males, suggesting that a higher number of children is associated with patterns of brain function in the opposite direction to age-related alterations. These results indicate that the changes accompanying parenthood may confer benefits to brain health across the lifespan, highlighting the importance of future work to understand the associated mechanisms.

COMFORTneo scale in preterm infants during live performed music therapy-Difference between close physical contact and hand touch contact

There is evidence that music therapy combined with physical contact to parents stabilizes the vital signs of hospitalized preterm infants. Yet, there is no evidence for the difference between simple contact by touching the infant in the incubator or cod, or close physical contact during music therapy sessions (MT). Behavioral effects of the various forms of attention toward the infant during therapy need to be elucidated. Our study aimed to quantify the effects of hand touch contact (HTC) and close physical contact (CPC) during live performed MT in preterm infants regardless of gestational age on behavioral state (assessed via COMFORTneo scale) and vital signs. A maximum of ten live music therapy sessions were delivered three to four times a week until hospital discharge to 50 stable infants. Pre-, during- and post-therapy heart rates, respiratory rates, oxygen saturations and COMFORTneo scores were recorded for each session. A total of 486 sessions was performed with 243 sessions using HTC and CPC each. The mean gestational age was 33 + 3 weeks, with 27 (54%) infants being male. We observed lower COMFORTneo scores, heart and respiratory rates and higher oxygen saturation during and after live performed music therapy independent of the kind of physical contact than before therapy. While pre-therapy values were better in the CPC group for all four variables, a higher mean response on COMFORTneo scale and vital signs was observed for HTC (COMFORTneo score -5.5, heart rate -12.4 beats per min., respiratory rate -8.9 breaths per min, oxygen saturation + 1.5%) compared to CPC (COMFORTneo score -4.6, heart rate -9.6 beats per min., respiratory rate -7.0 breaths per min, oxygen saturation + 1.1%). Nonetheless, post-therapy values were better for all four measures in the CPC group. Regression modeling with correction for individual responses within each patient also yielded attenuated effects of MT in the CPC group compared to HTC, likely caused by the improved pre-therapy values. Live performed music therapy benefits preterm infants' vital signs and behavioral state. During CPC with a parent, the absolute therapeutic effect is attenuated but resulting post-therapy values are nonetheless better for both the COMFORTneo scale and vital signs.

Mothers and fathers show different neural synchrony with their children during shared experiences

Parent-child shared experiences has an important influence on social development in children although contributions of mothers and fathers may differ. Neural synchronicity occurs between mothers and fathers and their children during social interactions but it is unclear whether they differ in this respect. We used data from simultaneous fNIRS hyperscanning in mothers (n = 33) and fathers (n = 29) and their children (3-4 years) to determine different patterns and strengths of neural synchronization in the frontal cortex during co-viewing of videos or free-play. Mothers showed greater synchrony with child than fathers during passive viewing of videos and the synchronization was positively associated with video complexity and negatively associated with parental stress. During play interactions, mothers showed more controlling behaviors over their child and greater evidence for joint gaze and joint imitation play with child whereas fathers spent more time gazing at other things. In addition, different aspects of child communication promoted neural synchrony between mothers and fathers and child during active play interactions. Overall, our findings indicate greater neural and behavioral synchrony between mothers than fathers and young children during passive or active shared experiences, although for both it was weakened by parental distress and child difficulty.

Legacies of salient environmental experiences-insights from chemosensation

Evidence for parental environments profoundly influencing the physiology, biology, and neurobiology of future generations has been accumulating in the literature. Recent efforts to understand this phenomenon and its underlying mechanisms have sought to use species like rodents and insects to model multi-generational legacies of parental experiences like stress and nutritional exposures. From these studies, we have come to appreciate that parental exposure to salient environmental experiences impacts the cadence of brain development, hormonal responses to stress, and the expression of genes that govern cellular responses to stress in offspring. Recent studies using chemosensory exposure have emerged as a powerful tool to shed new light on how future generations come to be influenced by environments to which parents are exposed. With a specific focus on studies that have leveraged such use of salient chemosensory experiences, this review synthesizes our current understanding of the concept, causes, and consequences of the inheritance of chemosensory legacies by future generations and how this field of inquiry informs the larger picture of how parental experiences can influence offspring biology.

Father contribution to human resilience

Fathers have been an important source of child endurance and prosperity since the dawn of civilization, promoting adaptation to social rules, defining cultural meaning systems, teaching daily living skills, and providing the material background against which children developed; still, the recent reformulation in the role of the father requires theory-building. Paternal caregiving is rare in mammals, occurring in 3-5% of species, expresses in multiple formats, and involves flexible neurobiological accommodations to ecological conditions and active caregiving. Here, we discuss father contribution to resilience across development. Our model proposes three tenets of resilience - plasticity, sociality, and meaning - and discussion focuses on father-specific contributions to each tenet at different developmental stages; newborn, infant, preschooler, child, and adolescent. Father's style of high arousal, energetic physicality, guided participation in daily skills, joint adventure, and conflict resolution promotes children's flexible approach and social competence within intimate bonds and social groups. By expanding children's interests, sharpening cognitions, tuning affect regulation, encouraging exploration, and accompanying the search for identity, fathers support the sense of meaning, enhancing the human-specific dimension of resilience. We end by highlighting pitfalls to paternal contribution, including absence, abuse, rigidity, expectations, and gender typing, and the need to formulate novel theories to accommodate the "involved dad."

Association between parental behaviors and structural plasticity in the brain of male rodents

In recent decades, human fathers across the globe have shown a substantial increase in their engagement in paternal caregiving behaviors. Despite the growing interest, the precise neurobiological mechanisms underlying caregiving behaviors in males remain unclear. Neurobiological studies conducted on rodents have advanced our understanding of the molecular, cellular, and circuit-level mechanisms. Typically, sexually naïve males exhibit aggression toward offspring, while fathers display parental behaviors. This drastic behavioral plasticity may be associated with changes in connections among specific regions or cell types. Recent studies have begun to describe this structural plasticity by comparing neural connections before and after fatherhood. In this Perspective, we summarize the findings from four well-studied rodent species, namely prairie voles, California mice, laboratory rats, and laboratory mice, with a view toward integrating past and current progress. We then review recent advances in the understanding of structural plasticity for parental behaviors. Finally, we discuss remaining questions that require further exploration to gain a deeper understanding of the neural mechanisms underlying paternal behaviors in males, including their possible implications for the human brain.

Compensatory enhancement of paternal care in maternally neglected mice family

Parental care strategies, ranging from biparental to uniparental, evolve based on factors affecting sexual conflict over care. Plasticity in how parents respond to reduction in each other's care effort is thus proposed to be important in the evolution of parental care behaviors. Models predict that 'obligate' biparental care is stable when a parent responds to reduced partner effort with 'partial' compensation, trading-off current and future reproduction. A meta-analysis of experimental studies on biparental birds also revealed partial compensation, supporting coevolution of parental care type and plasticity pattern. However, few studies have addressed this issue across different taxa and different parental care types. In laboratory mice, a female-biased 'facultative' biparental species, fathers paired with a competent mother rarely provide care. We show that, when mated with a pup-neglecting mutant mother, fathers increased care effort to 'fully' compensate for the lost maternal care in both pup survival rate and total care amount. Pup retrieval latency was significantly shorter, and neural activity in relevant brain regions twice as high, suggesting enhanced motivation. This study with mice not only opens a road to explore the neural correlates of paternal plasticity but will also help understand how behavioral plasticity contributes to adaptive evolution of parental care behaviors.

Parental Narratives of Bonding and Relational Experiences with Preterm Infants Born at 23 to 24 Weeks-A Qualitative Descriptive Study

(1) Background. The birth of an infant at 23 to 24 weeks poses a significant challenge to healthy parent-infant bonding because of the high risk of infant loss and the prolonged separation. The aim of this study was to retrospectively explore the narratives of parents with children born at 23-24 weeks about their bonding formation and relational experiences. (2) Methods. This was a qualitative descriptive study conducted with Finnish parents of children born at 23 or 24 weeks of gestation. Twenty-nine mothers and eight fathers were retrospectively interviewed using a semi-structured interview about the bonding process with their infant during the period in the neonatal intensive care unit (NICU) and their later parent-child relationship. Parents' narratives were deductively analysed according to a framework previously developed for studying parental bonding. (3) Results. Our results showed that several parents described the bonding process as natural or even easy despite the traumatic start to parenthood. Support from NICU staff and providing opportunities for participation in infant care and parent-infant physical closeness were reported to enhance the bonding process. Our study identified earlier parenting experience as a new element supporting bonding. (4) Conclusions. According to our results, essential elements enhancing parent-infant bonding in NICU settings seem to be supporting parents psychologically, promoting parent-infant closeness, and encouraging parental participation in the infants' care, even with the most immature infants.

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.

Neural activation to infant cry among Latina and non-Latina White mothers

Cultural neuroscience is an emerging framework positing that culture (for example, values, beliefs, practices, and modes of emotional expression) critically informs socialization goals and desired behaviors, which are perhaps accompanied by differential patterns of brain activation. Using fMRI, the current study examines brain activation to infant cry stimuli and matched white noise among 50 first-time biological mothers identifying as Latina or White in the United States. Results showed that brain activation to infant cries in the right posterior insula, left cerebellum, and left auditory were higher for White mothers compared to Latina mothers, p's < .05. White mothers showed greater activation to cry sounds compared to white noise in the right dorsolateral prefrontal cortex, left somatosensory, right and left premotor cortices, p's < .05, whereas Latina mothers did not. These brain regions are involved in motor planning, movement, sensory processing, and social information processing. It is important to note that mothers in the two groups did not show differences in stress and behavioral parenting measures. Therefore, Latina and White mothers differentially recruiting brain regions related to infant parenting behaviors indicates the potential role of cultural context in shaping patterns of neural activation. Our exploratory analysis suggests that this difference might be due to greater pre-parenting exposure among Latina mothers to children compared to White mothers. Taken together, although our data did not completely explain the differences in brain activation between groups, findings suggest potential culture-related influences in brain activation occurring in the postpartum period.

Development of the Paternal Brain in Humans throughout Pregnancy

Previous studies have demonstrated that paternal caregiving behaviors are reliant on neural pathways similar to those supporting maternal care. Interestingly, a greater variability exists in parental phenotypes in men than in women among individuals and mammalian species. However, less is known about when or how such variability emerges in men. We investigated the longitudinal changes in the neural, hormonal, and psychological bases of expression of paternal caregiving in humans throughout pregnancy and the first 4 months of the postnatal period. We measured oxytocin and testosterone, paternity-related psychological traits, and neural response to infant-interaction videos using fMRI in first-time fathers and childless men at three time points (early to mid-pregnancy, late pregnancy, and postnatal). We found that paternal-specific brain activity in prefrontal areas distinctly develops during middle-to-late pregnancy and is enhanced in the postnatal period. In addition, among fathers, the timing of the development of prefrontal brain activity was associated with specific parenting phenotypes.

A Family Systems Perspective on Attachment Security and Dependency to Mother and Father in Preschool: Differential and Reciprocal Effects on Children's Emotional and Behavioral Problems

Attachment security and dependency play a decisive role for children's mental health. From a family systems perspective, reciprocal effects of dyadic attachment to each parent within the same family on child symptomatology may well offer additional insights in developmental processes as parents and children influence each other consistently. This study examined the influence of child-mother as well as child-father attachment security and dependency on maternal, paternal, and observed ratings of children's emotional and behavioral problems. A total of 124 families with preschool children participated in this study. Attachment security, dependency, and symptomatology of the children were independently observed during home visits. Furthermore, mothers and fathers rated child symptoms. Results revealed promotive effects of attachment security to both parents on observed child symptoms. Furthermore, we found a significant actor effect of child-mother attachment security, as well as a significant partner effect of child-father dependency on maternal ratings of child symptomatology. Attachment security to both parents is promotive for child mental health. The family systems perspective clarifies the meaning of child-father relationships for maternal perception of the own child.

A Scoping Study of Parents With a History of Childhood Sexual Abuse and a Theoretical Framework for Future Research

Transitioning to a parenting role is a complex psychological process that can be stressful for a parent with a history of childhood sexual abuse (CSA). Over the past decade, important advances have been made in identifying the effects of childhood trauma on parents' relationships with their children. This article presents a new theoretical framework that emerged from a scoping study of parenting experiences among adults who experienced CSA. The methods of Arksey and O'Malley were used to conduct the scoping study, and the guidelines for theory construction and model building developed by Jaccard and Jacoby were adopted. Only peer-reviewed published journal articles in English that studied exclusively CSA and its effects on parenting among individuals aged 18 years or older were included. Three resources for collecting data were used: (1) internet databases including PsycINFO and PubMed, (2) reference lists of review articles, and (3) the citation index functionality of Google Scholar for review articles. Forty-six articles were included in the scoping study. These studies mainly focused on mothers and their relationships with their children. No articles considered the age(s) at which parents experienced CSA and potential effects on parenting outcomes. In addition, there is limited knowledge about fathers with a history of CSA and their relationship with their children. The development of a theoretical framework designed through a methodologically driven identification of gaps in the body of knowledge provides a foundation for future research in this area.

Anomalous cerebral morphology of pregnant women with cleft fetuses

Objective

Pregnancy leads to long-lasting changes in brain structure for healthy women; however, little is known regarding alterations in the cortical features of pregnant women with malformed fetuses. Isolated clefts of the lip and/or palate (ICL/P) are the most common congenital anomaly in the craniofacial region, which is highly gene-associated. We speculated that pregnant women carrying fetuses with ICL/P may have associated risk genes and specific brain changes during pregnancy.

Methods

In this study, we investigated T1-weighted brain magnetic resonance imaging data from 48 pregnant women: 24 women carrying fetuses with ICL/P (ICL/P group) and 24 women carrying normal fetuses (normal controls), then explored intergroup differences in gray matter volume (GMV), cortical thickness (CT) and cortical complexity (gyrification).

Results

Compared with controls, the ICL/P group had decreased total intracranial volume (TIV) than normal controls; besides, they exhibited increased GMV in the left cuneus, decreased GMV in the right superior temporal gyrus; increased CT in the left precuneus and left superior parietal gyrus, decreased CT involving parsopercularis, fusiform, middle temporal in the left hemisphere and supramarginal, precentral gyrus (PreCG) in the right hemisphere; increased gyrification in the left insula and PreCG, the left middle temporal, and the right supratemporal gyrus.

Conclusion

Pregnant women with ICL/P fetuses had brain morphology changes involving language, auditory, vision, and sensory cortex, which may be their special brain changes compared to normal pregnant women. This study may provide clues for the early detection of fetuses with ICL/P, and be vital for preconception and prenatal counseling with non-invasive methods.

First-time fathers show longitudinal gray matter cortical volume reductions: evidence from two international samples

Emerging evidence points to the transition to parenthood as a critical window for adult neural plasticity. Studying fathers offers a unique opportunity to explore how parenting experience can shape the human brain when pregnancy is not directly experienced. Yet very few studies have examined the neuroanatomic adaptations of men transitioning into fatherhood. The present study reports on an international collaboration between two laboratories, one in Spain and the other in California (United States), that have prospectively collected structural neuroimaging data in 20 expectant fathers before and after the birth of their first child. The Spanish sample also included a control group of 17 childless men. We tested whether the transition into fatherhood entailed anatomical changes in brain cortical volume, thickness, and area, and subcortical volumes. We found overlapping trends of cortical volume reductions within the default mode network and visual networks and preservation of subcortical structures across both samples of first-time fathers, which persisted after controlling for fathers' and children's age at the postnatal scan. This study provides convergent evidence for cortical structural changes in fathers, supporting the possibility that the transition to fatherhood may represent a meaningful window of experience-induced structural neuroplasticity in males.

Examining the Role of Socioeconomic Status and Maternal Sensitivity in Predicting Functional Brain Network Connectivity in 5-Month-Old Infants

Infancy is a sensitive period of human brain development that is plastically shaped by environmental factors. Both proximal factors, such as sensitive parenting, and distal factors, such as socioeconomic status (SES), are known predictors of individual differences in structural and functional brain systems across the lifespan, yet it is unclear how these familial and contextual factors work together to shape functional brain development during infancy, particularly during the first months of life. In the current study, we examined pre-registered hypotheses regarding the interplay between these factors to assess how maternal sensitivity, within the broader context of socioeconomic variation, relates to the development of functional connectivity in long-range cortical brain networks. Specifically, we measured resting-state functional connectivity in three cortical brain networks (fronto-parietal network, default mode network, homologous-interhemispheric connectivity) using functional near-infrared spectroscopy (fNIRS), and examined the associations between maternal sensitivity, SES, and functional connectivity in a sample of 5-month-old infants and their mothers (N = 50 dyads). Results showed that all three networks were detectable during a passive viewing task, and that maternal sensitivity was positively associated with functional connectivity in the default mode network, such that infants with more sensitive mothers exhibited enhanced functional connectivity in this network. Contrary to hypotheses, we did not observe any associations of SES with functional connectivity in the brain networks assessed in this study. This suggests that at 5 months of age, maternal sensitivity is an important proximal environmental factor associated with individual differences in functional connectivity in a long-range cortical brain network implicated in a host of emotional and social-cognitive brain processes.

The effects of oxytocin and vasopressin administration on fathers' neural responses to infant crying: A randomized controlled within-subject study

In a randomized double-blind within-subject control study we investigated the effects of oxytocin and vasopressin administration on neural reactivity to infant cry sounds in 70 first-time fathers in the first year of fatherhood. Additionally, we examined whether effects of oxytocin and vasopressin administration on neural reactivity were moderated by fathers' early childhood experiences. Neural reactivity to infant cry sounds (versus control sounds) was measured using functional magnetic resonance imaging (fMRI). Furthermore, participants reported on their childhood experiences of parental harsh discipline and parental love withdrawal. Whole brain analyses revealed no significant effect of vasopressin or oxytocin administration on neural activation in response to infant cry sounds. Region of interest analyses showed decreased amygdala activation in both the oxytocin condition and the vasopressin condition as compared to placebo. We found no moderating effects of fathers' early childhood experiences. Our findings suggest that oxytocin administration may decrease feelings of anxiety or aversion to a crying infant. Whether decreased amygdala activation after vasopressin administration might be explained by contextual factors (e.g., absence of high levels of threat, unfamiliarity of the infant) or represents an affiliative response to infant distress warrants further investigation. Findings of the present study showed that oxytocin and vasopressin are important hormones implicated in neural models of infant cry perception in fatherhood.

The early-life stress induced by oxytocin inhibition in p53 knockout mouse dams increases adulthood tumorigenesis in first and second generations

BACKGROUND

Early-life stress due to poor parental care has been suggested to increase cancer risk, though, so far, no experimental evidence established a link between defective parental behavior and spontaneous tumorigenesis in progeny. Essential maternal behavior is regulated, in particular, by the oxytocin (OT) hormonal circuit, which in turn responds to stimuli from the offspring and impinges on the central nervous systems.

METHODS

By providing L-368,899 OT receptor (OTR) inhibitor to lactating mothers, we set up a model of defective maternal care in p53 knockout mice.

RESULTS

The progeny of these dams showed, later in life, higher cortisol levels, shortened life span and increased tumorigenic potential of bone marrow cells (BMC). Notably, these phenotypes were transmitted to the following generation.

CONCLUSIONS

Therefore, the inhibition of OT function in mothers is a novel paradigm of early-life stress that is inherited across generations and increases cancer risk in tumor-prone mice.

Plasticity of neural connections underlying oxytocin-mediated parental behaviors of male mice

The adult brain can flexibly adapt behaviors to specific life-stage demands. For example, while sexually naive male mice are aggressive to the conspecific young, they start to provide caregiving to infants around the time when their own young are expected. How such behavioral plasticity is implemented at the level of neural connections remains poorly understood. Here, using viral-genetic approaches, we establish hypothalamic oxytocin neurons as the key regulators of the parental caregiving behaviors of male mice. We then use rabies-virus-mediated unbiased screening to identify excitatory neural connections originating from the lateral hypothalamus to the oxytocin neurons to be drastically strengthened when male mice become fathers. These connections are functionally relevant, as their activation suppresses pup-directed aggression in virgin males. These results demonstrate the life-stage associated, long-distance, and cell-type-specific plasticity of neural connections in the hypothalamus, the brain region that is classically assumed to be hard-wired.

Experience-Regulated Neuronal Signaling in Maternal Behavior

Maternal behavior is shaped and challenged by the changing developmental needs of offspring and a broad range of environmental factors, with evidence indicating that the maternal brain exhibits a high degree of plasticity. This plasticity is displayed within cellular and molecular systems, including both intra- and intercellular signaling processes as well as transcriptional profiles. This experience-associated plasticity may have significant overlap with the mechanisms controlling memory processes, in particular those that are activity-dependent. While a significant body of work has identified various molecules and intracellular processes regulating maternal care, the role of activity- and experience-dependent processes remains unclear. We discuss recent progress in studying activity-dependent changes occurring at the synapse, in the nucleus, and during the transport between these two structures in relation to maternal behavior. Several pre- and postsynaptic molecules as well as transcription factors have been found to be critical in these processes. This role reflects the principal importance of the molecular and cellular mechanisms of memory formation to maternal and other behavioral adaptations.

Individual differences in social attachment: A multi-disciplinary perspective

Social behavior varies across both individuals and species. Research to explain this variation falls under the purview of multiple disciplines, each with its own theoretical and empirical traditions. Integration of these disciplinary traditions is key to developing a holistic perspective. Here, we review research on the biology of social attachment, a phenomena in which individuals develop strong affective connections to one another. We provide a historical overview of research on social attachment from psychological, ethological and neurobiological perspectives. As a case study, we describe work on pair-bonding in prairie voles, a socially monogamous rodent. This specific topic takes advantage of many biological perspectives and techniques to explain social bonds. Lastly, we conclude with an overview of multi-dimensional conceptual frameworks that can be used to explain social phenomena, and we propose a new framework for research on individual variation in attachment behavior. These conceptual frameworks originate from philosophy, physics, ethology, cognitive science and neuroscience. The application and synthesis of such frameworks offers a rich opportunity to advance understanding of social behavior and its mechanisms.

The Neural Basis of Human Fatherhood: A Unique Biocultural Perspective on Plasticity of Brain and Behavior

With the growing involvement of fathers in childrearing and the application of neuroscientific tools to research on parenting, there is a need to understand how a father's brain and neurohormonal systems accommodate the transition to parenthood and how such neurobiological changes impact children's mental health, sociality, and family functioning. In this paper, we present a theoretical model on the human father's brain and the neural adaptations that take place when fathers assume an involved role. The neurobiology of fatherhood shows great variability across individuals, societies, and cultures and is shaped to a great extent by bottom-up caregiving experiences and the amount of childrearing responsibilities. Mechanisms of mother-father coparental brain coordination and hormonal correlates of paternal behavior are detailed. Adaptations in the father's brain during pregnancy and across the postpartum year carry long-term implications for children's emotion regulation, stress management, and symptom formation. We propose a new conceptual model of HEALthy Father Brain that describes how a father's brain serves as a source of resilience in the context of family adversity and its capacity to "heal", protect, and foster social brain maturation and functionality in family members via paternal sensitivity, attunement, and support, which, in turn, promote child development and healthy family functioning. Father's brain provides a unique model on neural plasticity as sustained by committed acts of caregiving, thereby affording a novel perspective on the brain basis of human affiliation.

Less can be more: Fine tuning the maternal brain

PAWLUSKI, J.L., Hoekzema, E., Leuner, B., and Lonstein, J.S. Less can be more: Fine tuning the maternal brain. NEUROSCI BIOBEHAV REV (129) XXX-XXX, 2022. Plasticity in the female brain across the lifespan has recently become a growing field of scientific inquiry. This has led to the understanding that the transition to motherhood is marked by some of the most significant changes in brain plasticity in the adult female brain. Perhaps unexpectedly, plasticity occurring in the maternal brain often involves a decrease in brain volume, neurogenesis and glial cell density that presumably optimizes caregiving and other postpartum behaviors. This review summarizes what we know of the 'fine-tuning' of the female brain that accompanies motherhood and highlights the implications of these changes for maternal neurobehavioral health. The first part of the review summarizes structural and functional brain changes in humans during pregnancy and postpartum period with the remainder of the review focusing on neural and glial plasticity during the peripartum period in animal models. The aim of this review is to provide a clear understanding of when 'less is more' in maternal brain plasticity and where future research can focus to improve our understanding of the unique brain plasticity occurring during matrescence.

Early Life Adversity and Males: Biology, Behavior, and Implications for Fathers' Parenting

Fathers have an important and unique influence on child development, but influences on fathers' parenting have been vastly understudied in the scientific literature. In particular, very little empirical research exists on the effects of early life adversity (ELA; e.g. childhood maltreatment, parental separation) on later parenting among fathers. In this review, we draw from both the human and non-human animal literature to examine the effects of ELA, specifically among males, in the following areas: 1) neurobiology and neurocognitive functioning, 2) hormones and hormone receptors, 3) gene-environment interactions and epigenetics, and 4) behavior and development. Based on these findings, we present a conceptual model to describe the biological and behavioral pathways through which exposure to ELA may influence parenting among males, with a goal of guiding future research and intervention development in this area. Empirical studies are needed to improve understanding of the relationship between ELA and father's parenting, inform the development of paternal and biparental interventions, and prevent intergenerational transmission of ELA.

Acute inhibition of dopamine β-hydroxylase attenuates behavioral responses to pups in adult virgin California mice (Peromyscus californicus)

In biparental species, in which both parents care for their offspring, the neural and endocrine mediators of paternal behavior appear to overlap substantially with those underlying maternal behavior. Little is known, however, about the roles of classical neurotransmitters, such as norepinephrine (NE), in paternal care and whether they resemble those in maternal care. We tested the hypothesis that NE facilitates the initiation of nurturant behavior toward pups in virgin male and female California mice (Peromyscus californicus), a biparental rodent. Virtually all parents in this species are attracted to familiar and unfamiliar pups, while virgins either attack, avoid, or nurture pups, suggesting that the neurochemical control of pup-related behavior changes as mice transition into parenthood. We injected virgin males and females with nepicastat, a selective dopamine β-hydroxylase inhibitor that blocks NE synthesis (75 mg/kg, i.p.), or vehicle 2 h before exposing them to a novel pup, estrous female (males only), or pup-sized novel object for 60 min. Nepicastat significantly reduced the number of males and females that approached the pup and that displayed parental behavior. In contrast, nepicastat did not alter virgins' interactions with an estrous female or a novel object, suggesting that nepicastat-induced inhibition of interactions with pups was not mediated by changes in generalized neophobia, arousal, or activity. Nepicastat also significantly reduced NE levels in the amygdala and prefrontal cortex and increased the ratio of dopamine to NE in the hypothalamus. Our results suggest that NE may facilitate the initiation of parental behavior in male and female California mice.

Is Brain-Derived Neurotropic Factor Methylation Involved in the Association Between Prenatal Stress and Maternal Postnatal Anxiety During the COVID-19 Pandemic?

BACKGROUND

The COVID-19 pandemic is a collective trauma that may expose susceptible individuals to high levels of stress. Pregnant women represent a high-risk population, considering that pregnancy is a period of heightened neuroplasticity and susceptibility to stress through epigenetic mechanisms. Previous studies showed that the methylation status of the BDNF gene is linked with prenatal stress exposure. The goals of this study were (a) to assess the association between pandemic-related stress and postnatal anxiety and (b) to investigate the potential role of maternal BDNF methylation as a significant mediator of this association.

METHODS

In the present study, we report data on the association among pandemic-related stress during pregnancy, maternal BDNF methylation, and postnatal anxiety symptoms. Pandemic-related stress and postnatal anxiety were assessed through self-report instruments. BDNF methylation was estimated in 11 CpG sites in DNA from mothers' buccal cells. Complete data were available from 108 mothers.

RESULTS

Results showed that pandemic-related stress was associated with an increased risk of postnatal anxiety, r = 0.20, p < 0.05. CpG-specific BDNF methylation was significantly associated with both prenatal pandemic-related stress, r = 0.21, p < 0.05, and postnatal maternal anxious symptoms, r = 0.25, p = 0.01. Moreover, a complete mediation by the BDNF CpG6 methylation emerged between pandemic-related stress during pregnancy and postnatal maternal anxiety, ACME = 0.66, p < 0.05.

CONCLUSION

These findings suggest that BDNF epigenetic regulation by pandemic-related stress might contribute to increase the risk of anxiety in mothers. Policymakers should prioritize the promotion of health and wellbeing in pregnant women and mothers during the present healthcare emergency.

The neural correlates of grandmaternal caregiving

In many societies, grandmothers are important caregivers, and grandmaternal investment is often associated with improved grandchild well-being. Here, we present, to our knowledge, the first study to examine grandmaternal brain function. We recruited 50 grandmothers with at least one biological grandchild between 3 and 12 years old. Brain function was measured with functional magnetic resonance imaging as grandmothers viewed pictures of their grandchild, an unknown child, the same-sex parent of the grandchild, and an unknown adult. Grandmothers also completed questionnaires to measure their degree of involvement with and attachment to their grandchild. After controlling for age and familiarity of stimuli, viewing grandchild pictures activated areas involved with emotional empathy (insula and secondary somatosensory cortex) and movement (motor cortex and supplementary motor area). Grandmothers who more strongly activated areas involved with cognitive empathy (temporo-parietal junction and dorsomedial prefrontal cortex) when viewing pictures of the grandchild desired greater involvement in caring for the grandchild. Finally, compared with results from an earlier study of fathers, grandmothers more strongly activated regions involved with emotional empathy (dorsal anterior cingulate cortex, insula and secondary somatosensory cortex), and motivation (nucleus accumbens, ventral pallidum and caudate nucleus). All in all, our findings suggest that emotional empathy may be a key component of grandmaternal responses to their grandchildren.

Hypothalamus volume in men: Investigating associations with paternal status, self-reported caregiving beliefs, and adult attachment style

Most studies on mammalian caregiving and attachment focused on the mother-child relationship, particularly in humans. Yet, changing societal roles of male caregivers have highlighted the necessity for research with fathers.We examined the volume of the hypothalamus, an important subcortical brain area for caregiving and attachment, in N = 50 fathering (child age 5-6 years) and N = 45 non-fathering men using a novel technique to identify the hypothalamus in 3T MRI. We furthermore employed three self-report measures to assess interindividual differences in adult attachment style across all men and caregiving beliefs in fathers.While we did not observe any significant difference in hypothalamus volume between fathers and non-fathers or associations between hypothalamus volume and self-reported adult attachment style across all men, self-reported caregiving beliefs were positively related to total hypothalamus volume in fathers. A follow-up analysis showed that fathers' self-reported belief that a father's role is important to child development was specifically related to tuberal hypothalamus volume, while self-reported enjoyment of spending time with the child was not associated with sub-regional hypothalamus volume.Together, these findings suggest that interindividual variability in self-reported caregiving beliefs in fathers is related to brain structure, warranting further research.

Nine Levels of Explanation : A Proposed Expansion of Tinbergen's Four-Level Framework for Understanding the Causes of Behavior

Tinbergen's classic "On Aims and Methods of Ethology" (Zeitschrift für Tierpsychologie, 20, 1963) proposed four levels of explanation of behavior, which he thought would soon apply to humans. This paper discusses the need for multilevel explanation; Huxley and Mayr's prior models, and others that followed; Tinbergen's differences with Lorenz on "the innate"; and Mayr's ultimate/proximate distinction. It synthesizes these approaches with nine levels of explanation in three categories: phylogeny, natural selection, and genomics (ultimate causes); maturation, sensitive period effects, and routine environmental effects (intermediate causes); and hormonal/metabolic processes, neural circuitry, and eliciting stimuli (proximate causes), as a respectful extension of Tinbergen's levels. The proposed classification supports and builds on Tinbergen's multilevel model and Mayr's ultimate/proximate continuum, adding intermediate causes in accord with Tinbergen's emphasis on ontogeny. It requires no modification of Standard Evolutionary Theory or The Modern Synthesis, but shows that much that critics claim was missing was in fact part of Neo-Darwinian theory (so named by J. Mark Baldwin in The American Naturalist in 1896) all along, notably reciprocal causation in ontogeny, niche construction, cultural evolution, and multilevel selection. Updates of classical examples in ethology are offered at each of the nine levels, including the neuroethological and genomic findings Tinbergen foresaw. Finally, human examples are supplied at each level, fulfilling his hope of human applications as part of the biology of behavior. This broad ethological framework empowers us to explain human behavior-eventually completely-and vindicates the idea of human nature, and of humans as a part of nature.

Love and peace across generations: Biobehavioral systems and global partnerships

Children's environments - especially relationships with caregivers - sculpt not only developing brains but also multiple bio-behavioral systems that influence long-term cognitive and socioemotional outcomes, including the ability to empathize with others and interact in prosocial and peaceful ways. This speaks to the importance of investing resources in effective and timely programs that work to enhance early childhood development (ECD) and, by extension, reach communities at-scale. Given the limited resources currently devoted to ECD services, and the devastating impact of COVID-19 on children and communities, there is a clear need to spur government leaders and policymakers to further invest in ECD and related issues including gender and racial equity. This essay offers concrete examples of scholarly paradigms and leadership efforts that focus on child development to build a peaceful, equitable, just, and sustainable world. As scholars and practitioners, we need to continue to design, implement, assess, and revise high-quality child development programs that generate much-needed evidence for policy and programmatic changes. We must also invest in global partnerships to foster the next generation of scholars, practitioners, and advocates dedicated to advance our understanding of the bio-behavioral systems that underlie love, sociality, and peace across generations. Especially where supported by structural interventions, ECD programs can help create more peaceful, just, and socially equitable societies.

Love and longevity: A Social Dependency Hypothesis

Mammals, including humans, are reliant for survival and reproduction on adaptations associated with sociality and physiological investment, which can be linked to interactions with their parents or other bonded adult conspecifics. A wide range of evidence in human and non-human mammal species links social behaviors and relationships - including those characterized by what humans call "love" - to positive health and longevity. In light of this evidence, we propose a Social Dependency Hypothesis of Longevity, suggesting that natural selection has favored longer and healthier adult lives in species or in individuals exhibiting enhanced caregiver responsibilities contributing to the success of the next generation. In highlighting cellular, physiological, and behavioral effects of mammalian reproductive hormones, we examine the specific hypothesis that the neuropeptide oxytocin links longevity to the benefits of parental investment and associated relationships. Oxytocin is a pleiotropic molecule with anti-oxidant and anti-inflammatory properties, capable of regulating the hypothalamic-pituitary-adrenal axis, the parasympathetic nervous system and other systems associated with the management of various challenges, including chronic diseases and therefore may be crucial to establishing the maximum longevity potential of a species or an individual.

The roots of paternal depression: Experienced and nonexperienced trauma or Folie a Deux?

The transition to fatherhood may be challenged with anxiety and trepidation. A high prevalence has been found for paternal depression and it is reactive to maternal depression. This review aims to address potential sources of paternal depression, which may have adverse consequences on child development. We describe through three hypotheses how fathers may be at risk of depression during the transition to fatherhood: (1) psychological (interacting with ecological systems); (2) brain functional∖structural changes; and (3) (epi)genomic. We propose that paternal stressful experiences during the transition to fatherhood may be the source for paternal depression through direct stressful paternal experiences or via (potential, currently debated) nonexperienced (by the father) epigenomic transgenerational transmission. On the other hand, we suggest that resilient fathers may undergo a transient dysphoric period affected by identifying with the newborn's vulnerability as well as with the mother's postpartum vulnerability resulting in "paternity blues." In accordance with recent views on paternal "heightened sensitivity" toward the infant, we propose that the identification of both parents with the vulnerability of the newborn creates a sensitive period of Folie a Deux (shared madness) which may be a healthy transient, albeit a quasi-pathological period, recruited by the orienting response of the newborn for survival.

A soft baby carrier intervention enhances amygdala responses to infant crying in fathers: A randomized controlled trial

New fathers may grow into their parental role through active involvement in childcare. Spending time in physical contact with the child may promote an adaptive transition to fatherhood. In this randomized controlled trial, we tested the effects of a baby carrier intervention on fathers' hormonal and neural functioning. Using functional magnetic resonance imaging (fMRI), we examined whether infant carrying affects neural reactivity to infant crying in first-time fathers, taking into account the role of the hormone oxytocin as a mediating mechanism and fathers' own childhood experiences as a potential moderating factor. Sixty first-time fathers (infant age M = 11.18 weeks, SD = 2.08) were randomly assigned to a baby carrier intervention group (n = 32 fathers) or a control group (n = 28 fathers). Fathers in the intervention group were instructed to use a baby carrier for three weeks, whereas fathers in the control group were instructed to use a baby seat. Before and after the intervention salivary oxytocin was measured and neural reactivity to infant crying was assessed using fMRI. Results showed that the infant carrier intervention increased amygdala reactivity to infant crying compared to the infant seat users. This effect was most pronounced in fathers with experiences of childhood abuse. The carrier intervention did not affect fathers' oxytocin levels. Our findings indicate that spending time in physical contact with the infant may promote attention to and accurate perception of infant signals, in particular in fathers with more adverse childhood experiences. Soft baby carriers may, therefore, facilitate an adaptive transition to fatherhood.