Developmental consequences and biological significance of mother-infant bonding

Hypothalamic Vasopressin Neurons Enable Maternal Thermoregulatory Behaviors

Newborns of many mammalian species are partial poikilotherms and require adult thermoregulatory care for survival. In mice, pup survival in cold and cool ambient temperature depends on the ability of adult caregivers to huddle pups and bring them into a high-quality nest. It is therefore essential that adult mice adjust parental care as a function of changes in ambient temperature. Here, we investigated how mouse maternal care adapts to a range of temperatures, from cold to warm. We show that changes in ambient temperature affect several individual and co-parenting maternal behaviors in both dams and virgin female mice, and modulate activity of vasopressin neurons. Furthermore, we establish that the effects of ambient temperature on both maternal care and the activity of vasopressin neurons depend in part on thermosensation, specifically on the TRPM8 sensor. Using trans-synaptic anterograde tracing and whole-brain activity mapping, we find that vasopressin neurons from the paraventricular hypothalamic nucleus connect synaptically with temperature-responsive brain structures implicated in maternal care. We then show that optogenetic activation of vasopressin projections to the central amygdala, a structure activated by cold ambient temperature, recapitulates the effects of cold on co-parenting behaviors. Our data provide a biological mechanism for maternal thermoregulatory behavior in mice with translational relevance to the reported association between ecosystem temperature fluctuations and variations in human child neglect cases.

Dairy goat doe-kid rearing systems: Farmers' motivations and a description of practices, benefits and drawbacks

In French dairy goat systems, kids are generally separated from their mother does shortly after birth. The main drivers of this practice are related to health-especially the prevention of the Caprine Arthritis Encephalitis Virus (CAEV) transmission-and economics. However, the separation of young ruminants from their does is being increasingly questioned by society and has raised concerns about the satisfaction of their behavioral needs. Some farmers choose to leave their female kids with their does. The aims of this study were to understand their motivations for leaving kids with their does, to describe how kids are reared in this case and how farmers perceive different aspects of the impacts of this practice. Individual semi-structured interviews were carried out with 40 farmers who had implemented the kids-with-does practice for at least one year. Compared with the national database describing the French population of dairy goat farmers, the characteristics of the interviewed farmers differed from those of the general population. They were younger and had done longer studies. Their farms were smaller, mainly with rare breeds and milk was mainly processed on-farm under an organic certification system. They chose to implement this practice for different reasons: ethical considerations, improving integration of kids within the herd, saving time and increasing comfort at work or improving the kids' growth, welfare, and health. The doe-kid rearing contact practices varied greatly between farms, with some kids staying with their does from a period of 45 d to never being separated; furthermore, some kids remained with their does all day, while others remained together part of the day or for a limited time, and daily contact evolved over time. Overall, farmers were satisfied as the benefits quoted were coherent with their motivations to implement this rearing practice. Most have decided to continue the practice, though usually with changes. However, as 40% of them had only 3 years or less of experience of doe-kid rearing, some had not sufficient hindsight into long-term issues such as the transmission of CAEV. It is crucial to tackle challenges associated with this practice, i.e., potentially wild kids, health issues, and economic consequences stemming from a reduction in marketable milk.

The concept analysis of parent-infant bonding during pregnancy and infancy: a systematic review and meta-synthesis

INTRODUCTION

Despite the emerging body of literature on mother-to-infant bonding and the associated variables, there are various definitions of bonding construct. Also, there is a lack of a comprehensive conceptual framework of antecedents and consequences of bonding that would guide empirical work.

OBJECTIVE

Aim of the study was to provide a systematic review and synthesis of concept analysis studies on maternal-foetal, mother-infant, or father-infant bonding.

METHOD

A systematic search was performed in PubMed, EBSCOHost (including PsycINFO), ProQuest, and CINAHL. In addition, a hand search was conducted. Papers were eligible for inclusion if they conducted concept analyses on mother or father to foetus/infant bonding. A qualitative meta-synthesis was applied to synthesise the findings.

RESULTS

Eight papers on concept analyses were eligible for inclusion. In meta-synthesis, six aspects of parent-to-(unborn) child bonding emerged, including direction, domain, process, timing, endurance, and parental gender. Defining attributes are (i) a close relationship, (ii) filled with positive parental affection, (iii) manifested during pregnancy as monitoring foetal development and behaviour and after childbirth in proximity and interaction. Antecedents, affecting factors, and consequences of the parent-child bonding have been summarised.

CONCLUSION

Parent-infant bonding refers to an emotional, behavioural, cognitive, and neurobiological tie of the parent to the (unborn) child, as a process from intention to have a child throughout infancy. This is a parental-driven process which can continue to evolve throughout child's and parent's life, characterised as enduring, committed, and engaged. Based on meta-synthesis, a conceptual structure of parent-infant bonding has been provided, which needs further empirical testing.

Cat behaviour in the secure base test: Comparison between owned and shelter animals

The aim of the present study was to compare affiliative behaviours of owned and shelter cats directed to human in a novel environment after a brief temporary absence of the person. A sample of 20 owned and 20 shelter animals were individually tested in a Secure Base Test, with three 2-min episodes: 1) cat accompanied by a person who sits on the floor inside a circle, 2) the person leaves and the animal is left alone, 3) the person returns, and sits inside the circle again. Three categories were used for coding videotapes of experimental sessions: (1) inside circle, (2) allo-rubbing and (3) tail up. Shelter animals showed more proximity maintenance and affiliative signs with a person than owned animals. Our findings suggested similarities between the secure base effect in cats and in human children: cats seek proximity and maintain contact with a person, displaying affiliative signs to the person, especially after being left alone frightened by an unfamiliar environment.

What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development

Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills.

Activity-dependent development of the body's touch receptors

We report a role for activity in the development of the primary sensory neurons that detect touch. Genetic deletion of Piezo2, the principal mechanosensitive ion channel in somatosensory neurons, caused profound changes in the formation of mechanosensory end organ structures and altered somatosensory neuron central targeting. Single cell RNA sequencing of Piezo2 conditional mutants revealed changes in gene expression in the sensory neurons activated by light mechanical forces, whereas other neuronal classes were less affected. To further test the role of activity in mechanosensory end organ development, we genetically deleted the voltage-gated sodium channel Nav1.6 (Scn8a) in somatosensory neurons throughout development and found that Scn8a mutants also have disrupted somatosensory neuron morphologies and altered electrophysiological responses to mechanical stimuli. Together, these findings indicate that mechanically evoked neuronal activity acts early in life to shape the maturation of the mechanosensory end organs that underlie our sense of gentle touch.

Effects of Parity and Postpartum Depression on Mother-Infant Bonding in the First Month Postpartum: A Retrospective Study

Objective This study aimed to examine the relationship between parity, postpartum depression (PPD), and mother-infant bonding (MIB) failure in the first month postpartum. Methods The study included 1,509 Japanese patients (748 primiparous and 761 multiparous). MIB was assessed using the Mother-to-Infant Bonding Scale Japanese version (MIBS-J), which was translated in 2012, and its subscales, including lack of affection (LA) and anger and rejection (AR). Postpartum depression (PPD) was assessed using the Japanese version of the Edinburgh Postnatal Depression Scale (EPDS) and its subscales, including anxiety (ANX), anhedonia (ANH), and depression (DEP). Multiple regression analyses using interaction terms were performed to examine the association of parity with the MIBS-J and EPDS. Results Parity was significantly associated with AR. ANX and ANH were strongly associated with LA, and ANX and DEP were strongly associated with AR. The interaction term "parity×EPDS total" was significantly associated with MIBS-J total, LA, and AR scores. Conclusions Primiparas and mothers with high ANX had more negative emotions toward their children during the first month postpartum, and mothers with high ANX or ANH had less interest in their children.

Interrelationships between cows, calves, and humans in cow-calf contact systems-An interview study among Norwegian dairy farmers

In recent years, the common dairy farming practice of early separation of dam and calf has received increased attention. Our aim was to explore how Norwegian dairy farmers with cow-calf contact (CCC) systems apply these systems in practice, and how they experience and perceive the interrelationships between cows and calves and humans within these systems. We conducted in-depth interviews with 17 farmers from 12 dairy farms and analyzed responses inductively, inspired by the grounded theory approach. The farmers in our study practiced their CCC systems differently from each other and had varying as well as common perceptions about these systems. Calves' intake of colostrum was not seen as a challenge, regardless of practice. The farmers generally perceived that any aggression shown by cows toward humans was merely an exhibition of cows' natural protective instinct. However, when the farmers had good relationships with their cows and the cows felt safe around them, the farmers could handle the calves and build good relationships with them as well. The farmers experienced the calves learning a lot from their dams. Most of the farmers' dairy housing systems were not adapted for CCC, and CCC systems could require modification in terms of placing greater emphasis on observing the animals and making adjustments in the barn and around milking. Some thought having CCC on pasture was the best and most natural, while others were reluctant to have CCC on pasture. The farmers encountered some challenges with stressed animals after later separation, but several had found methods to minimize stress. Generally, they had different opinions about workload, but agreed they spent less time on calf feeding. We found that these farmers were thriving with their CCC systems; they all described positive emotions around seeing cows and their calves together. Animal welfare and natural behavior were important to the farmers.

Interaction of the pre- and postnatal environment in the maternal immune activation model

Adverse influences during pregnancy are associated with a range of unfavorable outcomes for the developing offspring. Maternal psychosocial stress, exposure to infections and nutritional imbalances are known risk factors for neurodevelopmental derangements and according psychiatric and neurological manifestations later in offspring life. In this context, the maternal immune activation (MIA) model has been extensively used in preclinical research to study how stimulation of the maternal immune system during gestation derails the tightly coordinated sequence of fetal neurodevelopment. The ensuing consequence of MIA for offspring brain structure and function are majorly manifested in behavioral and cognitive abnormalities, phenotypically presenting during the periods of adolescence and adulthood. These observations have been interpreted within the framework of the "double-hit-hypothesis" suggesting that an elevated risk for neurodevelopmental disorders results from an individual being subjected to two adverse environmental influences at distinct periods of life, jointly leading to the emergence of pathology. The early postnatal period, during which the caregiving parent is the major determinant of the newborn´s environment, constitutes a window of vulnerability to external stimuli. Considering that MIA not only affects the developing fetus, but also impinges on the mother´s brain, which is in a state of heightened malleability during pregnancy, the impact of MIA on maternal brain function and behavior postpartum may importantly contribute to the detrimental consequences for her progeny. Here we review current information on the interaction between the prenatal and postnatal maternal environments in the modulation of offspring development and their relevance for the pathophysiology of the MIA model.

Oxytocin level among patients with opioid use disorder and its correlation with personality traits and perceived childhood trauma

Background

Personality traits and perceived childhood maltreatment are of the predictors of substance use disorder development. Many studies have discussed oxytocin effect on personality traits and its relation with childhood trauma and how both affect the addictive process. The main aim was to compare oxytocin level between patients with opioid use disorder and controls and the potential association of oxytocin level with the basic dimensions of personality traits and perceived childhood adverse experiences in patients group. Forty male patients with opioid use disorder and 40 healthy controls matched in age and gender were assessed and compared regarding serum oxytocin level by ELISA, personality traits using Temperament and character inventory - revised (TCI- R) scale, and childhood adverse events using childhood trauma questionnaire.

Results

A significant difference between the patient group and the control group regarding the serum oxytocin level was found. Negative correlation with p-value <0.05 between oxytocin level and each of novelty seeking, and harm avoidance, in addition to a positive correlation between oxytocin level and each of reward dependence, self-directedness, and cooperativeness items of (TCR-R), among cases were found. Cases did not show statistically significant difference in oxytocin level between different Childhood Trauma Questionnaire (CTQ) items.

Conclusions

The interaction between serum oxytocin levels, personality traits, and childhood trauma has to be considered in management with heroin-dependent patients as it plays a crucial role.

Mother and sibling interactions during the preweaning period influence myelination and impulse propagation of the sensory sural nerve in the adult rat

To investigate whether mother and sibling interactions during the preweaning period influence the histological and electrophysiological characteristics of the sensory sural nerve (SUn) in the adult rat, litters composed of 1, 3, 6, 9, and 12 male pups (P) were formed and the pups routinely weighed until postnatal day 60 (PND60). At PND9, 3P and 6P litters showed greater body weight than pups without siblings or from 9P or 12P litters, and such differences in weight were maintained until adulthood. Analysis of maternal licking at PND8 and 9 showed that pups from large litters received fewer licks than pups from small size litters. At PND60, SUn of rats from 6P and 9P litters had greater compound action potential (CAP) amplitude and a higher proportion of axons with large myelin thickness than nerves from rats of 1P, 3P, or 12P litters. SUn of heaviest rats from 9P and 12P litters had greater CAP area and myelination than the lightest rats from the same litters. We propose that a complex interplay of sensory, social, and nutritional factors arising from mother and littermate interactions during the preweaning period influence myelination and the propagation of action potentials in the SUn of adult rats.

Early-life maternal deprivation affects the mother-offspring relationship in domestic pigs, as well as the neuroendocrine development and coping behavior of piglets

Early-life adversity may have programming effects on the psychological and physiological development of offspring. Domestic pigs (Sus scrofa) are an excellent model species for studying these effects because of their many physiological similarities to humans. Piglets from 10 sows were subjected to daily 2-h maternal deprivation on postnatal days (PND) 2–15 alone (DA) or in a group of littermates (DG). Control piglets (C) from 10 sows stayed with their mothers. Mother-offspring interaction, milk oxytocin, and cortisol were analyzed. An open-field/novel-object (OF/NO) test was performed with piglets on PNDs 16 and 40. Plasma cortisol and immune parameters were determined on PND 5 and 16. Two piglets from each group and sow were sacrificed on PND 20 and stress-related gene expression in the limbic system and prefrontal cortex (PFC), as well as splenic lymphocyte proliferative abilities, were examined. The milk cortisol of sows increased during the first separation of mother and offspring on the second day of lactation, whereas milk oxytocin did not change. The increase in cortisol by the OF/NO test on PND 16 was greater in C piglets than in DA and DG ones. DA piglets showed less agitated behavior than DG and C piglets in the OF/NO test at PND 16, but appeared more fearful. On PND 40, DA piglets showed more arousal than DG and C piglets in the OF/NO test. Neither plasma IgA nor N/L ratios in blood nor mitogen-induced proliferation of spleen lymphocytes were affected by deprivation. We found a higher mRNA expression of CRHR1 in the hypothalamus and a higher expression of MR in the hippocampus in DA piglets than in DG ones. The expression of GR, MR, and CRHR1 genes in the PFC was reduced by maternal deprivation, however, the expression of arginine vasopressin and oxytocin receptors was not affected. Repeated maternal deprivation induces sustained effects on stress reactivity and behavior of domestic piglets. Some of these effects were buffered by the presence of littermates. In addition, we found sex-specific differences in behavior and gene expression.

Effects of neonatal rearing by different types of foster mother on the distribution of corticotropin-releasing factor neurons in the central amygdaloid nucleus in rats

The mother-child relationship of newborns plays an essential role in the development of the central nervous system, and an inadequate relationship, such as mother-child separation, can cause deficits of mental function in adulthood. However, insufficient research has examined the effects of foster mothers. We assigned some neonatal rats to one of two foster mothers: one that was lactating and feeding her first litter (FL group) and one that had one previous experience of childbirth and feeding but no current litter (FE group). Other pups were raised by their own mother (OM group) or subjected to maternal separation (MS group). Pups were placed with the foster mother (FL and FE groups) or separated from their mother (MS group) for 3 h/day on postnatal days 1-20. At age 6 weeks, each group was divided into two subgroups, one with 30 min of acute restraint stress loading (FL-R, FE-R, OM-R, and MS-R) and one without it (FL, FE, OM, and MS). Then, we compared the density of corticotropin-releasing factor-immunoreactive (CRF-ir) neurons in the central amygdaloid nucleus (CeA). The density of CRF-ir neurons in the CeA was significantly lower in the FL-R and MS-R subgroups than in the FL and MS subgroups, respectively. The results suggest that differences in care received during the neonatal period affect maturation of CRF neurons in the CeA and may have negative effects on the synthesis and release of CRF.

Changes in Stereotypies: Effects over Time and over Generations

Simple Summary

Herein, we propose that there should be discussion about the function and effects of stereotypies in relation to the time during which they are shown. In the first stages, stereotypies may help animals deal with challenges. However, behavior can potentially alter the brain, impairing its function due the absence of a diverse repertory, and change brain connections, neurophysiology and later neuroanatomy. The neuroanatomical changes in individuals showing stereotypies could be an effect rather than a cause of the stereotypy. As a consequence, studies showing different outcomes for animal welfare from stereotypy expression could be due to variation in a timeline of expression. Stereotypies are widely used as an animal welfare indicator, and their expression can tell us about psychological states. However, there are questions about the longer-term consequences if animals express stereotypies: do the stereotypies help in coping? During the prenatal period, stereotypic behavior expressed by the mother can change the phenotype of the offspring, especially regarding emotionality, one mechanism acting via methylation in the limbic system in the brain. Are individuals that show stereotypies for shorter or longer periods all better adjusted, and hence have better welfare, or is the later welfare of some worse than that of individuals that do not show the behavior?

Abstract

Stereotypies comprise a wide range of repeated and apparently functionless behaviors that develop in individuals whose neural condition or environment results in poor welfare. While stereotypies are an indicator of poor welfare at the time of occurrence, they may have various consequences. Environmental enrichment modifies causal factors and reduces the occurrence of stereotypies, providing evidence that stereotypies are an indicator of poor welfare. However, stereotypy occurrence and consequences change over time. Furthermore, there are complex direct and epigenetic effects when mother mammals that are kept in negative conditions do or do not show stereotypies. It is proposed that, when trying to deal with challenging situations, stereotypies might initially help animals to cope. After further time in the conditions, the performance of the stereotypy may impair brain function and change brain connections, neurophysiology and eventually neuroanatomy. It is possible that reported neuroanatomical changes are an effect of the stereotypy rather than a cause.

Advanced paternal age diversifies individual trajectories of vocalization patterns in neonatal mice

Infant crying is a communicative behavior impaired in neurodevelopmental disorders (NDDs). Because advanced paternal age is a risk factor for NDDs, we performed computational approaches to evaluate how paternal age affected vocal communication and body weight development in C57BL/6 mouse offspring from young and aged fathers. Analyses of ultrasonic vocalization (USV) consisting of syllables showed that advanced paternal age reduced the number and duration of syllables, altered the syllable composition, and caused lower body weight gain in pups. Pups born to young fathers had convergent vocal characteristics with a rich repertoire, whereas those born to aged fathers exhibited more divergent vocal patterns with limited repertoire. Additional analyses revealed that some pups from aged fathers displayed atypical USV trajectories. Thus, our study indicates that advanced paternal age has a significant effect on offspring's vocal development. Our computational analyses are effective in characterizing altered individual diversity.

Taurine: A Maternally Derived Nutrient Linking Mother and Offspring

Mammals can obtain taurine from food and synthesize it from sulfur-containing amino acids. Mammalian fetuses and infants have little ability to synthesize taurine. Therefore, they are dependent on taurine given from mothers either via the placenta or via breast milk. Many lines of evidence demonstrate that maternally derived taurine is essential for offspring development, shaping various traits in adults. Various environmental factors, including maternal obesity, preeclampsia, and undernutrition, can affect the efficacy of taurine transfer via either the placenta or breast milk. Thus, maternally derived taurine during the perinatal period can influence the offspring’s development and even determine health and disease later in life. In this review, I will discuss the biological function of taurine during development and the regulatory mechanisms of taurine transport from mother to offspring. I also refer to the possible environmental factors affecting taurine functions in mother-offspring bonding during perinatal periods. The possible functions of taurine as a determinant of gut microbiota and in the context of the Developmental Origins of Health and Disease (DOHaD) hypothesis will also be discussed.

Neuroendocrine Mechanisms of Social Bonds and Separation Stress in Rodents, Dogs, and Other Species

Mammalian species form unique bonds between mothers and infants. Maternal care, including suckling, is necessary for infant survival, and the mother and, sometimes, the father require a lot of effort in nurturing infants. An infant's probability of survival depends on the extent of the investment of care by the mother. In parallel, mothers must identify their offspring and invest only in those who possess their genes to achieve evolutionary benefits. Therefore, they need to recognize their offspring and show a strong preference for them. For this reason, bond formation between mothers and infants is important. The mother monitors her offspring's physical condition and stays close to them. The offspring also form strong bonds with their mothers. Therefore, a separation between the mother and infant causes severe stress for both parties. Although it was initially thought that such bonds between mother and infant are limited to the same species, we have also observed a similar phenomenon in the human-dog relationship. In this article, we discuss the neuroendocrine mechanisms that underlie bond formation and separation based on findings of neurobiological research in mice and the relationship between humans and dogs.

Early Pup Removal Leads to Social Dysfunction and Dopamine Deficit in Late Postpartum Rats: Prevention by Social Support

Offspring interaction is among the most highly motivated behaviors in maternal mammals and is mediated by mesolimbic dopamine (DA) system activation. Disruption or loss of significant social relationships is among the strongest individual predictors of affective dysregulation and depression onset in humans. However, little is known regarding the effects of disrupted mother–infant attachment (pup removal) in rat dams. Here, we tested the effects of permanent pup removal in rat dams, which were assigned to one of three groups on postpartum day (PD) 1: pups; pups removed, single-housed; or pups removed, co-housed with another dam who also had pups removed; and underwent a behavioral test battery during PD 21–23. In vivo electrophysiological recordings of ventral tegmental area (VTA) DA neurons were performed on PD 22 and 23 in a subset of animals. Pup removal did not impact sucrose consumption or anxiety-like behavior, but increased passive forced swim test (FST) coping responses. Pup-removal effects on social behavior and VTA activity were sensitive to social buffering: only single-housed dams exhibited reduced social motivation and decreased numbers of active DA neurons. Dams that had pups removed and were co-housed did not exhibit changes in social behavior or VTA function. Moreover, no changes in social behavior, FST coping, or VTA activity were found in socially isolated adult virgin females, indicating that effects observed in dams are specific to pup loss. This study showed that deprivation of species-expected social relationships (pups) during the postpartum precipitates an enduring negative affect state (enhanced passive coping, blunted social motivation) and attenuated VTA DA function in the dam, and that a subset of these effects is partially ameliorated through social buffering.

Perineuronal net degradation rescues CA2 plasticity in a mouse model of Rett syndrome

Perineuronal nets (PNNs), a specialized form of extracellular matrix, are abnormal in the brains of people with Rett syndrome (RTT). We previously reported that PNNs function to restrict synaptic plasticity in hippocampal area CA2, which is unusually resistant to long-term potentiation (LTP) and has been linked to social learning in mice. Here we report that PNNs appear elevated in area CA2 of the hippocampus of an individual with RTT and that PNNs develop precociously and remain elevated in area CA2 of a mouse model of RTT (Mecp2-null). Further, we provide evidence that LTP could be induced at CA2 synapses prior to PNN maturation (postnatal day 8-11) in wild-type mice and that this window of plasticity was prematurely restricted at CA2 synapses in Mecp2-null mice. Degrading PNNs in Mecp2-null hippocampus was sufficient to rescue the premature disruption of CA2 plasticity. We identified several molecular targets that were altered in the developing Mecp2-null hippocampus that may explain aberrant PNNs and CA2 plasticity, and we discovered that CA2 PNNs are negatively regulated by neuronal activity. Collectively, our findings demonstrate that CA2 PNN development is regulated by Mecp2 and identify a window of hippocampal plasticity that is disrupted in a mouse model of RTT.

A Pilot Study of the Effects of Human Intervention on Canine Group Movement Behavior

Dogs are the oldest domesticated animals. The process of domestication of dogs is still unclear; however, they have established themselves as human partners and are sometimes more cooperative with humans than their conspecifics. In this study, to determine the effect of affiliative human presence on group behavior in dogs, we conducted short-time trials analyzing dog group movements. There was a hierarchical relationship in which juvenile dogs were aware of adult dogs, and adult dogs were aware of human movements. We also found that the age of the juvenile dog and the characteristics of their mothers may affect the movement behavior of juvenile dogs.

Biological Functions of Rat Ultrasonic Vocalizations, Arousal Mechanisms, and Call Initiation

This review summarizes all reported and suspected functions of ultrasonic vocalizations in infant and adult rats. The review leads to the conclusion that all types of ultrasonic vocalizations subserving all functions are vocal expressions of emotional arousal initiated by the activity of the reticular core of the brainstem. The emotional arousal is dichotomic in nature and is initiated by two opposite-in-function ascending reticular systems that are separate from the cognitive reticular activating system. The mesolimbic cholinergic system initiates the aversive state of anxiety with concomitant emission of 22 kHz calls, while the mesolimbic dopaminergic system initiates the appetitive state of hedonia with concomitant emission of 50 kHz vocalizations. These two mutually exclusive arousal systems prepare the animal for two different behavioral outcomes. The transition from broadband infant isolation calls to the well-structured adult types of vocalizations is explained, and the social importance of adult rat vocal communication is emphasized. The association of 22 kHz and 50 kHz vocalizations with aversive and appetitive states, respectively, was utilized in numerous quantitatively measured preclinical models of physiological, psychological, neurological, neuropsychiatric, and neurodevelopmental investigations. The present review should help in understanding and the interpretation of these models in biomedical research.

Infants exposed to antibiotics after birth have altered recognition memory responses at one month of age

BACKGROUND

Neonatal exposure to antibiotics, in the absence of infection, results in abnormal learning and memory in animals and is linked to changes in gut microbes. The relevance of early-life antibiotic exposure to brain function in humans is not known.

METHODS

Recognition memory was assessed at 1 month of age in 15 term-born infants exposed to antibiotics (with negative cultures) and 57 unexposed infants using event-related potentials (ERPs). Linear regression analysis, adjusting for covariates, was employed to compare groups with respect to ERP features representing early stimulus processing (P2 amplitude) and discrimination between mother and stranger voices.

RESULTS

Infants exposed to antibiotics exhibited smaller P2 amplitudes for both voice conditions (p = 0.001), with greatest reductions observed for mother's voice in frontal and central scalp regions (p < 0.04). Infants exposed to antibiotics showed larger P2 amplitudes to stranger's as compared to mother's voice, a reversal of the typical response exhibited by unexposed infants. Abnormal ERP responses did not consistently correlate with increased inflammatory cytokines within the antibiotic-exposed group.

CONCLUSIONS

Otherwise healthy infants exposed to antibiotics soon after birth demonstrated altered auditory processing and recognition memory responses, supporting the possibility of a microbiota-gut-brain axis in humans during early life.

IMPACT

Infants exposed to antibiotics after birth demonstrate altered auditory processing and recognition memory responses at 1 month of age. Preclinical models support a role for gut microbiomes in modulating brain function and behavior, particularly in developing brains. This study is one of the first to explore the relevance of these findings for human infants. The findings of this study have implications for the management and follow-up of at-risk infants with exposure to gut-microbiome disrupting factors and lay foundation for future studies to further characterize the short- and long-term effects of gut microbiome perturbation on brain development.

The Influence of Oxytocin on Maternal Care in Lactating Dogs

In recent years, many studies on the role of oxytocin (OXT) in the onset of parental care, regulation of social bonding, and modulation of the emotional state have been published. However, its possible regulation of maternal behavior in lactating dogs has not been investigated yet. For this reason, the present study aimed at assessing potential correlations between salivary oxytocin and maternal behavior in 25 lactating Labrador Retriever dogs. Salivary concentrations of OXT (sOXT) were unrelated to the amount of maternal care except for a weak negative correlation with sniffing/poking behavior. Moreover, sOXT was positively correlated with the percentage of male puppies. Sniffing/poking behavior, in turn, was positively correlated with the duration of time the mothers spent out of the whelping box, while the number of male puppies showed a positive correlation with lateral nursing, a position known to provide puppies the easiest access to the milk. Taken together, these results suggest that sOXT may not be strongly associated with maternal care dynamics but could be correlated with sex-biased parental investment in dogs.

Activation of the medial preoptic area (MPOA) ameliorates loss of maternal behavior in a Shank2 mouse model for autism

Impairments in social relationships and awareness are features observed in autism spectrum disorders (ASDs). However, the underlying mechanisms remain poorly understood. Shank2 is a high‐confidence ASD candidate gene and localizes primarily to postsynaptic densities (PSDs) of excitatory synapses in the central nervous system (CNS). We show here that loss of Shank2 in mice leads to a lack of social attachment and bonding behavior towards pubs independent of hormonal, cognitive, or sensitive deficits. Shank2^−/− mice display functional changes in nuclei of the social attachment circuit that were most prominent in the medial preoptic area (MPOA) of the hypothalamus. Selective enhancement of MPOA activity by DREADD technology re‐established social bonding behavior in Shank2^−/− mice, providing evidence that the identified circuit might be crucial for explaining how social deficits in ASD can arise.

Vertical transmission of gut microbiota: Points of action of environmental factors influencing brain development

Environmental factors in early life interact with genetics to exert a long-lasting and broad influence on health and disease. There has been a marked growth in the number of environmental factors studied in association with neurodevelopmental disorders. Colonization of the gut microbiota in the offspring uses the maternal resident flora as a primary source of bacteria during perinatal periods. Several lines of evidence have shown that various environmental factors including the mode of delivery, exposure to antibiotics, infection, stress, diet, quality of breast milk, and type of infant-feeding during the perinatal periods can perturb the gut microbiota colonization in the offspring, finally leading to disturbances in brain development. This study proposes that the gut microbiota seeded primarily by maternal microbiota, and the postnatal colonization of the microbiota in the offspring can be critical action points of environmental factors when deciphering the mechanisms of actions of environmental factors in brain development. This research reviews the inheritance and colonization of the microbiota during early life and the potential actions of the environmental factors influencing brain development in the offspring by modulating the vertical transmission of gut microbiota.

Predictors of Parental Presence in the Neonatal Intensive Care Unit

BACKGROUND

Parental presence in the neonatal intensive care unit (NICU) may affect preterm infants' developmental outcomes. However, few studies have described predictors of parental presence in the NICU.

PURPOSE

To identify sociodemographic, clinical, environmental, and maternal psychological factors that predict parent presence in the NICU.

METHODS

Using a prospective cohort design, 66 preterm infants between 32 and 40 weeks' corrected gestational age were recruited at 2 level III NICUs in the United States. Data for length of parental presence were collected for 48 consecutive hours from daily visitation logs and medical records. A general linear model was estimated to identify significant predictors of parental presence.

RESULTS

Parental presence varied considerably, with a mean percentage of visitation time of 32.40%. The number of children at home (P = .003), presence of neurological comorbidity (P < .001), room type (P < .001), surgical history (P < .001), and perceived stressfulness of the NICU (P = .03) each had large main effects on parental presence, and room type and surgical history (P = .004) had a large interaction effect on parental presence. These predictors accounted for 65.8% of the variance in parental presence.

IMPLICATIONS FOR RESEARCH

Future research aimed at understanding predictors of parent presence is essential for developing interventions and designing NICUs that support parental presence.

IMPLICATIONS FOR PRACTICE

Understanding factors that contribute to parental presence may help healthcare providers identify infants at risk for low parental presence and thus be able to provide greater support to these infants and their families. As a result, this may help improve outcomes and attachment.

Intergenerational transmission of the effects of maternal exposure to childhood maltreatment on offspring obesity risk: A fetal programming perspective

Childhood obesity constitutes a major global public health challenge. A substantial body of evidence suggests that conditions and states experienced by the embryo/fetus in utero can result in structural and functional changes in cells, tissues, organ systems and homeostatic set points related to obesity. Furthermore, growing evidence suggests that maternal conditions and states experienced prior to conception, such as stress, obesity and metabolic dysfunction, may spill over into pregnancy and influence those key aspects of gestational biology that program offspring obesity risk. In this narrative review, we advance a novel hypothesis and life-span framework to propose that maternal exposure to childhood maltreatment may constitute an important and as-yet-underappreciated risk factor implicated in developmental programming of offspring obesity risk via the long-term psychological, biological and behavioral sequelae of childhood maltreatment exposure. In this context, our framework considers the key role of maternal-placental-fetal endocrine, immune and metabolic pathways and also other processes including epigenetics, oocyte mitochondrial biology, and the maternal and infant microbiomes. Finally, our paper discusses future research directions required to elucidate the nature and mechanisms of the intergenerational transmission of the effects of maternal childhood maltreatment on offspring obesity risk.

Post-weaning infant-to-mother bonding in nutritionally independent female mice

Infant-parent attachment is highly selective and continues beyond essential care in primates, most prominently in humans, and the quality of this attachment crucially determines cognitive and emotional development of the infant. Altricial rodent species such as mice (Mus musculus) display mutual recognition and communal nursing in wild and laboratory environments, but parental bonding beyond the nursing period has not been reported. We presently demonstrated that socially and nutritionally independent mice still prefer to interact selectively with their mother dam. Furthermore, we observed gender differences in the mother-infant relationship, and showed disruption of this relationship in haploinsufficient Nbea+/- mice, a putative autism model with neuroendocrine dysregulation. To our knowledge, this is the first observation of murine infant-to-mother bonding beyond the nursing period.

Ear, tail and skin lesions vary according to different production flows in a farrow-to-finish pig farm

Background

Pig performance and risk of disease are associated with production flow. Given the link between health and welfare, it is likely that animal welfare indicators are also associated with production flow. This study investigated the association between production flow and tail, ear and skin lesions on a farm with a purported ‘all-in/all-out’ policy. This was an observational study whereby pigs were managed according to routine farm practice. A total of 1,016 pigs born within 1 week from the same batch were followed through the production stages and the presence or absence of welfare indicators was recorded at 4, 7, 9, 12, 16 and 24 weeks of age. Three production flows were retrospectively identified: flow 1 = ‘normal’ pigs that advanced through the production stages together ‘on time’, flow 2 = pigs delayed from advancing from the 1^st to the 2^nd nursery stage by 1 week and flow 3 = pigs delayed from advancing through the production stages by > 1 week. A nested case control design was applied by matching pigs by sow parity, number of born alive and birth weight.

Results

The presence of ear lesions was 4.5 less likely in pigs in flow 2 and 2.9 times less likely in pigs in flow 3 (P < 0.001) compared to pigs in flow 1. Pigs in flow 3 were 2.2 more likely to have tail and 1.6 times more likely to have ear lesions (P < 0.001) compared to pigs in flow 2. Pigs in flow 2 were less likely to have tail lesions compared with pigs in flow 1 (P < 0.05). Differences between production flows for the risk of skin lesions varied according to age (P < 0.05).

Conclusion

All production flows were associated with a high risk of lesions which raises concerns for pig welfare. However, risks for ear, tail and skin lesions varied according to each production flow likely due to the specific management practices inherent to each flow. Results from this study could be used to modify existing management practices, thus leading to improvements in animal welfare and possibly performance in intensive pig systems.

Maternal mouth-to-mouth feeding behaviour in flower-visiting bats, but no experimental evidence for transmitted dietary preferences

In addition to breast milk, several mammals feed their offspring with primary food items. This provisioning can offer both energetic and informational benefits: young might use parentally provided food as a source of nutrients, but also as a valuable option to socially learn about adults' food. For bats, there are only very few and partially anecdotal reports of adults feeding their pups with primary food, and there is also a lack of information about social learning processes during ontogeny. In the present study, we provide experimental evidence that lactating flower-visiting bats (Glossophaga soricina) provide regurgitated nectar via mouth-to-mouth feeding behaviour to their pups. After licking at their mothers' slightly opened mouth, pups defecated a marker substance that was exclusively available in the mothers' nectar diet. We additionally investigated associated informational benefits by testing for a social transmission of dietary preferences. We experimentally induced a dietary preference for specifically flavoured nectars to mothers with non-volant pups. Subsequently, after pups became volant, we tested their dietary preferences in a choice experiment. However, we found no experimental evidence that pups adopted the preferences of their mothers.

Oxytocin Receptor Binding Sites in the Periphery of the Neonatal Prairie Vole

The oxytocin receptor (OXTR) has been observed in the periphery of neonatal C57BL/6J mice (Mus musculus), including facial regions and the anogenital area. In those studies, ligand specificity was confirmed with a congenital OXTR knockout mouse as well as competitive binding techniques. The aim of this study was to determine if OXTR is present in the same peripheral sites in the neonatal prairie vole (Microtus ochrogaster) for cross-species comparisons. Receptor autoradiography was performed on 20 μm sagittal sections of whole postnatal day 0 (P0) male and female prairie voles using the ¹²⁵iodinated-ornithine vasotocin ([¹²⁵I]-OVTA) radioligand. A competition binding assay was used to assess the selectivity of [¹²⁵I]-OVTA for peripheral OXTR. Radioactive ligand (0.05 nM [¹²⁵I]-OVTA) was competed against concentrations of 0 and 1000 nM excess unlabeled oxytocin (OXT). Previously identified regions of significant OXTR ligand binding in the mouse were analyzed for comparison: rostral and lateral periodontium, olfactory epithelium, ciliary bodies of the eye, whisker pads, adrenal gland, and anogenital area. We also evaluated the liver and scapular brown adipose tissue, which displayed strong but non-specific signal on film in mice. While there were some areas that showed conserved OXTR ligand binding in the prairie vole (e.g., ciliary body of the eye and the anogenital area), areas showing OXTR ligand binding in the neonatal prairie vole were not identical to OXTR ligand binding in the periphery of the C57BL/6J neonatal mouse. Further, some of the regions measured in the prairie vole suggest sex differences in OXTR ligand binding. Collectively, as is well-established in the central nervous system, these data indicate that patterns of OXTR ligand binding in the infant periphery are species-specific.

Maternal Gastrointestinal Nematode Infection Up-regulates Expression of Genes Associated with Long-Term Potentiation in Perinatal Brains of Uninfected Developing Pups

Establishment of neural networks critical for memory and cognition begins during the perinatal period but studies on the impact of maternal infection are limited. Using a nematode parasite that remains in the maternal intestine, we tested our hypothesis that maternal infection during pregnancy and early lactation would alter perinatal brain gene expression, and that the anti-inflammatory nature of this parasite would promote synaptic plasticity and long-term potentiation. Brain gene expression was largely unaffected two days after birth, but in seven-day old pups, long-term potentiation and four related pathways essential for the development of synaptic plasticity, cognition and memory were up-regulated in pups of infected dams. Interestingly, our data suggest that a lowering of Th1 inflammatory processes may underscore the apparent beneficial impact of maternal intestinal infection on long-term potentiation.

Early weaning increases anxiety via brain-derived neurotrophic factor signaling in the mouse prefrontal cortex

Deprivation of maternal care during early development markedly affects emotional development, but the underlying neuromolecular mechanisms are not fully understood. In a mouse model of disrupted mother-infant relationship, early weaning causes long-term impacts on pups to exhibit increased corticosterone secretion, anxiety, and stress responses in their adulthood. Revealing the molecular mechanisms behind it would beneficial to ameliorating mental problems caused by abuse in childhood. We report that normalizing circulating corticosterone in early-weaned mice, either in adulthood or soon after weaning, ameliorated anxiety levels assessed in the plus maze test. Administering a glucocorticoid receptor antagonist into the prefrontal cortex (PFC) reversed the effects of early weaning, whereas administering corticosterone increased anxiety levels, suggesting that the PFC is corticosterone’s target brain region. In the PFCs of early-weaned mice, we observed prolonged reductions in the expression of brain-derived neurotrophic factor (BDNF) and associated mRNAs. Anxiety in early-weaned mice was ameliorated by pretreatment with BDNF or a BDNF receptor agonist. In summary, early weaning increased anxiety levels by modulating glucocorticoid and BDNF signaling in the PFC.

Maternal activity, anxiety, and protectiveness during moderate nutrient restriction in captive baboons (Papio sp.)

BACKGROUND

We hypothesized that maternal nutrient restriction (NR) would increase activity and behavioral indicators of anxiety (self-directed behaviors, SDBs) in captive baboons (Papio sp.) and result in more protective maternal styles.

METHODS

Our study included 19 adult female baboons. Seven females ate ad libitum (control group), and eight females ate 30% less (NR group) and were observed through pregnancy and lactation.

RESULTS

Control females engage in higher rates of SDB than NR females overall (P ≤ .018) and during the prenatal period (P ≤ .001) and engage in more aggressive behavior (P ≤ .033). Control females retrieved infants more than NR females during weeks 5-8 postpartum (P ≤ .019).

CONCLUSIONS

Lower SDB rates among prenatal NR females reduce energy expenditure and increase available resources for fetal development when nutritionally restricted. Higher infant retrieval rates by controls may indicate more infant independence rather than maternal style differences.

Influence of Maternal Care on Behavioural Development of Domestic Dogs (Canis Familiaris) Living in a Home Environment

Simple Summary

Maternal care in dogs and its impact on the behavioural development of puppies has become the subject of growing research interest. In order to determine the effects of maternal care on the behaviour of family dog puppies, maternal care during the first three weeks after birth was observed in 12 litters of puppies reared in a home environment (72 puppies). The behavioural responses of the puppies were assessed at two months of age, in an arena and an isolation test. In both tests, the amount of maternal care was found to be positively associated with some stress behaviours and, in the arena test, also with the puppies’ interest in an unfamiliar person who was present during the test. These behaviours are similar to those observed during the separation of other young mammals from an attachment figure with which they have a high quality of bond. Amount of maternal care was also found to be negatively associated with exploration and play. The difference in results between the present study and our previous study involving laboratory dogs reared in relative social isolation suggests that the developmental trajectory of puppies is influenced by a combination of maternal behaviour and social and physical environmental enrichment.

Abstract

Maternal care has been shown to affect the development of the brain, behaviour, social skills and emotional systems of the young of many mammalian species including dogs. The aim of the present study was to determine the effects of maternal care on the behavioural responses of family dog puppies towards environmental and social stimuli. In order to do this, maternal care (licking puppy’s ano-genital area, licking the puppy, nursing and mother-puppy contact) during the first three weeks after birth was assessed in 12 litters of domestic dog puppies reared in home environments (total = 72 puppies). The behavioural responses of puppies were assessed in an arena and an isolation test, which were performed when the puppies were two-month old. Data were analysed using principal components analysis and projection to latent structures regression. A systematic relationship was found between maternal care and behaviour in both tests. In the arena test, maternal care was found to be positively associated with approach to the stranger, attention oriented to the stranger, time spent near the enclosure, yawning, whining and yelping (R²Y = 0.613, p = 8.2 × 10⁻⁹). Amount of maternal care was negatively associated with the number of squares crossed and the time spent individually playing with the rope. In the isolation test, the amount of maternal care was positively associated with standing posture, paw lifting, and howling, and it was negatively associated with yawning, lying down and nose licking (R²Y = 0.507, p = 0.000626). These results suggest that the amount of maternal care received during early life influences the pattern of behavioural responses and coping strategies of puppies at two-months of age. On the basis of these findings it could be speculated that early maternal care contributes to adaption to the environment in which family puppies are developing, with particular regard to social relationships with people.

Differences in mother-to-infant bonding according to type of C-section: Elective versus unplanned

Aim To compare the mother-to-infant bond of mothers who gave birth by elective C-section versus urgent C-section in the first 48-72h of life and 10-12weeks after delivery.

METHODS

This is a cohort prospective study of women giving birth by C-section. 48-72h after delivery, sociodemographic variables were collected, Mother-to-Infant Bonding Scale and newborn's response to separation test were performed. 10-12weeks after delivery Mother-to-Infant Bonding Scale and questions about baby's feeding were completed.

RESULTS

A total of 116 dyads were recruited, 58 in each group. No significant differences between the two C-sections in bonding, newborn response to separation or type of feeding were observed at any time points. However, those dyads presenting with an abnormal bond at time 1 had more frequently an abnormal bond at time 2 (50% versus 8.1%, p=0.000).

CONCLUSIONS

No differences in mother-to-infant bond were found according to type of C-section.

Breastfeeding Challenges and the Preterm Mother-Infant Dyad: A Conceptual Model

Breastfeeding is an experience that only a mother and her infant(s) can share. Infants who can feed from the breast receive not only the best nutrition but also, due to the close physical contact between mother and child, it is the optimal nurturance they can receive from their mother. When breastfeeding is trouble free, maternal well-being is uniquely heightened. However, breastfeeding remains a challenge for many mother-infant dyads and more so for those whose infants are born prematurely. This article introduces a conceptual model of the breastfeeding challenges facing preterm mother-infant dyads. It distinguishes between a maternal caregiving and an infant growth/development components. Within the maternal component, two primary elements are considered, that is, maternal behavioral and nutritional care. The two primary elements within the infant component include infant non-nutritional and nutritional growth/development. It is proposed that an improved understanding of the factors associated with these four elements and how they interplay with each other within individual dyads will facilitate the identification of the breastfeeding challenges facing these mother-infant entities. Due to the intimate relationships existing between a mother and her infant(s), it is further advanced that breastfeeding studies would be optimized if mother-infant pairs are studied as one entity rather than mother and infant separately. It is proposed that this conceptual model will assist health professionals develop personalized breastfeeding management plans for individual preterm mother-infant dyads, while furthering the development of evidence-based interventions to optimize their breastfeeding experiences.

Increased oxytocin levels among abstinent heroin addicts: Association with aggressiveness, psychiatric symptoms and perceived childhood neglect

A disruption of the oxytocin system seems to affect a variety of brain functions including emotions, mood and social behavior possibly underlying severe social deficits and susceptibility for substance use and mental health disorders. Early life adversity, such as insecure attachment in childhood, has been suggested to influence oxytocin tone contributing to a condition of neurobiological vulnerability. Aim of the present study was to investigate oxytocin serum levels in abstinent heroin addicted patients, in comparison with healthy controls, and the possible correlation with co-occurring psychiatric symptoms, aggressiveness and perception of parental neglect. Eighteen (18) abstinent patients, affected by heroin use disorders, and 18 control subjects, who never used drugs or abused alcohol, were included in the study and submitted to 1) collection of a blood sample for oxytocin assay, 2) Symptoms Check List 90 for psychiatric symptoms evaluation 3) Buss Durkee Hostility Inventory to measure aggressiveness 4) Child Experience of Care and Abuse-Questionnaire to retrospectively test the perception of parental neglect. Heroin exposure extent and heroin dosages were also recorded. Oxytocin serum levels were unexpectedly significantly higher among abstinent patients affected by heroin use disorders and positively correlated with psychiatric symptoms, aggressiveness and mother neglect scores. No correlation was evidenced between oxytocin and heroin exposure extent or dosages. Our findings appear to contradict the simplistic view of oxytocin as a pro-social hormone and confirm previous evidence concerning the peptide levels direct association with aggressive behavior and mood disorders. Considering a more complex mechanism, oxytocin would increase the sensitivity to social salience cues related to contextual or inter-individual factors, promoting pro-sociality in "safe" conditions and, in contrast, inducing more defensive and "anti-social" emotions and behaviors when the social cues are interpreted as "unsafe". This latter condition is often characterizing the clinical history of addicted patients.

Mother-child adrenocortical synchrony; Moderation by dyadic relational behavior

Mother-child adrenocortical synchrony, the coupling of cortisol (CT) secretion in mother and child, has been associated with shared parent-child experiences and maladaptive familial contexts. Yet, few studies tested adrenocortical synchrony in diurnal CT patterns. Guided by the bio-behavioral synchrony model, we examined whether mother-child relational behavior and maternal psychopathology may moderate the degree of concordance between mother and child's diurnal CT. Ninety-seven mothers and their six-year old children participated in two groups; mothers diagnosed with major depression disorder (N=28) and non-depressed controls (N=69). Mother-child interactions were observed and coded for dyadic reciprocity and dyadic tension and diurnal cortisol was collected from mother and child over two consecutive weekend days. Concordance between maternal and child's diurnal CT was found, significant above and beyond time of measurement. Maternal depression, while associated with attenuated child diurnal CT variability, was unrelated to adrenocortical synchrony. Higher child diurnal CT production predicted a stronger linkage between maternal and child's diurnal CT, suggesting that greater child physiological stress is associated with increased susceptibility to the influences of maternal stress physiology. Mother-child reciprocity was related to lower adrenocortical synchrony. Findings suggest that higher adrenocortical synchrony is associated with greater physiological stress and less adaptive dyadic relational patterns. Results raise the possibility that diurnal adrenocortical synchrony taps a unique aspect of HPA-axis functioning whose role in the cross-generational transfer of stress physiology requires further research.

Oxytocin receptor binding sites in the periphery of the neonatal mouse

Oxytocin (OXT) is a pleiotropic regulator of physiology and behavior. An emerging body of evidence demonstrates a role for OXT in the transition to postnatal life of the infant. To identify potential sites of OXT action via the OXT receptor (OXTR) in the newborn mouse, we performed receptor autoradiography on 20 μm sagittal sections of whole postnatal day 0 male and female mice on a C57BL/6J background using the ¹²⁵iodinated ornithine vasotocin analog ([¹²⁵I]-OVTA) radioligand. A competitive binding assay on both wild-type (WT) and OXTR knockout (OXTR KO) tissue was used to assess the selectivity of [¹²⁵I]-OVTA for neonatal OXTR. Radioactive ligand (0.05 nM [¹²⁵I]-OVTA) was competed against concentrations of 0 nM, 10 nM, and 1000 nM excess unlabeled OXT. Autoradiographs demonstrated the high selectivity of the radioligand for infant peripheral OXTR. Specific ligand binding activity for OXTR was observed in the oronasal cavity, the eye, whisker pads, adrenal gland, and anogenital region in the neonatal OXTR WT mouse, but was absent in neonatal OXTR KO. Nonspecific binding was observed in areas with a high lipid content such as the scapular brown adipose tissue and the liver: in these regions, binding was present in both OXTR WT and KO mice, and could not be competed away with OXT in either WT or KO mice. Collectively, these data confirm novel OXT targets in the periphery of the neonate. These peripheral OXTR sites, coupled with the immaturity of the neonate’s own OXT system, suggest a role for exogenous OXT in modulating peripheral physiology and development.

Mutual mother-infant recognition in mice: The role of pup ultrasonic vocalizations

The importance of the mother-infant bond for the development of offspring health and sociality has been studied not only in primate species but also in rodent species. A social bond is defined as affiliative behaviors toward a specific partner. However, controversy remains concerning whether mouse pups can distinguish between their own mother and an alien mother, and whether mothers can differentiate their own pups from alien pups. In this study, we investigated whether mutual recognition exists between mother and infant in ICR mice. Furthermore, we studied pup ultrasonic vocalizations (USVs), which are emitted by pups when isolated from their mothers, to determine whether they constituted an individual signature used by the mother for pup recognition. We conducted a variety of two-choice tests and selective-retrieving tests. In a two-choice test for mother recognition by the pup, pups between the ages of 17 and 21days preferred their own mothers to alien mothers. In a two-choice test for pup recognition by its mother, the mothers located their own pups faster than alien pups at the beginning of the test, yet displayed similar retrieving activity for both their own and alien pups in the subsequent selective-retrieving test. Furthermore, after recording USVs from pups from subject and alien mothers, then playing them simultaneously, subject mothers displayed a preference for pup USVs emitted by their own pups. Overall, our findings support the existence of mother-infant bonding in mice and suggest that pup USVs contribute to pup recognition by mothers.

Assessment of psychometric properties of the Postpartum Bonding Questionnaire (PBQ) in Spanish mothers

The Postpartum Bonding Questionnaire (PBQ) was developed to assess mother-infant bonding disturbances in the postpartum period. The aim of this study was to examine the psychometric properties of the Spanish version of the PBQ in a sample of Spanish postpartum women. Eight hundred forty mothers were recruited in the postpartum visit (4-6 weeks after delivery): 513 from a gynecology unit (forming the general population sample) and 327 mothers from a perinatal psychiatry program (forming the clinical sample). All women were assessed by means of the Edinburgh Postnatal Depression Scale (EPDS) and the PBQ. Neither the original four-factor structure nor alternative structures (Reck et al. 2006; Wittkowski et al. 2010) were replicated by the confirmatory factor analyses. An exploratory factor analysis showed a four-factor solution. The Schmid-Leiman transformation found a general factor that accounted for 61% of the variance of the PBQ. Bonding impairment showed higher associations with depressive symptomatology in both samples. The Spanish version of the PBQ showed adequate psychometric properties for use with clinical and general populations of Spanish postpartum women. The results suggest that the PBQ could be summarized by a general factor and confirm the utility of the use of the total score for detecting bonding impairment.