The Neurobiology of Human Attachments

A context-dependent perspective to understand the relation between parent-child physiological synchrony and child socioemotional adjustment

Physiological synchrony is an important biological process during which parent-child interaction plays a significant role in shaping child socioemotional adjustment. The present study held a context-dependent perspective to examine the conditional association between parent-child physiological synchrony and child socioemotional adjustment (i.e., relationship quality with parents and child emotion regulation) under different (i.e., from highly unsupportive to highly supportive) emotional contexts. One hundred and fifty school-age Chinese children (Mage = 8.64 years, 63 girls) and their primary caregivers participated in this study. After attaching electrocardiogram (ECG) electrodes, parent-child dyads were instructed to complete a 4-minute conflict discussion task. Parent-child physiological synchrony was calculated based on the within-dyad association between parents' and children's respiratory sinus arrhythmia (RSA) levels across eight 30-second epochs. Parental emotional support, child relationship quality with parents, and child emotion regulation during the discussion task were coded by trained research assistants. Supporting our hypotheses, parental emotional support moderated the relations of parent-child RSA synchrony with both child relationship quality with parents and child emotion regulation. Furthermore, the Johnson-Neyman technique of moderation indicated that the associations between parent and child RSA synchrony and child socioemotional adjustment indicators shifted from negative to positive as the parental emotional support became increasingly high. Our findings suggest that parent-child physiological synchrony may not be inherently adaptive or maladaptive, highlighting the importance of understanding the function of parent-child physiological synchrony under specific contexts. RESEARCH HIGHLIGHTS: Physiological synchrony may not be inherently adaptive or maladaptive, and the meanings of parent-child physiological synchrony might be contingent on contextual factors. Parental emotional support moderated the relations between parent-child respiratory sinus arrhythmia (RSA) synchrony and child socioemotional adjustment indicators (i.e., child relationship quality with parents and child emotion regulation). More positive/less negative parent-child RSA synchrony was associated with better child socioemotional adjustment under a supportive emotional context, whereas with poorer child socioemotional adjustment under an unsupportive emotional context. These findings highlight the significance of considering the emotional context in physiological synchrony studies.

Sexual Synchrony During Partnered Sex

There is growing interest in understanding how sexual arousal unfolds between partners, and how this may change over the course of a relationship and in the face of sexual distress. To capture the variable, dynamic, and dyadic nature of sexual responding, this paper introduces the concept of sexual synchrony, defined as the temporal, reciprocal, and coordinated interchange between partners' subjective and genital sexual arousal. Sexual synchrony is a key mechanism for understanding how partners experience and adapt their sexual arousal responses as they evolve over time. Its relevance lies in examining the mechanisms that may disrupt and facilitate synchrony and exploring how it may contribute to sexual well-being by enabling partners to mutually regulate their sexual arousal within and across sexual interactions. The paper also discusses how sexual synchrony may evolve throughout relationship development and its potential role in sexual problems, offering valuable insights into improving sexual relationships. Suggestions are provided for future research, together with a discussion of the methodological and statistical issues involved when examining sexual dynamics. Understanding how partners jointly regulate their sexual responses allows the development of dyadic models of sexual arousal which will inform treatments for improving couples' (sexual) well-being. The study of sexual synchrony also exemplifies the importance of translational research that is relevant across disciplinary borders.

Reciprocal self-disclosure makes children feel more loved by their parents in the moment: A proof-of-concept experiment

Feeling loved by one's parents is critical for children's health and well-being. How can such feelings be fostered? A vital feature of loving interactions is reciprocal self-disclosure, where individuals disclose intimate information about themselves. In a proof-of-concept experiment, we examined whether encouraging reciprocal self-disclosure in parent-child dyads would make children feel more loved during the conversation. Participants were 218 children (ages 8-13, 50% girls, 94% Dutch) and one of their parents (ages 28-56, 62% women, 90% Dutch). Parent-child dyads received a list of 14 questions and took turns asking them each other for 9 min. Dyads were assigned randomly to engage in self-disclosure (questions invoking escalated intimacy) or small talk (questions invoking minimal intimacy). Before and after, children reported how loved they felt by their parent during the conversation. Self-disclosure made children feel more loved during the conversation than did small talk. Compared to small talk, self-disclosure did not instigate conversations that were lengthier or more positive; rather, it instigated conversations that were more emotionally charged (reflecting anger, anxiety, and sadness), social (discussing family and friends), reflective (creating insight), and meaningful (addressing deeply personal topics, including the passing of loved ones). The dyad's gender composition did not significantly moderate these effects. Our research suggests that reciprocal self-disclosure can make children feel more loved in the moment, uncovers linguistic signatures of reciprocal self-disclosure, and offers developmental scientists a tool to examine causal effects of reciprocal self-disclosure in parent-child dyads. Future work should examine long-term effects in everyday parent-child interactions. RESEARCH HIGHLIGHTS: How can parents make children feel more loved by them in the moment? We theorize that these feelings can be cultivated through reciprocal self-disclosure. In a proof-of-concept experiment, we examined effects of reciprocal self-disclosure versus small talk in 218 parent-child dyads, with children aged 8-13. Self-disclosure (vs. small talk) made children feel more loved during the conversation. Linguistically, self-disclosure instigated conversations that were more emotionally charged, social, reflective, and meaningful. This research provides an experimental method to study self-disclosure in parent-child dyads and suggests that self-disclosure can make children feel more loved in the moment.

Mechanisms of Social Attachment Between Children and Pet Dogs

An increasing body of evidence indicates that owning a pet dog is associated with improvements in child health and well-being. Importantly, the degree of the social bond between child and dog may mediate the beneficial outcomes of dog ownership. The formation of social bonds is an intrinsically dyadic, interactive process where each interactor's behavior influences the other's behavior. For this reason, it is critical to evaluate the biological mechanisms of attachment in both children and their pet dogs as a socially bonded pair. Here, we review the physical, mental, and emotional outcomes that are associated with pet dog ownership or interaction in children. We then discuss the evidence that suggests that the strength of a social bond between a child and their pet dog matters for maximizing the beneficial outcomes associated with pet dog ownership, such as possible stress-buffering effects. We review the existing literature on the neural and endocrinological mechanisms of social attachment for inter-species social bonds that form between human children and dogs, situating this emerging knowledge within the context of the mechanisms of intra-species bonds in mammals. Finally, we highlight the remaining open questions and point toward directions for future research.

Minds in movement: embodied cognition in the age of artificial intelligence

This theme issue brings together researchers from diverse fields to assess the current status and future prospects of embodied cognition in the age of generative artificial intelligence. In this introduction, we first clarify our view of embodiment as a potentially unifying concept in the study of cognition, characterizing this as a perspective that questions mind-body dualism and recognizes a profound continuity between sensorimotor action in the world and more abstract forms of cognition. We then consider how this unifying concept is developed and elaborated by the other contributions to this issue, identifying the following two key themes: (i) the role of language in cognition and its entanglement with the body and (ii) bodily mechanisms of interpersonal perception and alignment across the domains of social affiliation, teaching and learning. On balance, we consider that embodied approaches to the study of cognition, culture and evolution remain promising, but will require greater integration across disciplines to fully realize their potential. We conclude by suggesting that researchers will need to be ready and able to meet the various methodological, theoretical and practical challenges this will entail and remain open to encountering markedly different viewpoints about how and why embodiment matters. This article is the part of this theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Neural correlates of distress and comfort in individuals with avoidant, anxious and secure attachment style: an fMRI study

Despite a growing literature, experiments directly related to attachment are still needed. We explored brain processes involved in two aspects of attachment, distress and comfort. Seventy-eight healthy adult males with different attachment styles (secure, avoidant, and anxious) viewed distress, comfort, complicity-joy and neutral images (picture database BAPS-Adult) in an fMRI block design. ROIs from the modules described in the functional Neuro-Anatomical Model of Attachment (Long et al. 2020) were studied. Secure participants used more co- and self-regulation strategies and exhibited a higher activation of the reward network in distress and comfort viewing, than insecure participants. Avoidant participants showed the lower brain activations. Their approach and reward modules were the least activated in distress and comfort. Anxious participants presented both higher activations of the approach and aversion modules during complicity-joy. In addition, comfort and complicity-joy were processed differently according to attachment styles and should be differentiated among positive stimuli to disentangle attachment processes.

Disruption in cortisol synchrony and pair-dissolution in the serially monogamous convict cichlid (Amatitlania nigrofasciata)

Endocrine synchronization is a biological process often associated with social bonding. The mechanisms that mediate this process have been well studied in many vertebrate clades with evolved complex social behaviors. However, studies focusing on such processes in the less neurologically complex teleost clade are surprisingly lacking. In this study, we investigated the hypothesis that mated pairs of convict cichlids (Amatitlania nigrofasciata) perform cortisol synchronization and that the disruption of this might accompany pair-bond instability. Mated pairs were subjected to both behavioral and non-invasive waterborne hormonal assays to better understand the biological complexity of endocrine synchrony and its role in pair-bonding. Baseline cortisol assays indicated a positive correlation between male and female cortisol levels. Individuals that were subjected to a prolonged separation from their mate exhibited a negative correlation in cortisol synchrony after being reunited with their mate. Cortisol synchrony was disrupted, but pairs did not show a significant variance of intrapair aggression after initial pair reunion. However, more than half of the pairs that received the stressor exhibited significantly higher levels of intrapair aggression than their time matched controls approximately 1-7 days following this reunion, indicating pair-dissolution. Concurrently, pairs who underwent the stressor but maintained their bonds did not display an increase in intrapair aggression and also re-synchronized their cortisol levels. Not only does this study provide crucial insights in regard to the role of cortisol synchrony in serially monogamous systems, but it also suggests that the mechanisms that mediate the synchronization of endocrine through the formation of social bonds are more evolutionarily conserved than originally thought.

Sensitive infant care tunes a frontotemporal interbrain network in adolescence

Caregiving plays a critical role in children's cognitive, emotional, and psychological well-being. In the current longitudinal study, we investigated the enduring effects of early maternal behavior on processes of interbrain synchrony in adolescence. Mother-infant naturalistic interactions were filmed when infants were 3-4 months old and interactions were coded for maternal sensitivity and intrusiveness with the Coding Interactive Behavior Manual. In early adolescence (Mean = 12.30, SD = 1.25), mother-adolescent interbrain synchrony was measured using hyperscanning EEG during a naturalistic interaction of positive valence. Guided by previous hyperscanning studies, we focused on interbrain connections within the right frontotemporal interbrain network. Results indicate that maternal sensitivity in early infancy was longitudinally associated with neural synchrony in the right interbrain frontotemporal network. Post-hoc comparisons highlighted enhancement of mother-adolescent frontal-frontal connectivity, a connection that has been implicated in parent-child social communication. In contrast, maternal intrusiveness in infancy was linked with attenuation of interbrain synchrony in the right interbrain frontotemporal network. Sensitivity and intrusiveness are key maternal social orientations that have shown to be individually stable in the mother-child relationship from infancy to adulthood and foreshadow children's positive and negative social-emotional outcomes, respectively. Our findings are the first to demonstrate that these two maternal orientations play a role in enhancing or attenuating the child's interbrain frontotemporal network, which sustains social communication and affiliation. Results suggest that the reported long-term impact of maternal sensitivity and intrusiveness may relate, in part, to its effects on tuning the child's brain to sociality.

Parent emotional support alters the association between parent-child interbrain synchrony and interaction quality

Using functional near-infrared spectroscopy (fNIRS) hyperscanning methodology, this study investigated whether parent emotional support moderated the relation between parent-child interbrain synchrony and interaction quality (via behavioral observation and child-report), controlling for individual emotional distress. Eighty-eight parent-child dyads (96.6% Han ethnicity), including a school-age child between the ages of 6 and 11 (Mage = 8.07 years, SD = 1.16 years; 58.0% boys) and their parent (Mage = 39.03 years, SD = 3.54 years; 69.3% mothers), participated in a cooperative task during which brain activity was assessed. Cluster-based permutations indicated parent-child interbrain synchrony in the left and right temporoparietal junction (TPJ). Interbrain synchrony in the left TPJ positively related to parent-child interaction quality in the context of high parent emotional support, whereas the association was weaker and negative when parents demonstrated low emotional support. Findings suggest the emotional context of an interaction is critical when assessing interbrain synchrony.

Oxytocin receptor controls distinct components of pair bonding and development in prairie voles

Oxytocin receptor (Oxtr) signaling influences complex social behaviors in diverse species, including social monogamy in prairie voles. How Oxtr regulates specific components of social attachment behaviors and the neural mechanisms mediating them remains unknown. Here, we examine prairie voles lacking Oxtr and demonstrate that pair bonding comprises distinct behavioral modules: the preference for a bonded partner, and the rejection of novel potential mates. Our longitudinal study of social attachment shows that Oxtr sex-specifically influences early interactions between novel partners facilitating the formation of partner preference. Additionally, Oxtr suppresses promiscuity towards novel potential mates following pair bonding, contributing to rejection. Oxtr function regulates coordinated patterns of gene expression in regions implicated in attachment behaviors and regulates the expression of oxytocin in the paraventricular nucleus of the hypothalamus, a principal source of oxytocin. Thus, Oxtr controls genetically separable components of pair bonding behaviors and coordinates development of the neural substrates of attachment.

Constructing the "Family Personality": Can Family Functioning Be Linked to Parent-Child Interpersonal Neural Synchronization?

INTRODUCTION

Early child development occurs within an interactive environment, initially dominated by parents or caregivers, and is heavily influenced by the dynamics of this social context. The current study probed the neurobiology of "family personality", or family functioning, in the context of parent-child dyadic interaction using a two-person neuroimaging modality.

METHODS

One hundred and five parent-child dyads (child mean age 5 years 4 months) were recruited. Functional near-infrared spectroscopy (fNIRS) hyperscanning was employed to measure neural synchrony while dyads completed a mildly stressful interactive task. Family functioning was measured through the Family Adaptability and Cohesion Scale IV (FACES-IV).

RESULTS

Synchrony during stress was significantly greater than synchrony during both baseline and recovery conditions for all dyads. A significant interaction between neural synchrony in each task condition and familial balanced flexibility was found, such that higher levels of balanced flexibility were associated with greater changes in frontal cortex neural synchrony as dyads progressed through the three task conditions.

DISCUSSION

Parent-child dyads from families who display heightened levels of balanced flexibility are also more flexible in their engagement of neural synchrony when shifting between social conditions. This is one of the first studies to utilize a two-person imaging modality to explore the links between family functioning and interbrain synchrony between parents and their children.

On social health: history, conceptualization, and population patterning

We propose a psychologically-informed concept of social health to join physical and mental components in a more comprehensive assessment of human health. Although there is an extensive literature on the importance of social relationships to health, a theoretical framework is needed to coalesce this work into a codified conceptualisation of social health, defined here as adequate quantity and quality of relationships in a particular context to meet an individual's need for meaningful human connection. Informing this novel conceptualisation, we outline eight key propositions to guide future research and theory on social health, including five propositions focused on the conceptualisation of social health and three focused on its population patterning. The former five propositions include that social health is an outcome in its own right, that health interventions can have divergent effects on social versus physical and mental aspects of health, that social health has independent effects on quality of life, that it is a dynamic and contextual construct, and that it is embedded and encoded in the human body (and mind). The utility of the social health concept is further revealed in its significance for understanding and addressing population health concerns, such as health inequalities experienced by marginalised groups.

Cerebral Synchronization Between Mothers and Their Newborns During Breastfeeding

Introduction: Breastfeeding is a fundamental biological function in mammals, allowing the progeny to develop in a physiological way. A physical and emotional dialog between mothers and offspring during breastfeeding has been described as part of the attachment relationship, and a synchronicity between maternal and neonatal brains can be hypothesized. This study aimed to assess if neonatal and maternal cortical areas activated during breastfeeding are functionally synchronized since the second day of life. Materials and Methods: Twenty mothers and their term newborns were enrolled. Cortical activation during breastfeeding was identified by multichannel near-infrared spectroscopy, which detects changes in haemoglobin concentration from multiple cortical regions. Functional activity was simultaneously detected (hyperscanning) in mothers and newborns' frontal and motor/primary somatosensory cortical areas during the first 5 minutes of breastfeeding. Cluster analysis and Student's t test were used to detect oxygenated haemoglobin increase, as cortical activation estimate. Wavelet transform coherence (WTC) analysis was used to identify a possible synchronization between maternal and neonatal activated cortical regions. Results: Mothers showed an activation of the central motor/primary somatosensory cortex, above the sagittal fissure. In newborns, the bilateral frontal cortex was activated. WTC analysis revealed two different cyclical synchronizations between mothers and infants' activated cortical regions. Conclusions: Such evidence may reflect a very early common sharing of experiences, possibly associated with reciprocal dynamic motor adjustments, hormonal coregulation, and somatic stimulations and sensations. The observed cyclical neural synchronization, between the mother and her newborn's cortex during breastfeeding, may play an important role in promoting their bonding.

Synchrony within, synchrony without: establishing the link between interpersonal behavioural and brain-to-brain synchrony during role-play

Interpersonal synchrony is a crucial construct in understanding social interactions, which has been used in clinical studies to measure the quality of the therapeutic alliance. However, there is a lack of studies investigating the correlation between synchrony expressed on different levels: behavioural and neurophysiological. Furthermore, there are no studies that examine how the implementation of psychodramatic role-playing techniques, when individuals adopt the persona of a different character, may influence intrinsic biobehavioural synchrony between two parties. The present study, therefore, aims to uncover the relationship between behavioural and brain-to-brain synchrony across different role-playing techniques and elucidate the impact of these synchronies on participants' levels of anxiety and empathy. By using functional near-infrared imaging and behavioural coding in a dyadic role-playing paradigm (n = 41 dyads), the study found correlations between behavioural and brain-to-brain synchrony during naturalistic conversations, but not during role-play, implying a qualitative change in interpersonal synchrony when implementing role-playing techniques. Additionally, the study noted significant contributions of both behavioural and brain-to-brain synchrony as well as peripheral factors such as dyadic sex make-up and role immersion in predicting dyadic anxiety and empathy changes. Findings call for future studies to consider role-playing scenarios as a qualitatively different form of social interaction.

Through a teratological lens: A narrative review of exposure to stress and drugs of abuse during pregnancy on neurodevelopment

Teratological research shows that both prenatal stress and prenatal substance exposure have a significant impact on neurodevelopmental outcomes in children. Using human research, the purpose of this narrative review is to explore the degree to which these exposures may represent complex prenatal and postnatal risks for the development of cognition and behavior in children. An understanding of the HPA axis and its function during pregnancy as well as the types and operationalization of prenatal stress provide a context for understanding the direct and indirect mechanisms by which prenatal stress affects brain and behavior development. In turn, prenatal substance exposure studies are evaluated for their importance in understanding variables that indicate a potential interaction with prenatal stress including reactivity to novelty, arousal, and stress reactivity during early childhood. The similarities and differences between prenatal stress exposure and prenatal substance exposure on neurodevelopmental outcomes including arousal and emotion regulation, cognition, behavior, stress reactivity, and risk for psychopathology are summarized. Further considerations for teratological studies of prenatal stress and/or substance exposure include identifying and addressing methodological challenges, embracing the complexity of pre-and postnatal environments in the research, and the importance of incorporating parenting and resilience into future studies.

Dynamic self-regulation and coregulation of respiratory sinus arrhythmia in mother-child and father-child interactions: Moderating effects of proximal and distal stressors

This study examined how proximal and distal familial stressors influenced the real-time, dynamic individual and dyadic regulation of respiratory sinus arrhythmia (RSA) in mother-preschooler and father-preschooler interactions in at-risk families (N = 94, Mage = 3.03 years, 47% males, 77% White, 20% Latinx, data collected 2013-2017). Proximal stressors were operationalized as changing task demands (baseline, challenge, recovery) across a dyadic puzzle task. Distal stressors were measured as parent-reported stressful life events. Multilevel models revealed that greater proximal and distal stressors were related to weaker dynamic self-regulation of RSA in mothers, fathers, and children, and more discordant mother-child and father-child coregulation of RSA. Findings affirm that stress is transmitted across levels and persons to compromise real-time regulatory functioning in early, developmentally formative caregiver-child interactions.

Hyperscanning to explore social interaction among autistic minds

Hyperscanning - the monitoring of brain activity of two or more people simultaneously - has emerged to be a popular tool for assessing neural features of social interaction. This perspective article focuses on hyperscanning studies that use functional near-infrared spectroscopy (fNIRS), a technique that is very conducive to studies requiring naturalistic paradigms. In particular, we are interested in neural features that are related to social interaction deficits among individuals with autism spectrum disorders (ASD). This population has received relatively little attention in research using neuroimaging hyperscanning techniques, compared to neurotypical individuals. The study is outlined as follows. First, we summarize the findings about brain-behavior connections related to autism from previously published fNIRS hyperscanning studies. Then, we propose a preliminary theoretical framework of inter-brain coherence (IBC) with testable hypotheses concerning this population. Finally, we provide two examples of areas of inquiry in which studies could be particularly relevant for social-emotional/behavioral development for autistic children, focusing on intergenerational relationships in family units and learning in classroom settings in mainstream schools.

Facing infant cuteness: How nurturing care motivation and oxytocin system gene methylation are associated with responses to baby schema features

Baby schema features are a specific set of physical features-including chubby cheeks, large, low-set eyes, and a large, round head-that have evolutionary adaptive value in their ability to trigger nurturant care. In this study among nulliparous women (N = 81; M age = 23.60, SD = 0.44), we examined how sensitivity to these baby schema features differs based on individual variations in nurturant care motivation and oxytocin system gene methylation. We integrated subjective ratings with measures of facial expressions and electroencephalography (EEG) in response to infant faces that were manipulated to contain more or less pronounced baby schema features. Linear mixed effects analyses demonstrated that infants with more pronounced baby schema features were rated as cuter and participants indicated greater motivation to take care of them. Furthermore, infants with more pronounced baby schema features elicited stronger smiling responses and enhanced P2 and LPP amplitudes compared to infants with less pronounced baby schema features. Importantly, individual differences significantly predicted baby schema effects. Specifically, women with low OXTR methylation and high nurturance motivation showed enhanced differentiation in automatic neurophysiological responses to infants with high and low levels of baby schema features. These findings highlight the importance of considering individual differences in continued research to further understand the complexities of sensitivity to child cues, including facial features, which will improve our understanding of the intricate neurobiological system that forms the basis of caregiving behavior.

Examining the implications of contextual stress and maternal sensitivity for infants' cortisol responses to the still face paradigm

Infants' hypothalamic-pituitary-adrenocortical (HPA) axis responses to acute stressors are theorized to be shaped by parents' sensitive responsiveness to infants' cues. The strength and direction of the association between maternal sensitivity and infants' HPA responses may depend on the context in which maternal sensitivity is observed and on broader environmental sources of stress and support. In this preregistered study, we used data from 105 mothers and their 7-month-old infants to examine whether two empirically identified forms of contextual stress-poor maternal psychosocial wellbeing and family socioeconomic hardship-moderate the association between maternal sensitivity and infants' cortisol responses to the Still-Face Paradigm (SFP). Results indicated that maternal sensitivity during the free play and family socioeconomic hardship interacted to predict infants' cortisol responses to the SFP. Specifically, maternal sensitivity during this non-distressing interaction was negatively associated with cortisol responses only among infants whose mothers were experiencing relatively high socioeconomic hardship. Exploratory analyses revealed that poor maternal psychosocial wellbeing was positively associated with overall infant cortisol production during the SFP. Altogether, these findings suggest that experiences within early parent-infant attachment relationships and sources of contextual stress work together to shape infant HPA axis activity.

Severe PTSD is marked by reduced oxytocin and elevated vasopressin

Neuroendocrine analyses of posttraumatic stress disorder (PTSD) have generally focused on hypothalamic-pituitary-adrenal (HPA) axis alterations. In the present analyses, we examine two additional neuroendocrine factors that have been previously implicated in biological stress responses: oxytocin (OT) and arginine vasopressin (AVP). Here we examined basal neuropeptide status in military veterans clinically diagnosed with PTSD (n = 29) and in two non-traumatized comparison groups with previous stress exposure (n = 11 SWAT trainees and n = 21 ultramarathon runners). PTSD patients showed low levels of plasma OT and high levels of AVP. The ratio of AVP/OT robustly related to PTSD status, and emerged as a statistically plausible mediator of relationships between the number of personal traumatic experiences and subsequent PTSD symptom burden. Over the course of behavioral therapy for PTSD, measures of OT showed a significant but modest normalization. Plasma cortisol levels were not statistically different among the three groups. This study suggests that AVP/OT ratios may represent a neuroendocrine predictor of severe PTSD, as well as a potential treatment response biomarker.

Six types of loves differentially recruit reward and social cognition brain areas

Feelings of love are among the most significant human phenomena. Love informs the formation and maintenance of pair bonds, parent-offspring attachments, and influences relationships with others and even nature. However, little is known about the neural mechanisms of love beyond romantic and maternal types. Here, we characterize the brain areas involved in love for six different objects: romantic partner, one's children, friends, strangers, pets, and nature. We used functional magnetic resonance imaging (fMRI) to measure brain activity, while we induced feelings of love using short stories. Our results show that neural activity during a feeling of love depends on its object. Interpersonal love recruited social cognition brain areas in the temporoparietal junction and midline structures significantly more than love for pets or nature. In pet owners, love for pets activated these same regions significantly more than in participants without pets. Love in closer affiliative bonds was associated with significantly stronger and more widespread activation in the brain's reward system than love for strangers, pets, or nature. We suggest that the experience of love is shaped by both biological and cultural factors, originating from fundamental neurobiological mechanisms of attachment.

A Hypothalamic Perspective of Human Socioemotional Behavior

Historical evidence from stimulation and lesion studies in animals and humans demonstrated a close association between the hypothalamus and typical and atypical socioemotional behavior. A central hypothalamic contribution to regulation of socioemotional responses was also provided indirectly by studies on oxytocin and arginine vasopressin. However, a limited number of studies have so far directly investigated the contribution of the hypothalamus in human socioemotional behavior. To reconsider the functional role of the evolutionarily conserved hypothalamic region in regulating human social behavior, here I provide a synthesis of neuroimaging investigations showing that the hypothalamus is involved in multiple and diverse facets of human socioemotional behavior through widespread functional interactions with other cortical and subcortical regions. These neuroimaging findings are then integrated with recent optogenetics studies in animals demonstrating that the hypothalamus plays a more active role in eliciting socioemotional responses and is not simply a downstream effector of higher-level brain systems. Building on the aforementioned evidence, the hypothalamus is argued to substantially contribute to a continuum of human socioemotional behaviors promoting survival and preservation of the species that extends from exploratory and approaching responses facilitating social bonding to aggressive and avoidance responses aimed to protect and defend formed relationships.

Modulation of the attentional response to baby schema by testosterone in pedohebephilic men and its relation to the nurturing system

Previous fMRI research found increased brain responses in men with pedophilic interest to non-sexual pictures of child and animal faces. This raised the question of whether an aberrant nurturing system could be linked to pedophilia. To further explore this hypothesis, 20 pedohebephilic and 23 teleiophilic men performed a target detection task with adult versus infant human and animal faces, which measured selective attention towards the baby schema by comparing reaction times to infant versus adult targets that were presented amongst distractors of the other category. Since the response to baby schema can be influenced by steroid hormones, saliva samples were additionally collected to determine endogenous testosterone, progesterone, estradiol and cortisol. Contrary to expectations, all men did not react faster to infant than adult faces. Yet, pedohebephilic men were more distracted by infant's faces than teleiophilic men. Pedohebephilic men with higher testosterone were faster in orienting attention to infant targets in the context of adult distractors. This association was not observed in teleiophilic men. Our results support the idea of an overactive nurturing system in pedophilia, which may be influenced by the endogenous testosterone level.

In the eye of the beholder: Social traits predict motor simulation during naturalistic action perception

Previous research has robustly demonstrated that eye contact between actor and observer promotes the simulation of perceived actions into the observer's own motor system, which in turn facilitates social perception and communication. The socially relevant connotation embedded in eye contact may however be different for individuals with differing social traits. Here, we examined how "normal" (i.e. non-clinical) variability in self-reported social responsiveness/autistic traits, social anxiety and interpersonal relationship style (secure, avoidant or anxious attachment) influences neural motor simulation during action observation in different gaze conditions. To do so, we analyzed an existing dataset involving 124 adult participants (age range: 18-35 years) who underwent transcranial magnetic stimulation (TMS) while observing an actor performing simple hand actions and simultaneously engaging in eye contact or gazing away from the observer. Motor evoked potential (MEP) amplitudes were adopted as an index of motor resonance. Regression-based analyses highlighted the role of social responsiveness and secure attachment in shaping motor resonance, indicating that socially responsive motor resonance during dyadic gaze (i.e., MEPdirect > MEPaverted) was only observed in participants displaying high levels of these traits. Furthermore, a clustering analysis identified two to three distinct subgroups of participants with unique social trait profiles, showing a clear differentiation in motor resonant patterns upon different gaze cues that is in accordance with a recent neurobiological framework of attachment. Together, results demonstrate that motor resonance within a given social interaction may serve as a sensitive tracker of socio-interactive engagement, which allows to capture subclinical inter-individual variation in relevant social traits.

Abnormal amygdala volume moderates parenting and anxiety symptoms in children and adolescents with anxiety disorder

Anxiety disorders (AD) usually onset in childhood or adolescence and are related to brain development and early experiences during this period. As the hub of the fear circuit, the amygdala plays a crucial role in the development of emotional processing, and abnormalities in its structure and function are associated with anxiety disorders. We aim to uncover the amygdala volume's moderation between parenting and anxiety severity in children and adolescents with AD. 129 children and adolescents with anxiety and 135 age- and sex-matched Health controls (HC) using the publicly available Healthy Brain Network (HBN) dataset were included. Anxiety severity was measured using the Screen for Child Anxiety Related Disorders Self-report (SCARED-SR) and parenting was measured using the Alabama Parenting Questionnaire Self-Report (APQ-SR). We investigated age-related differences in amygdala volume in children and adolescents with anxiety disorders. Further, we examined the role of amygdala volume in moderating the association between parental involvement, particularly the maternal involvement, and anxiety symptoms in this population. We found larger bilateral amygdala in the AD group compared with the HC among the age range of 7-12. And increases in amygdala volume tended to negatively moderate the linear relationships between maternal involvement and anxiety symptoms in the AD group. These findings provide new evidence of abnormal brain alteration in children and adolescents with anxiety and may reflect proactive adaptations of adolescent brain development.

Maternal and paternal postpartum early mood and bonding

BACKGROUND

Whereas the maternal 'blues' has been widely researched, comparatively less is known about the "highs" following childbirth, and the relation between mothers and fathers' mood in this early period. We aimed to investigate the association between maternal 'blues' and 'highs' with paternal postpartum mood (here described as 'lows' and 'highs') in the early postpartum and their associations with the quality of child bonding.

METHODS

Women and their cohabitating male partners, fathers of the index child (N = 98 couples), attending an obstetric hospital unit completed questionnaires on mood, bonding and socio-demographics between the 3rd and the 5th postpartum day. We used generalised estimating equations to analyse the data.

RESULTS

The 'blues' scores were higher in mothers, whereas 'highs' and bonding were higher in fathers. Maternal 'blues' were significantly correlated with paternal 'lows' (rs = .23, p < .05) and maternal 'highs' were also associated with paternal 'highs' (rs = .22, p < .05). Parental 'highs' were significantly associated with better baby bonding (B = .13, p = .02).

CONCLUSIONS

Our study demonstrates moderate associations between both 'blues/lows' and 'highs' in mothers and fathers shortly after the birth of the child. Associations between mood, particularly 'highs', and bonding were similar for mothers and fathers. Greater consideration of 'blues/lows' and 'highs' in both parents is needed to promote adjustment in the postpartum period.

Oxytocin receptor function regulates neural signatures of pair bonding and fidelity in the nucleus accumbens

The formation of enduring relationships dramatically influences future behavior, promoting affiliation between familiar individuals. How such attachments are encoded to elicit and reinforce specific social behaviors in distinct ethological contexts remains unknown. Signaling via the oxytocin receptor (Oxtr) in the nucleus accumbens (NAc) facilitates social reward as well as pair bond formation between mates in socially monogamous prairie voles 1-9 . How Oxtr function influences activity in the NAc during pair bonding to promote affiliative behavior with partners and rejection of other potential mates has not been determined. Using longitudinal in vivo fiber photometry in wild-type prairie voles and those lacking Oxtr, we demonstrate that Oxtr function sex-specifically regulates pair bonding behaviors and associated activity in the NAc. Oxtr function influences prosocial behavior in females in a state-dependent manner. Females lacking Oxtr demonstrate reduced prosocial behaviors and lower activity in the NAc during initial chemosensory investigation of novel males. Upon pair bonding, affiliative behavior with partners and neural activity in the NAc during these interactions increase, but these changes do not require Oxtr function. Conversely, males lacking Oxtr display increased prosocial investigation of novel females. Using the altered patterns of behavior and activity in the NAc of males lacking Oxtr during their first interactions with a female, we can predict their future preference for a partner or stranger days later. These results demonstrate that Oxtr function sex-specifically influences the early development of pair bonds by modulating prosociality and the neural processing of sensory cues and social interactions with novel individuals, unmasking underlying sex differences in the neural pathways regulating the formation of long-term relationships.

Dyadic body competence predicts movement synchrony during the mirror game

The process of synchronizing our body movements with others is known to enhance rapport, affect, and prosociality. Furthermore, emerging evidence suggests that synchronizing activities may enhance cognitive performance. Unknown, by contrast, is the extent to which people's individual traits and experiences influence their ability to achieve and maintain movement synchrony with another person, which is key for unlocking the social and affective benefits of movement synchrony. Here, we take a dyad-centered approach to gain a deeper understanding of the role of embodiment in achieving and maintaining movement synchrony. Using existing data, we explored the relationship between body competence and body perception scores at the level of the dyad, and the dyad's movement synchrony and complexity while playing a 2.5-min movement mirroring game. The data revealed that dyadic body competence scores positively correlate with movement synchrony, but not complexity, and that dyadic body perception scores are not associated with movement synchrony or complexity. Movement synchrony was greater when the more experienced member of the dyad was responsible for copying movements. Finally, movement synchrony and complexity were stable across the duration of the mirror game. These findings show that movement synchrony is sensitive to the composition of the dyad involved, specifically the dyad's embodiment, illuminating the value of dyadic approaches to understanding body movements in social contexts.

Neural and affective responses to prolonged eye contact with parents in depressed and nondepressed adolescents

Eye contact improves mood, facilitates connectedness, and is assumed to strengthen the parent-child bond. Adolescent depression is linked to difficulties in social interactions, the parent-child bond included. Our goal was to elucidate adolescents' affective and neural responses to prolonged eye contact with one's parent in nondepressed adolescents (HC) and how these responses are affected in depressed adolescents. While in the scanner, 59 nondepressed and 19 depressed adolescents were asked to make eye contact with their parent, an unfamiliar peer, an unfamiliar adult, and themselves by using videos of prolonged direct and averted gaze, as an approximation of eye contact. After each trial, adolescents reported on their mood and feelings of connectedness, and eye movements and BOLD-responses were assessed. In HCs, eye contact boosted mood and feelings of connectedness and increased activity in inferior frontal gyrus (IFG), temporal pole, and superior frontal gyrus. Unlike HCs, eye contact did not boost the mood of depressed adolescents. While HCs reported increased mood and feelings of connectedness to the sight of their parent versus others, depressed adolescents did not. Depressed adolescents exhibited blunted overall IFG activity. These findings show that adolescents are particularly sensitive to eye contact and respond strongly to the sight of their parents. This sensitivity seems to be blunted in depressed adolescents. For clinical purposes, it is important to gain a better understanding of how the responsivity to eye contact in general and with their parents in particular, can be restored in adolescents with depression.

Altered cerebral white matter network topology and cognition in children with obstructive sleep apnea

OBJECTIVES

The study aimed to explore the underlying mechanisms of OSA-related cognitive impairment by investigating the altered topology of brain white matter networks in children with OSA.

METHODS

Graph theory was used to examine white matter networks' network topological properties in 46 OSA and 31 non-OSA children. All participants underwent MRI, polysomnography, and cognitive testing. The effects of the obstructive apnea-hypopnea index (OAHI) on topological properties of white matter networks and network properties on cognition were studied using hierarchical linear regression. Mediation analyses were used to explore whether white matter network properties mediated the effects of OAHI on cognition.

RESULTS

Children with OSA had significantly higher assortativity than non-OSA children. Furthermore, OAHI was associated with the nodal properties of several brain regions, primarily in the frontal and temporal lobes. The relationship between OAHI and verbal comprehension index was mediated through clustering coefficients in the right temporal pole of the superior temporal gyrus.

CONCLUSIONS

OSA affects the development of white matter networks in children's brains. Besides, the mediating role of white matter network properties between the OAHI and the verbal comprehension index provided neuroimaging evidence of impaired cognitive function in children with OSA.

Maternal behaviours disrupted by Gprasp2 deletion modulate neurodevelopmental trajectory in progeny

Autism spectrum disorders (ASDs) are known to present sex-specific differences. At the same time, understanding how maternal behaviours are affected by pathogenic mutations is crucial to translate research efforts since rearing may recursively modulate neurodevelopment phenotype of the progeny. In this work, we focused on the effects of Gprasp2 deletion in females and its impact in progeny care and development. Female mice, wild-type (WT), Gprasp2+/- (HET) or Gprasp2-/- (KO) mutants and their progeny were used and behavioural paradigms targeting anxiety, memory, maternal care, and other social behaviours were performed. Analysis of communication was carried out through daily recordings of ultrasonic vocalizations in isolated pups and cross-fostering experiments were performed to understand the effect of maternal genotype in pup development. We found that Gprasp2-/- females presented striking impairments in social and working memory. Females also showed disruptions in maternal care, as well as physiological and molecular alterations in the reproductive system and hypothalamus, such as the structure of the mammary gland and the expression levels of oxytocin receptor (OxtR) in nulliparous versus primiparous females. We observed alterations in pup communication, particularly a reduced number of calls in Gprasp2 KO pups, which resulted from an interaction effect of the dam and pup genotype. Cross-fostering mutant pups with wild-type dams rescued some of the early defects shown in vocalizations, however, this effect was not bidirectional, as rearing WT pups with Gprasp2-/- dams was not sufficient to induce significant phenotypical alterations. Our results suggest Gprasp2 mutations perturb social and working memory in a sex-independent manner, but impact female-specific behaviours towards progeny care, female physiology, and gene expression. These changes in mutant dams contribute to a disruption in early stages of progeny development. More generally, our results highlight the need to better understand GxE interactions in the context of ASDs, when female behaviour may present a contributing factor in postnatal neurodevelopmental trajectory.

A perspective-based analysis of attachment from prenatal period to second year postnatal life

Attachment is one of the foundational themes in the history of the psychological development of human beings. For this reason, we assume that it must be approached by taking into account multiple scientific perspectives. The present review aims at analyzing the state of the art regarding the genetic, neurobiological and cognitive mechanisms underlying the development of attachment bonding, considering the child as the frame of reference. We hypothesize that attachment may be present in prototypical forms even in the prenatal period, thus our analysis has a temporal origin in the intrauterine period preceding birth. The intrauterine period is assumed to be a period of maximum sensitivity to stimuli and in particular to those coming from a potential primary caregiver: the biological mother. We conclude with a reframing of the state of the art and propose that future research work would benefit from a superordinate model of attachment, capable of containing and regulating all its components and variables.

Infant carrying: Associations with parental reflective functioning, parental bonding and parental responses to infant crying

Infant carrying may have beneficial effects on the parent-infant relationship but only limited research has been conducted in this area. Therefore, the main aim of the current study was to investigate whether infant carrying is associated with parental reflective functioning, parental bonding, and parental (emotional) and behavioral responses to infant crying, key elements within the parent-infant relationship, promoting infant development. Parents reporting high levels (N = 389) of infant carrying (six times a week or daily) and parents reporting low levels (N = 128) of infant carrying (less than once a week or not at all) who participated in an online survey about the developing parent-infant relationship in Germany were included in the present study. Standardized questionnaires were used to assess parental reflective functioning, parental bonding impairments, and emotional responses to infant crying. Further insensitive (non-responsive and hostile) behaviors in response to infant crying were assessed. Parents with high levels of infant carrying showed better parental reflective functioning, lower parental bonding problems, less negative emotions, and less insensitive behaviors in response to infant crying.

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

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

Neonatal family-centered care: evidence and practice models

Although advances in neonatology have reduced the mortality rate of high-risk infants, sick newborns or pre-mature infants undergo more intensive monitoring, pain-ful procedures, and lengthy hospitalization, leading to pro-longed separation from their parents. In recent decades, the importance of parent-infant closeness early in life has become more apparent, especially in preterm infants who are prone to neurodevelopmental deficits. There is an increasing body of evidence regarding the benefits of family-centered care (FCC) in neonatal intensive care units. Key aspects related to neonatal FCC include the parents' presence in the ward and their participation in infants' daily care and decision-making processes. In addition, an environment that supports a private and comfortable space for each family member and infant, such as a single-family room, should be provided. To successfully implement FCC in neonatal intensive care units, the culture of care and hospital policies should be changed to successfully implement FCC in neonatal intensive care units, and appropriate training for medical staff is also required.

Interbrain substrates of role switching during mother-child interaction

Mother-child interaction is highly dynamic and reciprocal. Switching roles in these back-and-forth interactions serves as a crucial feature of reciprocal behaviors while the underlying neural entrainment is still not well-studied. Here, we designed a role-controlled cooperative task with dual EEG recording to explore how differently two brains interact when mothers and children hold different roles. When children were actors and mothers were observers, mother-child interbrain synchrony emerged primarily within the theta oscillations and the frontal lobe, which highly correlated with children's attachment to their mothers (self-reported by mothers). When their roles were reversed, this synchrony was shifted to the alpha oscillations and the central area and associated with mothers' perception of their relationship with their children. The results suggested an observer-actor neural alignment within the actor's oscillations, which was related to the actor-toward-observer emotional bonding. Our findings contribute to the understanding of how interbrain synchrony is established and dynamically changed during mother-child reciprocal interaction.

Global topology of human connectome is insensitive to early life environments - A prospective longitudinal study of the general population

The widely acknowledged detrimental impact of early adversity on child development has driven efforts to understand the underlying mechanisms that may mediate these effects within the developing brain. Recent efforts have begun to move beyond associating adversity with the morphology of individual brain regions towards determining if and how adversity might shape their interconnectivity. However, whether adversity effects a global shift in the organisation of whole-brain networks remains unclear. In this study, we assessed this possibility using parental questionnaire and diffusion imaging data from The Avon Longitudinal Study of Parents and Children (ALSPAC, N = 913), a prospective longitudinal study spanning more than 20 years. We tested whether a wide range of adversities-including experiences of abuse, domestic violence, physical and emotional cruelty, poverty, neglect, and parental separation-measured by questionnaire within the first seven years of life were significantly associated with the tractography-derived connectome in young adulthood. We tested this across multiple measures of organisation and using a computational model that simulated the wiring economy of the brain. We found no significant relationships between early exposure to any form of adversity and the global organisation of the structural connectome in young adulthood. We did detect local differences in the medial prefrontal cortex, as well as an association between weaker brain wiring constraints and greater externalising behaviour in adolescence. Our results indicate that further efforts are necessary to delimit the magnitude and functional implications of adversity-related differences in connectomic organization. RESEARCH HIGHLIGHTS: Diverse prospective measures of the early-life environment do not predict the organisation of the DTI tractography-derived connectome in young adulthood Wiring economy of the connectome is weakly associated with externalising in adolescence, but not internalising or cognitive ability Further work is needed to establish the scope and significance of global adversity-related differences in the structural connectome.

Attachment Orientations: Associations with Romantic Partners' Self-Regulation and Dyadic Coping

The ability to effectively cope with stress is impacted by early relationship experiences and, thus, is related to attachment security. We examined how different forms of attachment insecurity (namely, attachment anxiety and attachment avoidance) impact romantic partners' capacity for coping with stress individually (via self-regulation) and together (via dyadic coping) in a community sample of 261 heterosexual couples. We also explored links between these coping strategies and measures of well-being. Multiple regression analyses in this cross-sectional, self-report study indicated that attachment avoidance, but not anxiety, was linked to less effective dyadic coping. In men, this was also the case for partner's attachment avoidance. Attachment anxiety, but not avoidance, was related to self-regulation problems for women, while in men, both facets of attachment insecurity were negatively associated with self-regulation. Individual and dyadic coping strategies each uniquely contributed to individuals' well-being and satisfaction with life. Relationship interventions and counseling processes might benefit from sensitizing clients for biographical influences on their coping strategies.

The neurobiological effects of childhood maltreatment on brain structure, function, and attachment

Childhood maltreatment is a risk factor for psychopathologies, and influences brain development at specific periods, particularly during early childhood and adolescence. This narrative review addresses phenotypic alterations in sensory systems associated with specific types of childhood maltreatment exposure, periods of vulnerability to the neurobiological effects of maltreatment, and the relationships between childhood maltreatment and brain structure, function, connectivity, and network architecture; psychopathology; and resilience. It also addresses neurobiological alterations associated with maternal communication and attachment disturbances, and uses laboratory-based measures during infancy and case-control studies to elucidate neurobiological alterations in reactive attachment disorders in children with maltreatment histories. Moreover, we review studies on the acute effects of oxytocin on reactive attachment disorder and maltreatment and methylation of oxytocin regulatory genes. Epigenetic changes may play a critical role in initiating or producing the atypical structural and functional brain alterations associated with childhood maltreatment. However, these changes could be reversed through psychological and pharmacological interventions, and by anticipating or preventing the emergence of brain alterations and subsequent psychopathological risks.

Interpersonal neural synchrony and mental disorders: unlocking potential pathways for clinical interventions

Introduction

Interpersonal synchronization involves the alignment of behavioral, affective, physiological, and brain states during social interactions. It facilitates empathy, emotion regulation, and prosocial commitment. Mental disorders characterized by social interaction dysfunction, such as Autism Spectrum Disorder (ASD), Reactive Attachment Disorder (RAD), and Social Anxiety Disorder (SAD), often exhibit atypical synchronization with others across multiple levels. With the introduction of the "second-person" neuroscience perspective, our understanding of interpersonal neural synchronization (INS) has improved, however, so far, it has hardly impacted the development of novel therapeutic interventions.

Methods

To evaluate the potential of INS-based treatments for mental disorders, we performed two systematic literature searches identifying studies that directly target INS through neurofeedback (12 publications; 9 independent studies) or brain stimulation techniques (7 studies), following PRISMA guidelines. In addition, we narratively review indirect INS manipulations through behavioral, biofeedback, or hormonal interventions. We discuss the potential of such treatments for ASD, RAD, and SAD and using a systematic database search assess the acceptability of neurofeedback (4 studies) and neurostimulation (4 studies) in patients with social dysfunction.

Results

Although behavioral approaches, such as engaging in eye contact or cooperative actions, have been shown to be associated with increased INS, little is known about potential long-term consequences of such interventions. Few proof-of-concept studies have utilized brain stimulation techniques, like transcranial direct current stimulation or INS-based neurofeedback, showing feasibility and preliminary evidence that such interventions can boost behavioral synchrony and social connectedness. Yet, optimal brain stimulation protocols and neurofeedback parameters are still undefined. For ASD, RAD, or SAD, so far no randomized controlled trial has proven the efficacy of direct INS-based intervention techniques, although in general brain stimulation and neurofeedback methods seem to be well accepted in these patient groups.

Discussion

Significant work remains to translate INS-based manipulations into effective treatments for social interaction disorders. Future research should focus on mechanistic insights into INS, technological advancements, and rigorous design standards. Furthermore, it will be key to compare interventions directly targeting INS to those targeting other modalities of synchrony as well as to define optimal target dyads and target synchrony states in clinical interventions.

Interpersonal neural synchronization during social interactions in close relationships: A systematic review and meta-analysis of fNIRS hyperscanning studies

In recent years, researchers have used hyperscanning techniques to explore how brains interact during various human activities. These studies have revealed a phenomenon called interpersonal neural synchronization (INS), but little research has focused on the overall effect of INS in close relationships. To address this gap, this study aims to synthesize and analyze the existing literature on INS during social interactions in close relationships. We conducted a meta-analysis of 17 functional near-infrared spectroscopy (fNIRS) hyperscanning studies involving 1149 dyads participants, including romantic couples and parent-child dyads. The results revealed robust and consistent INS in the frontal, temporal, and parietal regions of the brain and found similar INS patterns in couples and parent-child studies, providing solid empirical evidence for the attachment theory. Moreover, the age of children and brain areas were significant predictors of the effect size in parent-child research. The developmental stage of children and the mismatched development of brain structures might be the crucial factors for the difference in neural performance in social and cognitive behaviors in parent-child dyads.

Social bonding in groups of humans selectively increases inter-status information exchange and prefrontal neural synchronization

Social groups in various social species are organized with hierarchical structures that shape group dynamics and the nature of within-group interactions. In-group social bonding, exemplified by grooming behaviors among animals and collective rituals and team-building activities in human societies, is recognized as a practical adaptive strategy to foster group harmony and stabilize hierarchical structures in both human and nonhuman animal groups. However, the neurocognitive mechanisms underlying the effects of social bonding on hierarchical groups remain largely unexplored. Here, we conducted simultaneous neural recordings on human participants engaged in-group communications within small hierarchical groups (n = 528, organized into 176 three-person groups) to investigate how social bonding influenced hierarchical interactions and neural synchronizations. We differentiated interpersonal interactions between individuals of different (inter-status) or same (intra-status) social status and observed distinct effects of social bonding on inter-status and intra-status interactions. Specifically, social bonding selectively increased frequent and rapid information exchange and prefrontal neural synchronization for inter-status dyads but not intra-status dyads. Furthermore, social bonding facilitated unidirectional neural alignment from group leader to followers, enabling group leaders to predictively align their prefrontal activity with that of followers. These findings provide insights into how social bonding influences hierarchical dynamics and neural synchronization while highlighting the role of social status in shaping the strength and nature of social bonding experiences in human groups.

Taking stock to move forward: Where the field of developmental psychopathology might be heading

In this paper, dedicated to Dante Cicchetti's contributions and enduring influence, we explore the prospective directions of developmental psychopathology. Our focus centers on key domains where Cicchetti's significant achievements have continually shaped our evolving thinking about psychological development. These domains include (a) the concepts of equifinality and multifinality, along with the challenges in predicting developmental trajectories, (b) the imperative to integrate wider sociocultural viewpoints into developmental psychopathology frameworks, (c) the interplay of genetic and environmental influences in developmental courses, (d) the significance of mental state language, and (e) the progress, or its absence, in the development of prevention and intervention tactics for children, adolescents, and their caregivers. While many of our forecasts regarding the future of developmental psychopathology may not materialize, we maintain optimistic that the essential ideas presented will influence the research agenda in this field and contribute to its growth over the next fifty years.

Does parental mental health mediate the association between parents' perceived stress and parent-infant bonding during the early COVID-19 pandemic?

BACKGROUND

The spread of the COVID-19 virus was declared a pandemic in March 2020. New restrictions such as 'lockdowns' and 'social distancing' created challenges for individuals' work-life balance, financial situation, family life, and physical and mental health. The global population's stress levels rose in response to these changes, leading to a widespread deterioration of mental health. One group particularly affected was parents of infants and very young children. Poor parental mental health may disrupt parent-infant bonding, with negative consequences for infant well-being and development.

AIMS

To consider parent-infant bonding in relation to parents' perceived stress and psychological distress during the first lockdown, and to examine whether associations of stress with parent-infant bonding were mediated by parental mental health.

METHODS

DREAMCORONA (n = 738: 471 mothers and 267 partners) is a sub-study of the prospective German cohort study 'DREAM'. The SPSS modelling tool PROCESS was used to assess whether parental mental health mediated the relationship between parents' perceived stress response to the COVID-19 pandemic and parent-infant bonding, while controlling for covariates.

RESULTS

Higher levels of parental stress were strongly associated with higher levels of depression, anxiety, and aggression symptoms for both parents. In addition, there was a significant relationship between parents' self-reported stress levels and parent-infant bonding. This relationship was mediated by symptoms of depression and anxiety for fathers and by symptoms of anger-hostility for both parents.

CONCLUSION

Increased parental stress during the early pandemic was associated with poorer parent-infant bonding. This has important implications for the management of any future public health crises.

Generation WhatsApp: inter-brain synchrony during face-to-face and texting communication

Texting has become one of the most prevalent ways to interact socially, particularly among youth; however, the effects of text messaging on social brain functioning are unknown. Guided by the biobehavioral synchrony frame, this pre-registered study utilized hyperscanning EEG to evaluate interbrain synchrony during face-to-face versus texting interactions. Participants included 65 mother-adolescent dyads observed during face-to-face conversation compared to texting from different rooms. Results indicate that both face-to-face and texting communication elicit significant neural synchrony compared to surrogate data, demonstrating for the first time brain-to-brain synchrony during texting. Direct comparison between the two interactions highlighted 8 fronto-temporal interbrain links that were significantly stronger in the face-to-face interaction compared to texting. Our findings suggest that partners co-create a fronto-temporal network of inter-brain connections during live social exchanges. The degree of improvement in the partners' right-frontal-right-frontal connectivity from texting to the live social interaction correlated with greater behavioral synchrony, suggesting that this well-researched neural connection may be specific to face-to-face communication. Our findings suggest that while technology-based communication allows humans to synchronize from afar, face-to-face interactions remain the superior mode of communication for interpersonal connection. We conclude by discussing the potential benefits and drawbacks of the pervasive use of texting, particularly among youth.

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

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

Shared Minds, Shared Feedback: tracing the influence of parental feedback on shared neural patterns

Parental feedback affects children in multiple ways. However, little is known about how children, family, and feedback types affect parental feedback neural mechanisms. The current study used functional near-infrared spectroscopy-based hyperscanning to observe 47 mother-daughter pairs's (mean age of mothers: 35.95 ± 3.99 yr old; mean age of daughters: 6.97 ± 0.75 yr old) brain synchronization in a jigsaw game under various conditions. Between parental negative feedback and praise conditions, mother-daughter brain in supramarginal gyrus, left dorsolateral prefrontal cortex, right inferior frontal gyrus, and right primary somatic (S1) differed. When criticized, conformity family-communication-patterned families had much worse brain synchronization in S1, left dorsolateral prefrontal cortex, and right Wernicke's region than conversational families. Resilient children had better mother-child supramarginal gyrus synchronicity under negative feedback. This study supports the importance of studying children's neurological development in nurturing environments to assess their psychological development.

Anhedonia mediates the relationships between childhood trauma and symptom severity of PTSD and depression, but not of social anxiety

BACKGROUND

Childhood trauma is a risk factor for developing multiple forms of psychopathology, including depression, posttraumatic stress disorder (PTSD), and social anxiety. Yet, the mechanisms linking childhood trauma and these psychopathologies remain less clear.

OBJECTIVE

Here we examined whether anhedonia, a reduced ability to experience pleasure, may mediate the relationship between childhood trauma and symptom severity of depression, PTSD, and social anxiety.

METHODS

A total of 230 trauma-exposed participants aged 18-75 were assessed for lifetime trauma exposure, including general and childhood traumatic events, anhedonia, and symptoms of depression, PTSD, and social anxiety.

RESULTS

Controlling for age, gender, and general lifetime trauma exposure, mediation analyses revealed a significant mediation effect of anhedonia for the relationship between childhood trauma and symptom severity of depression and PTSD, but not social anxiety. To better understand these significant mediation effects, we repeated the analyses separately for childhood abuse and neglect, and then for the various subtypes of each type of childhood trauma. Results showed a significant mediation effect of anhedonia on symptoms of both depression and PTSD in individuals who reported high emotional and sexual abuse levels. F Anhedonia was also found to mediate the relationship between both emotional and physical neglect and symptoms of depression and PTSD.

CONCLUSION

These findings refine our understanding of the ways in which childhood traumatic experiences may be associated with different mental health problems by increasing anhedonia. Anhedonia may be an important treatment target in survivors of childhood abuse and neglect.

Infant and preschool attachment, continuity and relationship to caregiving sensitivity: findings from a new population-based Australian cohort

BACKGROUND

Here, we report new prevalence and temporal stability data for child attachment and parental caregiving behaviour, from infancy (1 year) to preschool (4 years).

METHODS

Attachment (SSP) and caregiving data (MBQS) were from observations of parents and their infants and preschoolers, who represent the third generation of participants within an Australian longitudinal cohort.

RESULTS

At 1 year (n = 314 dyads) and at 4 years (n = 368 dyads), proportions assessed secure were 59% and 71%, respectively. Proportions assessed avoidant were 15% and 11%; ambivalent 9% and 6%, and disorganised 17% and 12%, at 1 and 4 years. Continuity of attachment pattern was highest for the infant secure group. Of dyads initially classified disorganised in infancy, 36% remained so at the preschool assessment. Attachment and caregiving continuities across the infancy-preschool period were highest for the stable secure attachment group and lowest for the stable insecure attachment group. Loss of secure attachment to mother by age 4 years correlated with decreased maternal caregiving sensitivity, and acquisition of secure status by age 4 was associated with increased maternal sensitivity. We found no difference in caregiving sensitivity scores for mothers and fathers for female and male preschool children.

CONCLUSIONS

The contemporary infant and preschool attachment proportions we report here closely mirror the patterns of those reported in prior decades, with an inclination towards secure base relationships. Our findings alert practitioners anew to the responsiveness of early attachment status to change in caregiving responsiveness and support ongoing investment in early identification of disorganised attachment.