The neural basis of responsive caregiving behaviour: Investigating temporal dynamics within the parental brain

Beauty and the brain - Investigating the neural and musical attributes of beauty during naturalistic music listening

Beauty judgments are common in daily life, but rarely studied in cognitive neuroscience. Here, in three studies, we searched for the neural mechanisms of musical beauty using a naturalistic free-listening paradigm applied to behavioral and neuroimaging recordings and validated by experts' judgments. In Study 1, 30 adults continuously rated the perceived beauty of three musical pieces using a motion sensor. This served to identify the musical passages that were inter-subjectively judged as more or less beautiful ('beautiful' vs. 'not-beautiful' passages). For identifying the consistent neural determinants of the perception of musical beauty, we utilized these ratings in Study 2, where 36 adults were recorded with functional magnetic resonance imaging (fMRI) while they listened attentively to the same pieces of Study 1. In Study 3, to identify the musicological features characterizing the beautiful and not-beautiful passages of Studies 1-2, we collected post-hoc questionnaires from 12 music-composition experts. Results from Study 2 evidenced focal activity in the orbitofrontal cortex when listening to beautiful passages whereas the not-beautiful passages were associated with bilateral supratemporal activity. Effective connectivity analysis discovered inhibition of auditory activation and neural communication with the right orbitofrontal cortex for listening to beautiful passages vs. intrinsic activation of auditory cortices and decreased coupling to orbitofrontal cortex for not-beautiful passages. Experts' questionnaires indicated that the beautiful passages were more melodic, calm, sad, slow, tonal, traditional, and simple than the ones rated negatively. In sum, we identified neural and psychological underpinnings of musical beauty, irrespectively of individual taste and listening biography.

A common neural response to perceiving but not implicitly regulating infant and adult affect in postpartum mothers

The transition to parenthood requires parents develop caregiving behaviors, such as the ability to identify their infant's emotions and regulate their own emotional response. Research has identified patterns of neural activation in parenting contexts that are interpreted as socioemotional processing. However, no prior research has directly tested whether mothers' neural responses to their infant's affect are the same as those involved in emotion perception/experience and regulation in other contexts. We employed conjunction analyses to clarify which components of mothers' neural response to viewing their infant's affect are shared with passively viewing and labeling adult affective faces (emotion perception/experience and implicit emotion regulation, respectively) in 24 mothers three months postpartum. Our results support a common neural response to viewing infant and adult affect in regions associated with emotion perception/experience (bilateral hippocampi, amygdalae, thalami, orbitofrontal cortex, and ventrolateral prefrontal cortex), but no areas of common response to viewing negative infant affect and implicitly regulating negative adult affect outside of the occipital lobe and cerebellum. This study provides corroborating evidence for shared neural patterns being involved in perceiving/experiencing infant and adult affect but not implicit regulation of infant and adult negative affect.

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.

Parents' Physiological Reactivity to Child Distress and Associations with Parenting Behaviour: A Systematic Review

This systematic review and narrative synthesis characterized parents' physiological stress responses to child distress and how parents' physiological and behavioural responses relate. The review was pre-registered with PROSPERO (#CRD42021252852). In total, 3,607 unique records were identified through Medline, Embase, PsycINFO, and CINAHL. Fifty-five studies reported on parents' physiological stress responses during their young child's (0-3 years) distress and were included in the review. Results were synthesized based on the biological outcome and distress context used and risk of bias was evaluated. Most studies examined cortisol or heart rate variability (HRV). Small to moderate decreases in parents' cortisol levels from baseline to post-stressor were reported across studies. Studies of salivary alpha amylase, electrodermal activity, HRV, and other cardiac outcomes reflected weak or inconsistent physiological responses or a paucity of relevant studies. Among the studies that examined associations between parents' physiological and behavioural responses, stronger associations emerged for insensitive parenting behaviours and during dyadic frustration tasks. Risk of bias was a significant limitation across studies and recommendations for future research are discussed.

Breastfeeding at Any Cost? Adverse Effects of Breastfeeding Pain on Mother-Infant Behavior

Breast milk is considered the ideal infant nutrition, and medical organizations encourage breastfeeding worldwide. Moreover, breastfeeding is often perceived as a natural and spontaneous socio-biological process and one of the fundamental roles of new mothers. While breastfeeding is beneficial, little scientific consideration has been given to its potential psychological challenges. Here, we investigate the phenomenon of breastfeeding pain in mothers and its association with maternal and infant behavioral regulation. During the postpartum weeks, the mother-infant dyad can be considered one allostatic unit directed at infant regulation and development. We hypothesize that pain comprises an allostatic challenge for mothers and will thus impair the capacity for dyadic regulation. To test this, we recruited 71 mothers with varying levels of breastfeeding pain and videotaped them with their infants (2-35 weeks old) during spontaneous face-to-face interactions. We quantified the individual differences in dyadic regulation by behaviorally coding the second-by-second affective expressions for each mother and infant throughout their interactions. We tested the extent to which breastfeeding pain alters affect regulation during mother-infant interactions. We discovered that mothers with severe breastfeeding pain express less affective expressions and less infant-directed gaze during interactive moments of engagement and play than mothers with no or moderate pain. Moreover, infants of mothers experiencing pain during breastfeeding express less affective expressions and more mother-directed gaze while interacting with their mothers than infants of mothers who are not in pain. This demonstrates that the allostatic challenge of maternal pain interferes with the behavioral regulation of both mothers and infants. Since the mother-infant dyad is a codependent allostatic unit, the allostatic challenges of one partner can impact the dyad and thus potentially impact child development, bonding, and mother and infant well-being. The challenges of breastfeeding should be considered in addition to the nutritional advances.

Development of the Paternal Brain in Humans throughout Pregnancy

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

Impact of the COVID-19 pandemic on maternal mental health, early childhood development, and parental practices: a global scoping review

BACKGROUND

In March 2020, the COVID-19 outbreak was declared a pandemic by the World Health Organization (WHO), generating stark economic and social repercussions that directly or indirectly affected families' wellbeing and health status.

AIMS

This review aims at mapping the existing evidence on the impact of the COVID-19 pandemic on maternal mental health, early childhood development, and parental practices, worldwide, to identify evidence gaps and better inform future delivery of care and health policy measures.

METHODS

Following the protocol defined by PRISMA-ScR, this scoping review has searched for relevant studies published between January 2020 and June 2021, selecting evidence sources based on pre-established criteria. From a total of 2,308 articles, data were extracted from 537 publications from 35 countries on all three health domains.

RESULTS

The combined stressors brought forth by the pandemic have exerted a heavy burden on the mental health of mothers and the development of young children, partly mediated by its impact on parental practices.

CONCLUSIONS

Despite remaining gaps, we have identified sufficient evidence pointing to an urgent need for more concerted global research efforts and rapid policy responses to timely address severe and pervasive negative impacts to the mental health of mothers and children at a key developmental stage.

On screen experiment showed that becoming a parent for the first time shifted people's priorities from themselves to their infant at 1 year of age

AIM

This study used a screen-based perceptual matching task to see how non-parents, people trying to get pregnant, and those who had given birth prioritised shapes and labels relating to self or infant conditions.

METHODS

The study took place at Aarhus University Hospital in Denmark from December 2016 to November 2021. Recruitment methods included family planning clinics, social media, online recruitment systems and local bulletin boards. The modified perceptual matching task linked five shapes to five labels, including self and infant.

RESULTS

We found that 67 males and females with a mean age of 24.4 ± 3 years, who had no plans to become parents in the near future, reacted faster and more accurately to self-shapes and labels (p < 0.001), which validated the experiment. The 56 participants aged 27.1 ± 4.4 years who were actively trying to become parents showed no statistically significant prioritisation. A subset of 21 participants aged 28.7 ± 4.4 years showed faster response times to infant than self-shapes and labels 1 year after giving birth (p < 0.001).

CONCLUSION

Healthy first-time parents showed faster reactions to infant than self-conditions 1 year after giving birth, in contrast to the other two groups.

Attentional Prioritization of Infant Faces in Parents: The Influence of Parents' Experiences of Care

Infant faces are prioritized by the attentional system in parents, resulting in a greater cognitive engagement in terms of response time. However, many biological, contextual and environmental factors relating to this cognitive mechanism have been left unexplored. To fill this gap, this study aims to (i) confirm that infant faces engage more attention compared to adult faces; (ii) investigate whether the attention to infant faces is affected early care experiences of parents; (iii) explore the effect of parents' sex by taking the amount of involvement with early childcare into consideration. 51 mothers and 46 fathers completed a modified Go/no-Go task, a brief sociodemographic questionnaire, the short version of the Adult Parental Acceptance-Rejection scale, and an ad-hoc question relating to the amount of parental involvement with early childcare. Parents' response times were slowed in the presence of infant versus adult faces. Parents whose mother was perceived as more sensitively accepting were more engaged by infant cues. By considering the amount of early parental involvement, the sex of parents did not significantly interact with the type of face. These findings provide new insights on the attention process in response to infant cues in parents and suggest that the investigation of experience-based factors may shed further light on this topic.

A magnetoencephalography study of first-time mothers listening to infant cries

Studies using magnetoencephalography (MEG) have identified the orbitofrontal cortex (OFC) to be an important early hub for a “parental instinct” in the brain. This complements the finding from functional magnetic resonance imaging studies linking reward, emotion regulation, empathy, and mentalization networks to the “parental brain.” Here, we used MEG in 43 first-time mothers listening to infant and adult cry vocalizations to investigate the link with mother–infant postpartum bonding scores and their level of sleep deprivation (assessed using both actigraphy and sleep logs). When comparing brain responses to infant versus adult cry vocalizations, we found significant differences at around 800–1,000 ms after stimuli onset in the primary auditory cortex, superior temporal gyrus, hippocampal areas, insula, precuneus supramarginal gyrus, postcentral gyrus, and posterior cingulate gyrus. Importantly, mothers with weaker bonding scores showed decreased brain responses to infant cries in the auditory cortex, middle and superior temporal gyrus, OFC, hippocampal areas, supramarginal gyrus, and inferior frontal gyrus at around 100–300 ms after the stimulus onset. In contrast, we did not find correlations with sleep deprivation scores. The significant decreases in brain processing of an infant’s distress signals could potentially be a novel signature of weaker infant bonding in new mothers and should be investigated in vulnerable populations.

Empathy for others versus for one's child: Associations with mothers' brain activation during a social cognitive task and with their toddlers' functioning

Caregivers who are higher in dispositional empathy tend to have children with better developmental outcomes; however, few studies have considered the role of child-directed (i.e., "parental") empathy, which may be relevant for the caregiver-child relationship. We hypothesized that mothers' parental empathy during their child's infancy will be a stronger predictor of their child's social-emotional functioning as a toddler than will mothers' dispositional empathy. We further explored whether parental and dispositional empathy have shared or distinct patterns of neural activation during a social-cognitive movie-watching task. In 118 mother-infant dyads, greater parental empathy assessed when infants were 6 months old was associated with more social-emotional competencies and fewer problems in the children 1 year later, even after adjusting for dispositional empathy. In contrast, dispositional empathy was not associated with child functioning when controlling for parental empathy. In a subset of 20 mothers, insula activation was positively associated with specific facets of both dispositional and parental empathy, whereas right temporoparietal junction activation was associated only with parental empathy. Thus, dispositional and parental empathy appear to be dissociable by both brain and behavioral metrics. Parental empathy may be a viable target for interventions, especially for toddlers at risk for developing social-emotional difficulties.

Deliberate control over facial expressions in motherhood. Evidence from a Stroop-like task

The deliberate control of facial expressions is an important ability in human interactions, in particular for mothers with prelinguistic infants. Because research on this topic is still scarce, we investigated the control over facial expressions in a Stroop-like paradigm. Mothers of 2-6 months old infants and nullipara women produced smiles and frowns in response to verbal commands written on distractor faces of adults or infants showing expressions of happiness or anger/distress. Analyses of video recordings with a machine classifier for facial expression revealed pronounced effects of congruency between the expressions required by the participants and those displayed by the face stimuli on the onset latencies of the deliberate facial expressions. With adult distractor faces this Stroop effect was similar whether participants smiled or frowned. With infant distractor faces mothers and non-mothers showed indistinguishable Stroop effects on smile responses; however, for frown responses, the Stroop effect in mothers was smaller than in non-mothers. We suggest that for frown responses in mothers when facing infants, the effect of mimicry or stimulus response compatibility, leading to the Stroop effect, is offset by a caregiving response or empathy.

Parent-to-Child Anxiety Transmission Through Dyadic Social Dynamics: A Dynamic Developmental Model

The intergenerational transmission of psychopathology is one of the strongest known risk factors for childhood disorder and may be a malleable target for prevention and intervention. Anxious parents have distinct parenting profiles that impact socioemotional development, and these parenting effects may result in broad alterations to the biological and cognitive functioning of their children. Better understanding the functional mechanisms by which parental risk is passed on to children can provide (1) novel markers of risk for socioemotional difficulties, (2) specific targets for intervention, and (3) behavioral and biological indices of treatment response. We propose a developmental model in which dyadic social dynamics serve as a key conduit in parent-to-child transmission of anxiety. Dyadic social dynamics capture the moment-to-moment interactions between parent and child that occur on a daily basis. In shaping the developmental trajectory from familial risk to actual symptoms, dyadic processes act on mechanisms of risk that are evident prior to, and in the absence of, any eventual disorder onset. First, we discuss dyadic synchrony or the moment-to-moment coordination between parent and child within different levels of analysis, including neural, autonomic, behavioral, and emotional processes. Second, we discuss how overt emotion modeling of distress is observed and internalized by children and later reflected in their own behavior. Thus, unlike synchrony, this is a more sequential process that cuts across levels of analysis. We also discuss maladaptive cognitive and affective processing that is often evident with increases in child anxiety symptoms. Finally, we discuss additional moderators (e.g., parent sex, child fearful temperament) that may impact dyadic processes. Our model is proposed as a conceptual framework for testing hypotheses regarding dynamic processes that may ultimately guide novel treatment approaches aimed at intervening on dyadically linked biobehavioral mechanisms before symptom onset.

Does neural face processing explain effects of an attachment-based intervention on maternal sensitivity? A randomized controlled study including pre- and postintervention measures

BACKGROUND

Although there is a large body of literature highlighting the behavioral effects of parenting interventions, studies on the neurocognitive mechanisms involved in such intervention effects remain scarce.

PURPOSE

The aim of the current study was to test whether changes in neural face processing (as reflected in N170 amplitudes) would act as a mediator in the association between the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) and maternal sensitivity.

METHODS

A total of 66 mothers of whom a random 33% received the VIPP-SD and the others a "dummy" intervention participated in pre- and postintervention assessments. We recorded mothers' electroencephalographic (EEG) activity in response to photographs of children's neutral, happy, and angry facial expressions. Maternal sensitivity was observed while mothers interacted with their offspring in a semi-structured play situation.

RESULTS

In contrast with our expectations, we did not find evidence for mediation of intervention effects on maternal sensitivity by the N170.

CONCLUSION

We discuss that parenting support programs may yield different effects on neurocognitive processes depending on the population and provide recommendations for future research. Our study underscores the importance of reporting null findings and preregistering studies in the field of neurocognitive research.

Advancing the RDoC initiative through the assessment of caregiver social processes

The relationships infants and young children have with their caregivers are fundamental to their survival and well-being. Theorists and researchers across disciplines have attempted to describe and assess the variation in these relationships, leading to a general acceptance that caregiving is critical to understanding child functioning, including developmental psychopathology. At the same time, we lack consensus on how to assess these fundamental relationships. In the present paper, we first review research documenting the importance of the caregiver-child relationship in understanding environmental risk for psychopathology. Second, we propose that the National Institute of Mental Health's Research Domain Criteria (RDoC) initiative provides a useful framework for extending the study of children's risk for psychopathology by assessing their caregivers' social processes. Third, we describe the units of analysis for caregiver social processes, documenting how the specific subconstructs in the domain of social processes are relevant to the goal of enhancing knowledge of developmental psychopathology. Lastly, we highlight how past research can inform new directions in the study of caregiving and the parent-child relationship through this innovative extension of the RDoC initiative.

Increased activation in the bilateral anterior insulae in response to others in pain in mothers compared to non-mothers

Empathy allows us to share emotions and encourages us to help others. It is especially important in the context of parenting where children's wellbeing is dependent on their parents' understanding and fulfilment of their needs. To date, little is known about differences in empathy responses of parents and non-parents. Using stimuli depicting adults and children in pain, this study focuses on the interaction of motherhood and neural responses in areas associated with empathy. Mothers showed higher activation to both adults and children in pain in the bilateral anterior insulae, key regions of empathy for pain. Additionally, mothers more strongly activated the inferior frontal, superior temporal and the medial superior frontal gyrus. Differences between adult and child stimuli were only found in occipital areas in both mothers and non-mothers. Our results suggest a stronger neural response to others in pain in mothers than non-mothers regardless of whether the person is a child or an adult. This could indicate a possible influence of motherhood on overall neural responses to others in pain rather than motherhood specifically shaping child-related responses. Alternatively, stronger responses to others in pain could increase the likelihood for women to be in a relationship and subsequently to have a child.

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

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

Maternal perinatal anxiety and neural responding to infant affective signals: Insights, challenges, and a road map for neuroimaging research

Anxiety symptoms are common among women during pregnancy and the postpartum period, potentially having detrimental effects on both mother and child's well-being. Perinatal maternal anxiety interferes with a core facet of adaptive caregiving: mothers' sensitive responsiveness to infant affective communicative 'cues.' This review summarizes the current research on the neural correlates of maternal processing of infant cues in the presence of perinatal anxiety, outlines its limitations, and offers next steps to advance future research. Functional neuroimaging studies examining the neural circuitry involved in, and electrophysiological studies examining the temporal dynamics of, processing infant cues during pregnancy and postpartum are reviewed. Studies have generally indicated mixed findings, although emerging themes suggest that anxiety may be implicated in several stages of processing infant cues- detection, interpretation, and reaction- contingent upon cue valence. Limitations include inconsistent designs, lack of differentiation between anxiety and depression symptoms, and limited consideration of parenting-specific (versus domain-general) anxiety. Future studies should incorporate longitudinal investigation of multiple levels of analysis spanning neural, cognitive, and observed aspects of sensitive caregiving.

Neurobiological changes during the peripartum period: implications for health and behavior

Pregnancy and the transition to parenthood is an important period marked by dramatic neurobiological and psychosocial changes that may have implications for the health of women and offspring. Although human and non-human animal research suggests that the brain undergoes alterations during the peripartum period, these changes are poorly understood. Here, we review existing research, particularly human neuroimaging and psychophysiological research, to examine changes in brain structure and function during the peripartum period and discuss potential implications for the health of women and offspring. First, we discuss the potential causes of these changes across pregnancy, including physiological and psychosocial factors. Next, we discuss the evidence for structural and functional changes in the brain during pregnancy and into the postpartum period, noting the need for research conducted prospectively across human pregnancy. Finally, we propose potential models of individual differences in peripartum neurobiological changes (i.e. hypo-response, typical response, hyper-response) and emphasize the need to consider trajectories of change in addition to pre-existing factors that may predict maternal adjustment to parenthood. We suggest that the consideration of individual differences in neurobiological trajectories across pregnancy may contribute to a better understanding of risk for negative health and behavior outcomes for women and offspring.

Development of the paternal brain in expectant fathers during early pregnancy

The human parenting brain network mediates caregiving behaviors. When exposed to the stimuli of their infants, compared with non-parents, both fathers and mothers exhibit distinct patterns of neural activation. As human males, relative to females, do not undergo robust physiological changes during pregnancy, when and how the paternal brain networks begin to form remains unclear. Thus, using functional MRI, we examined brain activation in response to infant-interaction videos in two groups, childless males and first-time expectant fathers during their partners' early pregnancy before remarkable changes in their partners' appearances commenced. Multivoxel pattern analysis revealed that expectant fathers' left anterior insula and inferior frontal gyrus showed incipient changes in response to parenthood during early pregnancy. Furthermore, these changes were associated with several paternal traits, such as a negative image toward parenting. Such external factors might influence the paternal brain's development during early pregnancy.

Maternal brain in the process of maternal-infant bonding: Review of the literature

The mother-infant relationship is one of the most important bonds among all mammals and develops when a mother shows emotional and physical attention toward her infant. Studies suggest that maternal brain alterations, including structural and functional changes, may help mothers to form a strong bond with their infant. Investigation of mothers' unique response to her own infant, when smiling, crying or playing, could be the first step to uncover the neural bases of maternal-infant bonding. Studies are beginning to explore maternal brain changes underlying the process of mother-infant bonding. In this short review, we present an overview of the growing literature about maternal brain changes and neural responses to infant stimuli, which may underlie the process of forming the maternal-infant bond in healthy, non-clinical samples. Taken together, the maternal brain network consists mostly of areas related to salience/reward and emot processing, including the precuneus cortex, medial frontal cortex, anterior cingulate cortex, orbitofrontal cortex, caudate and nucleus accumbens, amygdala, and insula. Recommendations for future research are also discussed.

The influence of cognitive load on maternal postural sway and heart rate in response to infant vocalizations

Infants communicate their emotions to their caregivers through cries and laughter. Recent work suggests that adaptive parenting requires cognitive regulation of intuitive behaviors toward infants' signals. In this study, we examined the effects of cognitive regulation on mothers' unconscious behavioral and cardiac responses to infant cries and laughs. In all, 55 mothers took part in this study. To manipulate cognitive load, mothers were asked to memorize alphabet characters (two letters in the low cognitive load condition and eight in the high cognitive load condition). Then, they heard infant vocalizations (cries or laughs) for 6 s. During this time, we measured mothers' behavioral (center of pressure, an index of approach-avoidance behavior) and physiological (heart rate) responses. Regardless of vocalization type (infant cries or laughs), high cognitive load increased mothers' forward movement toward the infant sounds as well as mothers' heart rate. These findings advance our understanding of the link between executive function and maternal response to infant signals by utilizing postural and physiological measures of maternal response during memory tasks that require cognitive resources.

Interpersonal Neural Entrainment during Early Social Interaction

Currently, we understand much about how children's brains attend to and learn from information presented while they are alone, viewing a screen - but less about how interpersonal social influences are substantiated in the brain. Here, we consider research that examines how social behaviors affect not one, but both partners in a dyad. We review studies that measured interpersonal neural entrainment during early social interaction, considering two ways of measuring entrainment: concurrent entrainment (e.g., 'when A is high, B is high' - also known as synchrony) and sequential entrainment ('changes in A forward-predict changes in B'). We discuss possible causes of interpersonal neural entrainment, and consider whether it is merely an epiphenomenon, or whether it plays an independent, mechanistic role in early attention and learning.

Gradient theories of brain activation: A novel application to studying the parental brain

PURPOSE OF REVIEW

Parental brain research primarily employs general-linear-model-based (GLM-based) analyses to assess blood-oxygenation-level-dependent responses to infant auditory and visual cues, reporting common responses in shared cortical and subcortical structures. However, this approach does not reveal intermixed neural substrates related to different sensory modalities. We consider this notion in studying the parental brain.

RECENT FINDINGS

Spatial independent component analysis (sICA) has been used to separate mixed source signals from overlapping functional networks. We explore relative differences between GLM-based analysis and sICA as applied to an fMRI dataset acquired from women while they listened to infant cries or viewed infant sad faces.

SUMMARY

There is growing appreciation for the value of moving beyond GLM-based analyses to consider brain functional organization as continuous, distributive, and overlapping gradients of neural substrates related to different sensory modalities. Preliminary findings suggest sICA can be applied to the study of the parental brain.

Exposure to early and persistent maternal depression impairs the neural basis of attachment in preadolescence

Maternal depression increases child vulnerability to psychopathology, loneliness, and social maladjustment; yet, its long-term effects on the social brain are unknown. In this prospective longitudinal study we examined the impact of early and persistent maternal depression on the neural basis of attachment in preadolescence. A community cohort was followed in two groups; children exposed to maternal depression from birth to 6 years and healthy controls. At 9 months and 6 years, mother-child interactions were coded for maternal sensitivity and affect synchrony and salivary oxytocin levels were assessed at 6 years. At preadolescence (11-13 years), children underwent magnetoencephalography (MEG) while exposed to own versus unfamiliar mother-child interaction. Own interaction elicited greater response in beta- and gamma-band oscillations across a wide cluster in temporal and insular cortices, including the Superior Temporal Sulcus, Superior Temporal Gyrus, Inferior Temporal Gyrus, and insula. Beta activations were predicted by maternal sensitivity across early childhood and gamma by affect synchrony. Oxytocin was related to beta response to social cues. Maternal depression impacted child's brain response in two ways. First, maternal depression significantly increased the prevalence of child affective disorder and such children showed no neural differentiation between attachment and non-attachment stimuli. Second, maternal depression decreased maternal sensitivity, affect synchrony, and child oxytocin across early childhood and these were longitudinally associated with aberrant neural response to attachment-specific and social-general cues in preadolescence. Our findings are the first to describe mechanisms by which maternal depression impairs the neural basis of attachment at the transition to adolescence and advocate the need for relationship-focused early interventions.

Differential Effects of Infant Vocalizations on Approach-Avoidance Postural Movements in Mothers

Infant vocalization plays a pivotal role in communicating infant mood to parents and thereby motivating parenting responses. Although many psychological and neural responses to infant vocalization have been reported, few studies have examined maternal approach-avoidance behavior in response to infant vocalization. Thus, this research sought to determine how infant emotional vocalization affects maternal behavior. Twenty mothers participated in this behavioral study, all of whom had infants of 24 months old or less. In the experiment, they stood on a Balance Board that collected real-time data regarding center of pressure (COP), while listening to a series of infant vocalizations including cry, laugh, and babbling. They then listened to the same vocalizations for a second time and rated their felt emotions in response to each vocalization. The participants demonstrated significant postural movements of approaching in response to cry stimuli or to stimuli regarded as highly urgent. In contrast, they demonstrated postural movement of avoidance in response to laugh vocalization. These findings suggest that parenting behavior in response to infant emotional vocalization is regulated not by the pleasant-unpleasant axis but by the urgency of the stimulus.

Mothers' neural responses to infant faces are associated with activation of the maternal care system and observed intrusiveness with their own child

Certain infant facial characteristics, referred to as baby schema, are thought to automatically trigger parenting behavior and affective orientation toward infants. Electroencephalography (EEG) is well suited to assessing the intuitive nature and temporal dynamics of parenting responses, due to its millisecond temporal resolution. Little is known, however, about the relations between neural processing of infant cues and actual parenting behavior in a naturalistic setting. In the present study we examined the event-related potentials (ERPs) of mothers (N = 33) watching infant faces of varying attractiveness, in relation to activation of the maternal care system and the mothers’ observed parenting behavior (sensitivity, nonintrusiveness) with their own child (2–6 years old). The results revealed that, irrespective of the cuteness of the infant face, mothers’ neural processing of infant faces involved both early P1 and P2 components (related to orienting/detecting processes) and late positive potentials (LPPs; related to more controlled cognitive evaluation/attentional engagement). Increased early detection and processing of infant faces (reflected by P1 and P2 activity) was related to increased activation of the parental care system. In later stages of face processing, increased attentional engagement with infant faces (as reflected by LPP activity) was associated with more intrusiveness of a mother with her own child during interaction. These findings suggest that individual variations in responses to infant stimuli are associated with individual differences in parental care system activation and parenting quality. Furthermore, the parental care system might be activated relatively automatically, but actual parenting and caregiving behavior requires more conscious control.

Nonmaternal care: a half-century of research

This paper aims to serve three purposes, providing: 1. a half-century retrospective on research in on nonmaternal care of the young, with an emphasis on key advances; 2. a commentary on the research papers in this special issue on nonmaternal care; and 3. a summary of nonmaternal care among hunting-and-gathering cultures-representing the human Environments of Evolutionary Adaptedness (EEAs)-in the broader context of human evolution. While the research being done now is excellent and uses appropriate evolutionary theory and cutting-edge methods ranging across behavioral biology (field and laboratory observational studies, controlled experiments, careful behavioral measures, energetics, neurotransmitter function, neuroendocrinology, neuroimaging, and genetics, among others), it is difficult to make generalizations beyond stating that nonmaternal care is a multifaceted evolved function in some species, which usually contributes to the reproductive success of the mother and the survival of the young. Why it evolved when and where it did is not an impenetrable question, but needs further research. The same is true for the mechanistic biology of various types of allomaternal care. I conclude with some observations on historical changes in non-maternal care since the hunting-gathering era, including in industrial and postindustrial cultures. It is evident that in the human species at least, many arrangements for care of the young are possible and adaptive.

Brain plasticity in pregnancy and the postpartum period: links to maternal caregiving and mental health

Pregnancy and the postpartum period involve numerous physiological adaptations that enable the development and survival of the offspring. A distinct neural plasticity characterizes the female brain during this period, and dynamic structural and functional changes take place that accompany fundamental behavioral adaptations, stimulating the female to progress from an individual with self-directed needs to being responsible for the care of another life. While many animal studies detail these modifications, an emerging body of research reveals the existence of reproduction-related brain plasticity in human mothers too. Additionally, associations with aspects of maternal caregiving point to adaptive changes that benefit a woman's transition to motherhood. However, the dynamic changes that affect a woman's brain are not merely adaptive, and they likely confer a vulnerability for the development of mental disorders. Here, we review the changes in brain structure and function that a woman undergoes during the peripartum period, outlining associations between these neural alterations and different aspects of maternal care. We additionally discuss peripartum mood disorders and postpartum psychosis, and review the neuroimaging studies that investigate the neural bases of these conditions.

Periaqueductal gray and emotions: the complexity of the problem and the light at the end of the tunnel, the magnetic resonance imaging

The periaqueductal gray (PAG) is less referred in relationship with emotions than other parts of the brain (e.g. cortex, thalamus, amygdala), most probably because of the difficulty to reach and manipulate this small and deeply lying structure. After defining how to evaluate emotions, we have reviewed the literature and summarized data of the PAG contribution to the feeling of emotions focusing on the behavioral and neurochemical considerations. In humans, emotions can be characterized by three main domains: the physiological changes, the communicative expressions, and the subjective experiences. In animals, the physiological changes can mainly be studied. Indeed, early studies have considered the PAG as an important center of the emotions-related autonomic and motoric processes. However, in vivo imaging have changed our view by highlighting the PAG as a significant player in emotions-related cognitive processes. The PAG lies on the crossroad of networks important in the regulation of emotions and therefore it should not be neglected. In vivo imaging represents a good tool for studying this structure in living organism and may reveal new information about its role beyond its importance in the neurovegetative regulation.

Specification of Change Mechanisms in Pregnant Smokers for Malleable Target Identification: A Novel Approach to a Tenacious Public Health Problem

Maternal smoking during pregnancy (MSDP) continues to be a leading modifiable risk factor for perinatal complications and a range of neurodevelopmental and cardio-metabolic outcomes across the lifespan. Despite 40 years of intervention research less than one in five pregnant smokers who receive an intervention quit by delivery. Within this context, recognition of pregnancy is commonly associated with abrupt suspension or reduction of smoking in the absence of intervention, yet has not been investigated as a volitional target. The goal of this article is to provide the empirical foundation for a novel direction of research aimed at identifying malleable targets for intervention through the specification of behavior change mechanisms specific to pregnant women. To do so, we: (1) summarize progress on MSDP in the United States generated from conventional empirical approaches to health behavior change; (2) discuss the phenomenon of spontaneous change in the absence of intervention among pregnant smokers to illustrate the need for mechanistic specification of behavior change motivated by concern for fetal well-being; (3) summarize component processes in neurobiological models of parental and non-parental social behaviors as a conceptual framework for understanding change mechanisms during pregnancy; (4) discuss the evidence for the malleability of these processes to support their translational relevance for preventive interventions; and (5) propose a roadmap for validating the proposed change mechanism using an experimental medicine approach. A greater understanding of social and interpersonal processes that facilitate health behavior change among expectant mothers and how these processes differ interindividually could yield novel volitional targets for prenatal interventions. More broadly, explicating other-oriented mechanisms of behavior change during pregnancy could serve as a paradigm for understanding how social and interpersonal processes positively influence health behaviors across the lifespan.

The Affective Core of Emotion: Linking Pleasure, Subjective Well-Being, and Optimal Metastability in the Brain

Arguably, emotion is always valenced-either pleasant or unpleasant-and dependent on the pleasure system. This system serves adaptive evolutionary functions; relying on separable wanting, liking, and learning neural mechanisms mediated by mesocorticolimbic networks driving pleasure cycles with appetitive, consummatory, and satiation phases. Liking is generated in a small set of discrete hedonic hotspots and coldspots, while wanting is linked to dopamine and to larger distributed brain networks. Breakdown of the pleasure system can lead to anhedonia and other features of affective disorders. Eudaimonia and well-being are difficult to study empirically, yet whole-brain computational models could offer novel insights (e.g., routes to eudaimonia such as caregiving of infants or music) potentially linking eudaimonia to optimal metastability in the pleasure system.

Duration of motherhood has incremental effects on mothers' neural processing of infant vocal cues: a neuroimaging study of women

The transition to motherhood, and the resultant experience of caregiving, may change the way women respond to affective, infant signals in their environments. Nonhuman animal studies have robustly demonstrated that mothers process both infant and other salient signals differently from nonmothers. Here, we investigated how women with and without young infants respond to vocalisations from infants and adults (both crying and neutral). We examined mothers with infants ranging in age (1-14 months) to examine the effects of duration of maternal experience. Using functional magnetic resonance imaging, we found that mothers showed greater activity than nonmothers to vocalisations from adults or infants in a range of cortical regions implicated in the processing of affective auditory cues. This main effect of maternal status suggests a general difference in vocalisation processing across infant and adult sounds. We found that a longer duration of motherhood, and therefore more experience with an infant, was associated with greater infant-specific activity in key parental brain regions, including the orbitofrontal cortex and amygdala. We suggest that these incremental differences in neural activity in the maternal brain reflect the building of parental capacity over time. This is consistent with conceptualizations of caregiving as a dynamic, learning process in humans.

The development of attachment: Integrating genes, brain, behavior, and environment

In humans, as in other animal species, early caregiver-infant interactions influence physiological and psychological processes by modulating brain sensitivity. Furthermore, early social interaction between caregiver and infant influences infants' cognitive and socioemotional development, and subsequently the development of social, familial, and romantic relationships later in life. Here, we have collected longitudinal and cross-sectional empirical studies as well as review and perspective articles that focus on human or non-human mammals with the aim to investigate how genetic, hormonal, behavioural, and environmental factors, as well as cultural contexts, regulate early interactional experiences, and how these experiences translate into social and non-social competences later in life (see Graphical Abstract).