Changes in Cortical Sensitivity to Infant Facial Cues From Pregnancy to Motherhood Predict Mother-Infant Bonding

Baby don't cry: Unconscious sensitivity to sad baby faces

Infant cues are known to play a crucial role in eliciting caregiving responses, making them essential for survival and development of offspring. Yet, it is still unknown whether infant faces may attract adults' attention when presented under the level of consciousness. Using a disengagement task and an eye-tracker procedure, this study investigated whether the subliminal exposure to emotional baby vs adult faces affects mothers' (N = 57) and non-mothers' (N = 57) attention disengagement. Independently from their parental status, women had longer saccadic latencies following subliminal sad baby faces, compared to happy baby faces and sad adult faces. These findings indicate that infants' sad facial expressions below the threshold of conscious perception can induce an attentional bias, thus representing a highly salient social signal for the human species.

Exploring mothers' perspectives on the early mother-infant relationship to inform midwifery practice: A qualitative study

BACKGROUND

The mother-infant relationship plays a crucial role in individual and community health. The nature of the mother-infant relationship can influence the social and emotional development of the infant, impacting their lifelong health. Midwives are key in providing health promotion for women and babies and are ideally placed to support women during the early development of the mother-infant relationship.

AIMS

This study aimed to explore new mothers' perspectives on developing the early mother-infant relationship to inform midwifery practice.

METHODS

This study is phase one of a mixed-method, exploratory sequential design project. In this phase, 14 women were interviewed within six weeks of birth to explore experiences that influenced the developing relationship with their baby. To support reflection women were provided with a visual prompt activity. These interviews informed the co-design workshops to develop an intervention to support midwives to promote the early mother infant relationship. A research protocol was published prior to undertaking the study, however as this research did not seek to modify or measure any heath related outcomes it was not registered as a clinical trial.

RESULTS

Key themes from the interviews included: making moments that matter; the role of the village; feeling like I'm winning; supportive health professionals, and forming a new family. These themes underpinned strategies to support the mother-infant relationship.

CONCLUSION

The findings from this study offer ways for midwives to support the emerging mother-infant relationship during the early postnatal period. Facilitating mothers to engage with their baby as well as integrating key people is important. Midwives also play a key role in building maternal confidence and competence. Further research is needed to embed and evaluate strategies in midwifery practice.

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.

The potential role of robust face representations learned within families when searching for one's child in a crowd

Own child's face is one of the most socially salient stimuli for parents, and a faster search for it than for other children's faces may help provide warmer and more sensitive care. However, it has not been experimentally examined whether parents find their child's face faster. In addition, although own child's face is specially processed, the search time for own child's face may be similar to that for other socially salient stimuli, such as own or spouse's faces. This study tested these possibilities using a visual search paradigm. Participants (parents) searched for their child's, own, spouse's, other child's, same-sex adult's, or opposite-sex adult's faces as search targets. Our findings indicate that both mothers and fathers identified their child's face more quickly than other children's faces. Similarly, parents found their own and spouse's faces more quickly than other adults' faces. Moreover, the search time for family members' faces increased with the number of faces on the search display, suggesting an attentional serial search. These results suggest that robust face representations learned within families and close relationships can support reduced search times for family members' faces.

Affective cognition in response to infant stimuli in pregnant compared with non-pregnant women

Physiological, neurocognitive, and psychological changes facilitates adaptation to motherhood. This cross-sectional study aimed to examine differences between pregnant and non-pregnant women in affective cognitive and psychophysiological responses to infant stimuli. We hypothesized that pregnant women would display (I) reduced negative emotional reactivity and perception of distressed infant stimuli, (II) increased attention toward infants compared to adults, and (III) greater psychophysiological response to infant distress. The sample comprised 22 pregnant women (22-38 weeks gestation) and 18 non-pregnant nulliparous women. Four computerized tasks were administered to measure affective cognitive processing of infant stimuli, while recording facial expressions, electrodermal activity, and eye gazes. Results indicated that pregnant women exhibited fewer negative facial expressions, reported less frustration when exposed to distressed infant cries, and showed greater attention to emotional infant faces compared to non-pregnant women, but the differences did not remain statistically significant after correction for multiple comparisons. No differences were observed in psychophysiological responses. The findings indicate a possible pregnancy-mediated effect regarding the cognitive processing of infant stimuli, potentially as preparation for motherhood. Future research with larger samples and longitudinal design is needed to understand the predictors, timing, and plasticity of cognitive changes during pregnancy.

Cannabis use during pregnancy and hemodynamic responses to infant cues in pregnancy: an exploratory study

Introduction

Cannabis is one of the most commonly used substances during pregnancy and has the potential to negatively impact parent-infant relationships. The prefrontal cortex (PFC) response to infant cues during pregnancy has been associated with subsequent positive parenting behaviors. However, PFC activation is altered in individuals who use cannabis. As the potency of cannabis has changed over the years, little is known about the specific role of cannabis use on gestational parent brain responses to infant cues.

Materials and methods

Using functional Near-Infrared Spectroscopy (fNIRS) in the second trimester of pregnancy, we measured hemodynamic responses to an infant cry task and an infant faces task among individuals who were using cannabis (N = 14) and compared them with those who were not using cannabis (N = 45). For the infant cry task, pregnant individuals listened to cry sounds and matched white noise. For the infant faces task, they viewed happy, sad, and neutral faces.

Results

There was no significant difference between the two groups after adjusting for multiple comparisons. Without adjusting for multiple comparisons, we found preliminary evidence for the differences in the dorsomedial PFC associated with heightened response to infant cry among individuals who use cannabis. The groups were also different in the dorsolateral PFC associated with decreased response to infant sad faces among individuals who use cannabis.

Discussion

Our preliminary data suggests that cannabis use during pregnancy was associated with brain activation in the regions involved in the emotional regulation and information processes. However, the results did not survive after adjustment for multiple comparisons, thus future research with larger sample sizes is needed to confirm potential differences in brain function among cannabis-using pregnant individuals.

Prediction of postpartum depression with an online neurocognitive risk screening tool for pregnant women

Postpartum depression (PPD) is a severe mental illness affecting 10-15% of mothers. Emerging evidence indicates that negative neurocognitive bias in response to infant distress during pregnancy marks an increased risk of PPD. This proof-of-concept study aimed to investigate the association between negatively biased neurocognitive processing of infant distress during pregnancy and subsequent PPD and to explore the feasibility of an online risk screening tool. In the second or third trimester of pregnancy, 87 participants underwent two online tests of reactivity to and evaluation of infant distress and completed questionnaires regarding psychosocial risk factors. After birth, participants rated their depressive symptoms online and underwent a diagnostic telephone interview concerning PPD. Irrespective of depressive symptoms during pregnancy, negative reactivity to and evaluation of infant distress predicted PPD (reactivity: Exp(B)=1.33, p = 0.04) and depressive symptoms after birth (reactivity: B = 0.04, p = 0.048; evaluation: B = 0.10, p = 0.04). The negative reactivity toward infant distress showed high sensitivity and moderate specificity (89% and 77%, respectively), while the evaluation of infant distressed cries showed lower sensitivity and specificity (67% and 66%, respectively). The relatively small sample size prevented the inclusion of additional risk variables in the regression models. The replication of an association between negative neurocognitive bias during pregnancy with PPD risk is noteworthy and has clinical implications in terms of early prevention. However, the low response rate indicates that this tool is not feasible in its current form. Future larger-scale studies are needed to further investigate candidate risk factors in a brief online screening tool.

The significance of mothers' attachment representations for vagal responding during interactions with infants

Little is known about the significance of mothers' attachment for neurobiological responding during interactions with infants. To address this gap, this study examined links between mothers' (N = 139) attachment representations and dynamic change in respiratory sinus arrhythmia (RSA) while interacting with infants in the Still-Face Procedure (SFP). Mothers higher on secure base script knowledge (SBSK) exhibited greater RSA reactivity during the SFP characterized by lower RSA during normal play, higher RSA during the still-face, and lower RSA during reunion. Findings indicate that mothers higher on SBSK exhibit RSA responding expected to support active behavioral coping during normal play and reunion - consistent with the need to engage infants in social interaction - and RSA responding during the still-face expected to support efforts to calm the body and empathize with their infant during this distressing social disruption. Findings advance knowledge of the significance of adult attachment for the neurobiology of caregiving.

Racial disparities in EEG research and their implications for our understanding of the maternal brain

Racial disparities in maternal health are alarming and persistent. Use of electroencephalography (EEG) and event-related potentials (ERPs) to understand the maternal brain can improve our knowledge of maternal health by providing insight into mechanisms underlying maternal well-being, including implications for child development. However, systematic racial bias exists in EEG methodology-particularly for Black individuals-and in psychological and health research broadly. This paper discusses these biases in the context of EEG/ERP research on the maternal brain. First, we assess the racial/ethnic diversity of existing ERP studies of maternal neural responding to infant/child emotional expressions, using papers from a recent meta-analysis, finding that the majority of mothers represented in this research are of White/European ancestry and that the racially and ethnically diverse samples that are present are limited in terms of geography. Therefore, our current knowledge base in this area may be biased and not generalizable across racially diverse mothers. We outline factors underlying this problem, beginning with the racial bias in EEG equipment that systematically excludes individuals of African descent, and also considering factors specific to research with mothers. Finally, we highlight recent innovations to EEG hardware to better accommodate diverse hairstyles and textures, and other important steps to increase racial and ethnic representativeness in EEG/ERP research with mothers. We urge EEG/ERP researchers who study the maternal brain-including our own research group-to take action to increase racial diversity so that this research area can confidently inform understanding of maternal health and contribute to minimizing maternal health disparities.

Processing children's faces in the parental brain: A meta-analysis of ERP studies

Event-related potentials (ERPs) are an excellent tool for investigating parental neural responses to child stimuli. Using meta-analysis, we quantified the results of available studies reporting N170 or LPP/P3 ERP responses to children's faces, targeting three questions: 1) Do parents and non-parents differ in ERP responses to child faces? 2) Are parental ERP responses larger to own vs. unfamiliar child faces? 3) Are parental ERP responses to child faces associated with indicators of parenting quality, such as observed parental sensitivity? Across 23 studies (N = 1035), key findings showed 1) larger N170 amplitudes to child faces in parents than in non-parents (r = 0.19), 2) larger LPP/P3 responses to own vs. unfamiliar child faces in parents (r = 0.19), and 3) positive associations between parental LPP/P3 responses to child faces and parenting quality outcomes (r = 0.15). These results encourage further research particularly with the LPP/P3 to assess attentional-motivational processes of parenting, but also highlight the need for larger samples and more systematic assessments of associations between ERPs and parenting.

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.

Emerging biomarkers for child & family intervention studies: A review of EEG studies of parenting

Most interventions for childhood mental health problems require significant parental involvement, and treatment programs are increasingly incorporating components aimed at enhancing parents' own self-regulation in the context of potentially stressful parent-child interactions. This paper discusses the promise of EEG in examining the rapidly unfolding perceptual, cognitive, emotional, and regulatory processes that occur in parenting, in hopes of ultimately informing child and family interventions. First, we review two separate bodies of work that have used EEG with parents: one examining event-related potential (ERP) measures, and the other examining frontal alpha asymmetry (FAA). We discuss benefits of each within the study of parenting, and also suggest other EEG metrics (such as event-related time-frequency analyses) that can be leveraged to fill current gaps in our knowledge. Finally, we discuss the potential for these findings to inform clinical work with children and families, such as identifying biomarkers that could aid in assessment, treatment recommendations, and monitoring response to interventions.

Infants' neutral facial expressions elicit the strongest initial attentional bias in adults: Behavioral and electrophysiological evidence

Recent studies that used adult faces as the baseline have revealed that attentional bias toward infant faces is the strongest for neutral expressions than for happy and sad expressions. However, the time course of the strongest attentional bias toward infant neutral expressions is unclear. To clarify this time course, we combined a behavioral dot-probe task with electrophysiological event-related potentials (ERPs) to measure adults' responses to infant and adult faces with happy, neutral, and sad expressions derived from the same face. The results indicated that compared with the corresponding expressions in adult faces, attentional bias toward infant faces with various expressions resulted in different patterns during rapid and prolonged attention stages. In particular, first, neutral expressions in infant faces elicited greater behavioral attentional bias and P1 responses than happy and sad ones did. Second, sad expressions in infant faces elicited greater N170 responses than neutral and happy ones did; notably, sad expressions elicited greater N170 responses in the left hemisphere in women than in men. Third, late positive potential (LPP) responses were greater for infant faces than for adult faces under each expression condition. Thus, we propose a three-stage model of attentional allocation patterns that reveals the time course of attentional bias toward infant faces with various expressions. This model highlights the prominent role of neutral facial expressions in the attentional bias toward infant faces.

The rewards of motherhood: Neural response to reward in pregnancy prospectively predicts maternal bonding with the infant in the postpartum period

Mother-to-infant attachment is critical to the health of mothers and offspring. While reward circuitry is implicated in maternal attachment, no studies have yet examined whether antenatal (i.e., in pregnancy) reward responsiveness predicts mother-to-infant bonding in the postnatal period. In a sample of 63 women, we examined whether the Reward Positivity (RewP), an event-related potential elicited to feedback indicating monetary reward, measured in pregnancy prospectively predicts self-reported mother-to-infant attachment at approximately one year postpartum. An increased antenatal RewP was associated with increased postnatal pleasure in proximity with the infant. Furthermore, this association was independent of associations with depression, anxiety, and stress symptoms. This is the first study to find a prospective association between reward responsiveness in pregnancy and postnatal bonding with the infant. Future directions for attachment research are discussed.

Using Co-design to Explore How Midwives Can Support the Emerging Mother-Infant Relationship During the Early Postnatal Period: Protocol for a Mixed Methods Study

BACKGROUND

The postnatal period can be a challenging time for women, with mothers experiencing a range of emotions. As a woman transitions to motherhood, she adjusts to a new sense of self and forms a new relationship with her infant. Becoming a mother is a complex cognitive and social process that is unique for each woman and is influenced and shaped by culture. The emerging mother-infant relationship is a significant factor in maternal well-being and infant development, with the bond between the mother and her baby being critical to the development of secure attachment. It has been recognized that the strength of this relationship is the main predictor of how well a child will do throughout life. There has been a global focus on the importance of the first 1000 days, with Australia identifying this as a national priority. Midwives are ideally placed to support mothers during the development of the mother-infant relationship, providing care through the early postnatal period, which has been identified as a sensitive period for the development of the mother-infant relationship.

OBJECTIVE

The aim of this study is to explore how midwives can support the emerging mother-infant relationship in the context of cultural diversity and develop an appropriate co-designed intervention in the early postnatal period.

METHODS

This study will use a mixed method approach, specifically the exploratory sequential design (intervention development variant). This study will be undertaken in 3 phases: 1 qualitative phase, which is followed by 2 quantitative phases. Phase 1 will include a scoping review to explore interventions that have influenced the development of the mother-infant relationship, and then, interviews will be undertaken with women exploring their early experiences of motherhood, followed by 3 co-design workshops. The workshops will engage with multilevel stakeholder representatives where, through partnership and participation, they will propose and develop an intervention to support the emerging mother-infant relationship. Phase 2 will develop and pilot 2 purpose-designed evaluation surveys to evaluate the co-designed intervention from the perspective of both mothers and midwives. Phase 3 will implement and evaluate the co-designed intervention using pre- and postmeasures and feedback from the purpose-designed surveys.

RESULTS

Phase 1 has commenced and is expected to be completed by August 2021. Phase 2 is expected to be completed by September 2021, with phase 3 commencing in October 2021. The study will be completed by March 2023.

CONCLUSIONS

The results of this study will be shared with a variety of audiences and will contribute to the body of knowledge on the mother-infant relationship, potentially improving the understanding of this relationship for women and midwives. This may result in improved strategies for care, with mothers benefiting from enhanced experience and satisfaction during the early postnatal period.

Neurocognitive processing of infant stimuli in mothers and non-mothers: psychophysiological, cognitive and neuroimaging evidence

Emerging evidence indicates that mothers and non-mothers show different neurocognitive responses to infant stimuli. This study investigated mothers' psychophysiological, cognitive and neuronal responses to emotional infant stimuli. A total of 35 mothers with 4-month-old infants and 18 control women without young children underwent computerized tests assessing neurocognitive processing of infant stimuli. Their eye gazes and eye fixations, galvanic skin responses (GSRs) and facial expressions towards infant emotional stimuli were recorded during the tasks. Participants underwent functional magnetic resonance imaging during which they viewed pictures of an unknown infant and, for mothers, their own infants. Mothers gazed more and had increased GSR towards infant stimuli and displayed more positive facial expressions to infant laughter, and self-reported more positive ratings of infant vocalizations than control women. At a neural level, mothers showed greater neural response in insula, dorsolateral prefrontal cortex and occipital brain regions within a predefined 'maternal neural network' while watching images of their own vs unknown infants. This specific neural response to own infants correlated with less negative ratings of own vs unknown infants' signals of distress. Differences between mothers and control women without young children could be interpreted as neurocognitive adaptation to motherhood in the mothers.

How stress can influence brain adaptations to motherhood

Research shows that a woman's brain and body undergo drastic changes to support her transition to parenthood during the perinatal period. The presence of this plasticity suggests that mothers' brains may be changed by their experiences. Exposure to severe stress may disrupt adaptive changes in the maternal brain and further impact the neural circuits of stress regulation and maternal motivation. Emerging literature of human mothers provides evidence that stressful experience, whether from the past or present environment, is associated with altered responses to infant cues in brain circuits that support maternal motivation, emotion regulation, and empathy. Interventions that reduce stress levels in mothers may reverse the negative impact of stress exposure on the maternal brain. Finally, outstanding questions regarding the timing, chronicity, types, and severity of stress exposure, as well as study design to identify the causal impact of stress, and the role of race/ethnicity are discussed.

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.

Correlates of prenatal and postnatal mother-to-infant bonding quality: A systematic review

BACKGROUND

Mother-to-infant bonding is defined as the emotional tie experienced by a mother towards her child, which is considered to be important for the socio-emotional development of the child. Numerous studies on the correlates of both prenatal and postnatal mother-to-infant bonding quality have been published over the last decades. An up-to-date systematic review of these correlates is lacking, however.

OBJECTIVE

To systematically review correlates of prenatal and postnatal mother-to-infant bonding quality in the general population, in order to enable targeted interventions.

METHODS

MEDLINE, Embase, CINAHL, and PsychINFO were searched through May 2018. Reference checks were performed. Case-control, cross-sectional or longitudinal cohort studies written in English, German, Swedish, Spanish, Norwegian, French or Dutch defining mother-to-infant bonding quality as stipulated in the protocol (PROSPERO CRD42016040183) were included. Two investigators independently reviewed abstracts, full-text articles and extracted data. Methodological quality was assessed using the National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-sectional studies and was rated accordingly as poor, fair or good. Clinical and methodological heterogeneity were examined.

MAIN RESULTS

131 studies were included. Quality was fair for 20 studies, and poor for 111 studies. Among 123 correlates identified, 3 were consistently associated with mother-to-infant bonding quality: 1) duration of gestation at assessment was positively associated with prenatal bonding quality, 2) depressive symptoms were negatively associated with postnatal mother-to-infant bonding quality, and 3) mother-to-infant bonding quality earlier in pregnancy or postpartum was positively associated with mother-to-infant bonding quality later in time.

CONCLUSION

Our review suggests that professionals involved in maternal health care should consider monitoring mother-to-infant bonding already during pregnancy. Future research should evaluate whether interventions aimed at depressive symptoms help to promote mother-to-infant bonding quality. More high-quality research on correlates for which inconsistent results were found is needed.