Infants' neural sensitivity to social interactions varies by income and infant-directed speech.

Social interactions are essential for infant brain development, yet we know little about how infant functional connectivity differs between social and nonsocial contexts, or how sensitivity to differences between contexts might be related to early distal and proximal environmental factors. We compared 12-month-old infants' intrahemispheric electroencephalographic (EEG) coherence between a social and a nonsocial condition, then examined whether differences between conditions varied as a function of family economic strain and two maternal behaviors at 6 months, positive affect and infant-directed speech. We found lower EEG coherence from the frontal region to the central, parietal, temporal, and occipital regions during the social condition, but only for infants from higher-income families and infants whose mothers used higher proportions of infant-directed speech. In contrast, there were no differences between social and nonsocial conditions for infants from economically strained families or infants whose mothers used lower proportions of infant-directed speech. This study demonstrates that neural organization differs between a nonsocial baseline and a social interaction, but said differentiation is not present for infants from less privileged backgrounds. Our results underscore the importance of examining brain activity during species-typical contexts to understand the role of environmental factors in brain development.

Social Fear in US Infants: The Roles of Hair and Salivary Cortisol.

Elevated social fear in infancy poses risk for later social maladjustment and psychopathology. Hair cortisol concentration (HCC), an index of cumulative cortisol exposure, and diurnal salivary cortisol slope, a biomarker of acute stress regulation, have been associated with social fear behaviors in childhood; however, no research has addressed their relations in infancy. Elucidating potential biomarkers of infant social fear behaviors, as well as environmental factors associated with these biomarkers, may grant insights into the ontogeny of fear behaviors that increase risk for internalizing and externalizing psychopathologies later in life. The current study used multiple linear regression to examine if infant HCC, infant diurnal cortisol slope, and income-to-needs ratios (ITN) were differentially associated with observed social fear responses to a Stranger Approach task at 12 months. Using a sample of 90 infants (Mage = 12.26m, SD = 0.81m, 50% female), results indicated that increased infant HCC was associated with increased distress vocalizations during the Stranger Approach task, while steeper diurnal cortisol slope was associated with fewer distress vocalizations. Ordinary least squares path analyses did not reveal group differences between economically strained and non-strained infants in how cortisol measures and social fear responses related. Findings underscore very early psychobiological correlates of fearfulness that may increase risk for fear-related disorders and adverse mental health symptomology across childhood.

Infant diurnal cortisol predicts sleep.

The sleep-wake system is immature at birth and develops in parallel with the hypothalamic-pituitary-adrenal axis, a biological stress system of which the end product is cortisol. Perturbations in one system during infancy can maladaptively influence the maturation of the other system, leading to lasting sleep and cortisol system dysregulation and heightening the risk of enduring health problems. To better understand the early interplay between these systems, we examined whether actigraphy-derived measures of night-time sleep duration and onset were associated with cumulative exposure to cortisol, indexed by hair cortisol concentration, in 12-month-old children. Overall, early sleep onset predicted lower hair cortisol above and beyond sleep duration, family income and chaos experienced at home. Furthermore, both sleep and cortisol levels vary day to day, and temporal dependencies between daily sleep and cortisol regulation are not well understood. Thus, we assessed how the sleep characteristics on a particular evening related to salivary cortisol levels the following day and how daytime and evening cortisol related to the sleep characteristics on the same night. Lower total exposure to cortisol on a particular day was related to longer night-time sleep duration the same night, but not sleep onset. Lower salivary cortisol levels on a given evening related to earlier sleep onset the same night, but not to night-time sleep duration. Sleep duration and onset on a given night were unrelated to total cortisol exposure the following day. Findings suggest that in early development, the day-to-day relation between sleep and cortisol is not bidirectional, but more driven by diurnal cortisol.

Cortisol and socioeconomic status in early childhood: A multidimensional assessment.

The hypothalamic-pituitary-adrenal (HPA) axis is sensitive to early life stress, with enduring consequences for biological stress vulnerability and health (Gunnar & Talge, 2008). Low socioeconomic status (SES) is associated with dysregulation of the stress hormone cortisol in early childhood. However, a mechanistic understanding of this association is lacking. Multidimensional assessment of both SES and cortisol is needed to characterize the intricate relations between SES and cortisol function in early childhood. We assessed parent-reported family income, parent education, occupational prestige, neighborhood risk, food insecurity, and household chaos for 12-month-old infants (N = 90) and 3.5-year-old children (N = 91). Hair cortisol concentration (HCC) was obtained from parent and child, indexing chronic biological stress, and diurnal salivary cortisol was measured in the children. Controlling for parent HCC, parent education uniquely predicted infant and child HCC and, in addition, neighborhood risk uniquely predicted infant HCC. Household chaos predicted bedtime salivary cortisol concentration (SCC) for both infants and children, and infant daily cortisol output. Food insecurity was associated with flattened cortisol slope in 3.5-year-old children. Parental sensitivity did not mediate relations between SES and cortisol. Results highlight the utility of SES measures that index unpredictable and unsafe contexts, such as neighborhood risk, food insecurity, and household chaos.

A systematic assessment of socioeconomic status and executive functioning in early childhood.

Lower socioeconomic status (SES) consistently relates to poorer executive function (EF). This study used a systematic and nuanced approach to understand how SES relates to children's EF at a process level. We assessed children aged 4.5-5.5 years. This is a key developmental period because EF is no longer a unitary construct but rather EF components statistically load on separate factors and index distinct aspects of EF. Children completed a working memory task that involved a cognitive load component and a go/no-go task to assess inhibitory control and vigilance. Accuracy and reaction time were assessed, and each task involved four blocks to assess performance over time. Lower SES related to lower accuracy for working memory, inhibitory control, and vigilance as well as slower reaction time for working memory. SES did not relate to go/no-go reaction time. For working memory, lower SES related to poorer accuracy on lower cognitive load trials, but there were no SES differences on higher cognitive load trials. SES did not relate to maintenance of performance over time. Results suggest that for this age group the majority of domains showed SES differences. However, there were no SES differences in performance for remembering two items and maintaining performance. Thus, although overall lower SES related to poorer EF performance, there were no SES effects for skills that are still emerging for all children, namely, maintaining task performance across time and remembering two items at once. Results highlight the importance of assessing EF as a multidimensional construct and may help to identify targets for intervention.

Emotion regulation moderates the association between parent and child hair cortisol concentrations.

Successful emotion regulation facilitates children's coping with everyday stress. It develops rapidly in the early preschool period. However, no work has been done to investigate the potential buffering role of emotion regulation from cumulative physiological effects of stress. In this study, we examined hair cortisol concentration (HCC), an early marker of chronic physiological stress, socioeconomic status (SES), parental sensitivity, and emotion regulation and reactivity in a sample of 3.5-year-old children (N = 86). Emotion regulation and emotional reactivity were independent of child HCC. However, emotion regulation moderated the relationship between parent and child HCC. For children with better emotion regulation, there was no association between parent and child HCC, suggesting that emotion regulation skills buffered the transgenerational effects of chronic physiological stress. Emotional reactivity moderated the relationship between SES and child HCC, and attenuated the association between parental sensitivity and child HCC. Taken together, these findings demonstrate that children who were less emotionally reactive were less susceptible to their environments. Results provide support that child emotion regulation and emotional reactivity can reduce or strengthen the relationship between established risk factors and levels of chronic physiological stress in early childhood.

Salivary cortisol reactivity in preschoolers is associated with hair cortisol and behavioral problems.

The interplay between children's cortisol reactivity to challenge and cumulative cortisol exposure is not well understood. Examining the role of cortisol reactivity in early childhood may elucidate biological mechanisms that contribute to children's chronic physiological stress and behavioral dysregulation. In a sample of 65 preschool-aged children, we examined the relation between children's salivary cortisol reactivity to challenging tasks and their hair cortisol concentration (HCC). While both are biomarkers of the hypothalamic-pituitary-adrenal (HPA) axis, salivary cortisol reactivity reflects an acute cortisol response to a stressor and HCC reflects cumulative cortisol exposure. In addition, we examined the relations of these stress biomarkers with internalizing and externalizing problems. Salivary cortisol reactivity was associated with higher HCC and with increased externalizing behaviors. Child HCC also was positively correlated with parent HCC. Results highlight the contributions of salivary cortisol reactivity to children's cumulative cortisol exposure, which may add to their biological risk for health problems later. The observed association between externalizing problems and salivary cortisol reactivity indicates concordances between dysregulated behavioral reactions and dysregulated cortisol responses to challenges. The finding that salivary cortisol reactivity to challenge in early childhood plays a role in children's cumulative cortisol exposure and behavioral development suggests pathways through which cortisol reactivity may influence long-term physical and mental health.

Maternal cortisol slope at 6 months predicts infant cortisol slope and EEG power at 12 months.

Physiological stress systems and the brain rapidly develop through infancy. While the roles of caregiving and environmental factors have been studied, implications of maternal physiological stress are unclear. We assessed maternal and infant diurnal cortisol when infants were 6 and 12 months. We measured 12-month infant electroencephalography (EEG) 6-9 Hz power during a social interaction. Steeper 6-month maternal slope predicted steeper 12-month infant slope controlling for 6-month infant slope and breastfeeding. Steeper 6-month maternal slope predicted lower 6-9 Hz power. Six-month maternal area under the cuve (AUCg) was unrelated to 12-month infant AUCg and 6-9 Hz power. Psychosocial, caregiving, and breastfeeding variables did not explain results. At 6 months, maternal and infant slopes correlated, as did maternal and infant AUCg. Twelve-month maternal and infant cortisol were unrelated. Results indicate maternal slope is an informative predictor of infant physiology and suggest the importance of maternal physiological stress in this developmental period.

Infant hair cortisol: associations with salivary cortisol and environmental context.

Early chronic stress has enduring implications for physical and mental health outcomes. Hair cortisol concentration (HCC) has emerged as a marker of cumulative cortisol exposure, yet HCC in infants is not well understood. We examined how infant HCC relates to widely used basal salivary cortisol measures, maternal HCC, and environmental context in 111 infants assessed at 6 and 12 months of age. Maternal HCC at 6 and 12 months was correlated with infant HCC at 12 months. At 12 months, infant HCC was positively associated with waking salivary cortisol concentration (SCC), evening SCC, and area under the curve (AUC), but was independent of diurnal slope. Breastfeeding was associated with lower HCC, whereas increased sleep disruption was related to flatter slope. Reduced nighttime sleep duration was related both to higher HCC and to flatter slope. A person-focused analysis indicated that the combination of high HCC and flattened slope was associated with more environmental risks, highlighting the importance of investigating the interplay between HCC and diurnal cortisol slope. Results support the validity of HCC as a marker of cumulative cortisol exposure in infancy, while emphasizing the value of including multiple cortisol measures assessing distinct aspects of hypothalamic-pituitary-adrenal (HPA) function.

Emotion understanding, parent mental state language, and behavior problems in internationally adopted children.

Internationally adopted postinstitutionalized (PI) children are at risk for lower levels of emotion understanding. This study examined how postadoption parenting influences emotion understanding and whether lower levels of emotion understanding are associated with behavior problems. Emotion understanding and parent mental state language were assessed in 3-year-old internationally adopted PI children (N = 25), and comparison groups of children internationally adopted from foster care (N = 25) and nonadopted (NA) children (N = 36). At 5.5-year follow-up, PI children had lower levels of emotion understanding than NA children, a group difference not explained by language. In the total sample, parent mental state language at age 3 years predicted 5.5-year emotion understanding after controlling for child language ability. The association of parent mental state language and 5.5-year emotion understanding was moderated by adoption status, such that parent mental state language predicted 5.5-year emotion understanding for the internationally adopted children, but not for the NA children. While postadoption experience does not erase negative effects of early deprivation on emotion understanding, results suggest that parents can promote emotion understanding development through mental state talk. At 5.5 years, PI children had more internalizing and externalizing problems than NA children, and these behavioral problems related to lower levels of emotion understanding.

Variation in infant EEG power across social and nonsocial contexts.

To understand the infant social brain, it is critical to observe functional neural activation during social interaction. Yet many infant electroencephalography (EEG) studies on socioemotional development have recorded neural activity only during a baseline state. This study investigated how infant EEG power (4-6Hz and 6-9Hz) varies across social and nonsocial contexts. EEG was recorded in 12-month-olds across controlled conditions to disentangle the neural bases of social interactions. Four conditions-nonsocial, joint attention, language-only, and social engagement-were designed to tease apart how different environmental inputs relate to infant EEG power. We analyzed EEG power in frontal, central, temporal, and parietal regions. During the joint attention condition compared with the other conditions, 4-6Hz frontal, central, and parietal power was lowest, indexing greater neural activation. There was lower 4-6Hz and 6-9Hz power in the temporal region in both the joint attention and social engagement conditions compared with the nonsocial condition. In 6-9Hz, the pattern was consistent with 4-6Hz findings for the frontal region such that 6-9Hz frontal power was lower, indexing greater neural activation, in the joint attention condition compared with the nonsocial condition. There were no differences between conditions in central and parietal regions in 6-9Hz. Findings highlight the methodological importance of recording functional brain activity in multiple controlled contexts to explicate the neural bases of the infant social brain.

Neonatal eyelid conditioning during sleep.

Using an eyelid conditioning paradigm modeled after that developed by Little, Lipsitt, and Rovee-Collier (1984), Fifer et al. (2010) demonstrated that newborn infants learn during sleep. This study examined the role of sleep state in neonatal learning. We recorded electroencephalogram (EEG), respiratory, and cardiovascular activity from sleeping full term newborn infants during delay eyelid conditioning. In the experimental group (n = 21), a tone was paired with an air puff to the eye. Consistent with Fifer et al. (2010), newborn infants reliably learned during sleep. The experimental group more than doubled EMR rates to a tone alone, while a control group (n = 17) presented with unpaired tones and puffs maintained low EMR rates. Infant learners were more likely to produce a conditioned EMR during quiet sleep compared to active sleep. Understanding the influence of sleep state on conditioned responses will inform the potential use of eyelid conditioning for early screening.

Neonatal Physical Growth Predicts Electroencephalography Power in Rural South African Children.

Anthropometric measures at birth, indexing prenatal growth, are associated with later cognitive development. Children in low- and middle-income countries (LMIC) are at elevated risk for impaired prenatal and early postnatal growth and enduring cognitive deficits. However, the associations of neonatal physical growth with neural activity are not well-characterized in LMIC contexts, given the dearth of early childhood neuroimaging research in these settings. The current study examined birth length, weight, and head circumference as predictors of EEG relative power over the first three years of life in rural Limpopo Province, South Africa, controlling for postnatal growth and socioeconomic status (SES). A larger head circumference at birth predicted lower relative gamma power, lower right hemisphere relative beta power, and higher relative alpha and theta power. A greater birth length also predicted lower relative gamma power. There were interactions with timepoints such that the associations of birth head circumference and length with EEG power were most pronounced at the 7-month assessment and were attenuated at the 17- and 36-month assessments. The results identify birth head circumference and length as specific predictors of infant neural activity within an under-resourced context.

The development and diversity of religious cognition and behavior: Protocol for Wave 1 data collection with children and parents by the Developing Belief Network.

The Developing Belief Network is a consortium of researchers studying human development in diverse social-cultural settings, with a focus on the interplay between general cognitive development and culturally specific processes of socialization and cultural transmission in early and middle childhood. The current manuscript describes the study protocol for the network's first wave of data collection, which aims to explore the development and diversity of religious cognition and behavior. This work is guided by three key research questions: (1) How do children represent and reason about religious and supernatural agents? (2) How do children represent and reason about religion as an aspect of social identity? (3) How are religious and supernatural beliefs transmitted within and between generations? The protocol is designed to address these questions via a set of nine tasks for children between the ages of 4 and 10 years, a comprehensive survey completed by their parents/caregivers, and a task designed to elicit conversations between children and caregivers. This study is being conducted in 39 distinct cultural-religious groups (to date), spanning 17 countries and 13 languages. In this manuscript, we provide detailed descriptions of all elements of this study protocol, give a brief overview of the ways in which this protocol has been adapted for use in diverse religious communities, and present the final, English-language study materials for 6 of the 39 cultural-religious groups who are currently being recruited for this study: Protestant Americans, Catholic Americans, American members of the Church of Jesus Christ of Latter-day Saints, Jewish Americans, Muslim Americans, and religiously unaffiliated Americans.

Newborn infants learn during sleep.

Newborn infants must rapidly adjust their physiology and behavior to the specific demands of the novel postnatal environment. This adaptation depends, at least in part, on the infant's ability to learn from experiences. We report here that infants exhibit learning even while asleep. Bioelectrical activity from face and scalp electrodes was recorded from neonates during an eye movement conditioning procedure in which a tone was followed by a puff of air to the eye. Sleeping newborns rapidly learned the predictive relationship between the tone and the puff. Additionally, in the latter part of training, these infants exhibited a frontally maximum positive EEG slow wave possibly reflecting memory updating. As newborns spend most of their time sleeping, the ability to learn about external stimuli in the postnatal environment during nonawake states may be crucial for rapid adaptation and infant survival. Furthermore, because eyelid conditioning reflects functional cerebellar circuitry, this method potentially offers a unique approach for early identification of infants at risk for a range of developmental disorders including autism and dyslexia.

Perceptions of HIV and Mental Illness as "Western" or "Traditional" Illnesses: A Cross-Sectional Study from Limpopo Province, South Africa.

Although Western biomedical treatment has dramatically increased across sub-Saharan African health systems, traditional medicine as a form of healing and beliefs in supernatural powers as explanations for disease remain prevalent. Research in this region has identified HIV in particular as a disease located within both the traditional African and Western medical paradigms, whilst mental illness is ascribed to primarily supernatural causes. Within this context, this study sought to understand and explore the perceptions of HIV and mental illness among a population of rural women in Limpopo, South Africa. 82 in-depth interviews were conducted between January and December, 2022. Interviews were transcribed and translated into English. Data were managed using NVivo 11 software and thematically analyzed. The majority of participants identified HIV as a Western illness requiring biomedical treatment with causation largely attributed to biological mechanisms. A traditional form of HIV only cured using traditional treatments was also denoted. Unlike for HIV, the majority of respondents felt that there was no biological or behavioral cause for mental illness but rather the illness was conceptualized supernaturally thus likely impacting patient care pathways. Further research to study HIV and mental health perceptions among a larger sample in different regions of sub-Saharan Africa is warranted.

Vaccination coverage at seven months of age in Limpopo Province, South Africa: a cross-sectional survey.

Many low- and middle-income countries face challenges in attaining adequate levels of vaccination coverage, and the factors driving this under-coverage have not been completely elucidated. In this cross-sectional study, we investigated factors associated with vaccination coverage in Mopani District, Limpopo Province, South Africa. Between July and October 2017, we surveyed 317 caregivers (83% of whom were mothers) of seven-month-old infants in Mopani District about barriers faced when attaining vaccines and attitudes towards vaccination, and reviewed the infants' documented vaccination history. Caregiver and child demographic data were collected shortly after birth. We described the coverage for vaccines that should be received by age seven months, according to South Africa's Expanded Programme on Immunization schedule, and explored the relationship between coverage and caregiver characteristics, behavioral factors (e.g. attitudes towards vaccination), and structural factors (e.g. vaccination stock-outs at clinics). We found that caregivers reported positive attitudes towards vaccination, based on a seven-question survey of vaccination attitudes. Although coverage was high for most recommended vaccines, it was low for pneumococcal conjugate vaccine (PCV), with just 36% of children having received it by age seven months. This appears to have been due to PCV stock-outs at government clinics. For vaccines other than PCV, children were more likely to be up-to-date on vaccinations if a community health worker (CHW) had visited their home in the past month (adjusted odds ratio (OR) 1.24, confidence interval (CI) (1.10-1.41); p < 0.001) and if the caregiver had more years of schooling (adjusted OR 1.03 (CI 1.01-1.05); p = 0.012). We conclude that addressing PCV stock-outs at government clinics in Mopani District is necessary to ensure coverage reaches adequate levels. Additionally, supporting CHW programs may be a productive avenue for improving vaccination coverage.

Toward an electrocortical biomarker of cognition for newborn infants.

The event-related potential (ERP) effect of mismatch negativity (MMN) was the first electrophysiological probe to evaluate cognitive processing (change detection) in newborn infants. Initial studies of MMN predicted clinical utility for this measure in identification of infants at risk for developmental cognitive deficits. These predictions have not been realized. We hypothesized that in sleeping newborn infants, measures derived from wavelet assessment of power in the MMN paradigm would be more robust markers of the brain's response to stimulus change than the ERP-derived MMN. Consistent with this premise, we found increased power in response to unpredictable and infrequent tones compared to frequent tones. These increases were present at multiple locations on the scalp over a range of latencies and frequencies and occurred even in the absence of an ERP-derived MMN. There were two predominant effects. First, theta band power was elevated at middle and late latencies (200 to 600 ms), suggesting that neocortical theta rhythms that subserve working memory in adults are present at birth. Second, late latency (500 ms) increased power to the unpredictable and infrequent tones was observed in the beta and gamma bands, suggesting that oscillations involved in adult cognition are also present in the neonate. These findings support the expectation that frequency dependent measures, such as wavelet power, will improve the prospects for a clinically useful test of cortical function early in the postnatal period.

Postadoption parenting and socioemotional development in postinstitutionalized children.

Children adopted from institutions (e.g., orphanages) overseas are at increased risk of disturbances in social relationships and social understanding. Not all postinstitutionalized children exhibit these problems, although factors like the severity of deprivation and duration of deprivation increase their risk. To date, few studies have examined whether postadoption parenting might moderate the impact of early adverse care. Three groups were studied: postinstitutionalized and foster care children both adopted internationally and nonadopted children reared in their families of origin. The Emotional Availability (EA) Scales were assessed at 18 months in parent-child dyads. Parent emotional availability was found to predict two aspects of social functioning shown in previous studies to be impaired in postinstitutionalized children. Specifically, EA positively correlated with emotion understanding at 36 months; in interaction with initiation of joint attention at 18 months and group, it predicted indiscriminate friendliness as scored from a parent attachment interview at 30 months. Among the postinstitutionalized children but not among the children in other groups, higher EA scores reduced the negative association between initiation of joint attention and indiscriminate friendliness, thus suggesting that parenting quality may moderate the effects of early institutional deprivation.

Relationships Among Childhood Maltreatment, Limbic System Dysfunction, and Eating Disorders in College Women.

The mechanisms linking childhood maltreatment and eating pathology are not fully understood. We examined the mediating role of limbic system dysfunction in the relationships between three forms of childhood maltreatment (parental psychological maltreatment, parental physical maltreatment, and parental emotional neglect) and eating disorder symptoms. A convenience sample of college women (N = 246, M age = 19.62, SD = 2.41) completed measures of maltreatment (Parent-Child Conflict Tactics Scales and the Parental Bonding Instrument), limbic system dysfunction (Limbic System Questionnaire), and eating pathology (Eating Disorder Examination Questionnaire). We hypothesized that there would be an indirect effect of each type of childhood maltreatment on eating disorder symptoms via limbic system irritability. Results generally supported the hypotheses. Examination of the individual paths that defined the indirect effect indicated that higher reported childhood maltreatment was associated with greater limbic irritability symptoms, and higher limbic irritability symptomatology was related to higher total eating disorder scores. There were no significant direct effects for any of the proposed models. Findings are in line with research supporting the role of limbic system dysfunction as a possible pathway in the maltreatment-eating disorder link. Given that limbic system dysfunction may underlie behavioral symptoms of eating disorders, efforts targeting limbic system dysfunction associated with child maltreatment might best be undertaken at an early developmental stage, although interventions for college women struggling with eating disorders are also crucial.