The Neurobiological Toll of Early Human Deprivation

Prenatal Social Determinants of Health: Narrative review of maternal environments and neonatal brain development

The Social Determinants of Health, a set of social factors including socioeconomic status, community context, and neighborhood safety among others, are well-known predictors of mental and physical health across the lifespan. Recent research has begun to establish the importance of these social factors at the earliest points of brain development, including during the prenatal period. Prenatal socioeconomic status, perceived stress, and neighborhood safety have all been reported to impact neonatal brain structure and function, with exploratory work suggesting subsequent effects on infant and child behavior. Secondary effects of the Social Determinants of Health, such as maternal sleep and psychopathology during pregnancy, have also been established as important predictors of infant brain development. This research not only establishes prenatal Social Determinants of Health as important predictors of future outcomes but may be effectively applied even before birth. Future research replicating and extending the effects in this nascent literature has great potential to produce more specific and mechanistic understanding of the social factors that shape early neurobehavioral development. IMPACT: This review synthesizes the research to date examining the effects of the Social Determinants of Health during the prenatal period and neonatal brain outcomes. Structural, functional, and diffusion-based imaging methodologies are included along with the limited literature assessing subsequent infant behavior. The degree to which results converge between studies is discussed, in combination with the methodological and sampling considerations that may contribute to divergence in study results. Several future directions are identified, including new theoretical approaches to assessing the impact of the Social Determinants of Health during the perinatal period.

The impact of out-of-home care on brain development: a brief review of the neuroscientific evidence informing our understanding of children's attachment outcomes

Researchers interested in the effects of early experiences of caregiving adversity have employed neuroscientific methods to illuminate whether and how such environmental input impacts on brain development, and whether and how such impacts underpin poor socioemotional outcomes in this population. Evidence is compelling in documenting negative effects on the individual's neurodevelopment following exposure to adverse or disadvantaged environments such as institutionalization or maltreatment. Neuroimaging research focused specifically on attachment-relevant processing of socioemotional stimuli and attachment outcomes among children looked-after is scarcer, but largely consistent. This review begins by summarizing the key general brain structural and functional alterations associated with caregiving deprivation. Then, neuroscientific evidence that is more directly relevant for understanding these children's attachment outcomes, both by employing social stimuli and by correlating children's neural markers with their attachment profiles, is reviewed. Brief interpretations of findings are suggested, and key limitations and gaps in the literature identified.

Importance of human milk for infants in the clinical setting: Updates and mechanistic links

INTRODUCTION

Human milk (HM) is the optimal source of nutrition for infants and has been implicated in multiple aspects of infant health. Although much of the existing literature has focused on the individual components that drive its nutrition content, examining HM as a biological system is needed for meaningful advancement of the field. Investigation of the nonnutritive bioactive components of HM and the maternal, infant, and environmental factors which affect these bioactives is important to better understand the importance of HM provision to infants. This information may inform care of clinical populations or infants who are critically ill, hospitalized, or who have chronic diseases and may benefit most from receiving HM.

METHODS

In this narrative review, we reviewed literature examining maternal and infant influences on HM composition with a focus on studies published in the last 10 years that were applicable to clinical populations.

RESULTS

We found multiple studies examining HM components implicated in infant immune and gut health and neurodevelopment. Additional work is needed to understand how donor milk and formula may be used in situations of inadequate maternal HM. Furthermore, a better understanding of how maternal factors such as maternal genetics and metabolic health influence milk composition is needed.

CONCLUSION

In this review, we affirm the importance of HM for all infants, especially clinical populations. An understanding of how HM composition is modulated by maternal and environmental factors is important to progress the field forward with respect to mechanistic links between HM biology and infant health outcomes.

Early Attachment and the Development of Social Communication: A Neuropsychological Approach

Social communication forms the foundation of human relationships. Social communication, i.e., the appropriate understanding and use of verbal and non-verbal communication within a social context, profoundly impacts mental health across the lifespan and is also highly vulnerable to neurodevelopmental threats and social adversities. There exists a strong interconnection between the development of language and other higher cognitive skills, mediated, in part, through the early attachment relationship. Consideration of how attachment links to brain development can help us understand individuals with social communication difficulties across the lifespan. The early attachment relationship supports the development of the foundational constructs of social communication. In this paper, a neuropsychological perspective was applied to social communication, which integrated evidence from early attachment theory, examining the underpinnings of social communication components identified by the SoCom model, namely socio-cognitive, socio-emotional, and socio-linguistic constructs. A neuropsychological perspective underscores the importance of interdisciplinary collaboration. This should also inform approaches to prevention, policy, intervention, and advocacy for individuals with or at risk for social communication impairments, as well as their families.

Painful Truth: The Need to Re-Center Chronic Pain on the Functional Role of Pain

Pain is undesirable, whether it is a symptom of mild or severe illness or instead indicates disorder in the nervous system’s ability to perceive and process sensory information. Nonetheless, pain is part of the body’s ability to defend itself and promote its own survival—this is its fundamental evolutionary function. This normal expression of pain is not limited to what is considered useful because it alerts us to the initiation of illness. It also applies to pain that continues when illness or noxious stimuli persist. However, the parameters of what is here termed functional pain are not fully understood and are seldom explicitly the focus of research. This paper posits that failure to appreciate the functional role of pain in research has had significant unintended consequences and may be contributing to inconsistent research findings. To that end, the paper describes the misclassification issue at the core of chronic pain research—whether a given pain reflects functional or pathological processes—and discusses research areas where reconsidering the functional role of pain may lead to advancements.

The neurobiology of childhood trauma, from early physical pain onwards: as relevant as ever in today's fractured world

Background: The situation in the world today, encompassing multiple armed conflicts, notably in Ukraine, the Coronavirus pandemic and the effects of climate change, increases the likelihood of childhood exposure to physical injury and pain. Other effects of these worldwide hardships include poverty, malnutrition and starvation, also bringing with them other forms of trauma, including emotional harm, neglect and deliberate maltreatment. Objective: To review the neurobiology of the systems in the developing brain that are most affected by physical and emotional trauma and neglect. Method: The review begins with those that mature first, such as the somatosensory system, progressing to structures that have a more protracted development, including those involved in cognition and emotional regulation. Explored next are developing stress response systems, especially the hypothalamic-pituitary-adrenal axis and its central regulator, corticotropin-releasing hormone. Also examined are reward and anti-reward systems and genetic versus environmental influences. The behavioural consequences of interpersonal childhood trauma, focusing on self-harm and suicide, are also surveyed briefly. Finally, pointers to effective treatment are proffered. Results: The low-threshold nature of circuitry in the developing brain and lack of inhibitory connections therein result in heightened excitability, making the consequences of both physical and emotional trauma more intense. Sensitive and critical periods in the development of structures such as the amygdala render the nervous system more vulnerable to insults occurring at those points, increasing the likelihood of psychiatric disorders, culminating in self-harm and even suicide. Conclusion: In view of the greater excitability of the developing nervous system, and its vulnerability to physical and psychological injuries, the review ends with an exhortation to consider the long-term consequences of childhood trauma, often underestimated or missed altogether when faced with adults suffering mental health problems.

Success at Scale: Outcomes of Community-Based Neurodevelopment Intervention (CASITA) for Children Ages 6-20 months With Risk of Delay in Lima, Peru

This study is a randomized controlled trial of a 12-week community-based group parenting intervention ("CASITA") in Lima, Peru. CASITA improved neurodevelopment in a pilot study of 60 Peruvian children and subsequently scaled to 3,000 households throughout the district. The objective of this study was to assess intervention effectiveness when implemented at scale. A total of 347 children ages 6-20 months (52.7% male, 100% identified as "mestizo") at risk for developmental difficulties were randomized to immediate or delayed CASITA. At 3 months after enrollment, the immediate arm showed significantly higher overall development, based on the Extended Ages and Stages Questionnaire and Home Observation for Measurement of the Environment scores (Cohen's ds = .36 and .31, respectively). Programs demonstrably effective at scale could help address children's development risks worldwide.

ADHD Symptomatology, Executive Function and Cognitive Performance Differences between Family Foster Care and Control Group in ADHD-Diagnosed Children

Children in foster care have a high prevalence of attention deficit and hyperactivity disorder (ADHD) diagnosis, together with other difficulties in inattentive/hyperactive behaviors, executive and cognitive processes. Early exposure to adversity is a risk factor for developing ADHD via neurodevelopmental pathways. The goal of this research is (a) to study the cognitive and executive performance and inattentive/hyperactive behavior of ADHD-diagnosed children living in foster families in Spain, and (b) to analyze the role of placement variables in their performance. The sample was composed of 102 ADHD-diagnosed children aged 6- to 12-years-old, divided into two groups: 59 children living with non-relative foster families and 43 children not involved with protection services. Children’s executive function–inhibition, working memory, flexibility, attention, intellectual capacity, verbal comprehension, perceptive reasoning, working memory and processing speed were assessed using objective testing measures. At the same time, parents and teachers reported on children’s inattentive, hyperactive and impulsive behaviors. Children in foster care obtained lower scores in the general ability index than the control group after controlling the age at assessment. However, no differences were found in executive processes. Regarding placement factors, children with shorter exposure to adversities in their birth families and more time in foster care showed better executive performance. Professionals should consider the placement history of children in foster care and its influence on their symptomatology and cognitive capacities.

Early Rearing Conditions Affect Monoamine Metabolite Levels During Baseline and Periods of Social Separation Stress: A Non-human Primate Model (Macaca mulatta)

A variety of studies show that parental absence early in life leads to deleterious effects on the developing CNS. This is thought to be largely because evolutionary-dependent stimuli are necessary for the appropriate postnatal development of the young brain, an effect sometimes termed the "experience-expectant brain," with parents providing the necessary input for normative synaptic connections to develop and appropriate neuronal survival to occur. Principal among CNS systems affected by parental input are the monoamine systems. In the present study, N = 434 rhesus monkeys (233 males, 201 females) were reared in one of two conditions: as mother-reared controls (MR; n = 269) or without adults with 24-h access to same-aged peers (PR; n = 165). When subjects were six-months-old, they underwent a separation paradigm involving 4, sequential, four-day social separations from their mothers or peers, with each separation followed by three-day reunions with their mothers or their peers. Prior to the separation paradigm, baseline cisternal CSF samples were obtained, as well as at the end of each the four social separations, and after final separation, during a recovery period. CSF was assayed for concentrations of monoamine metabolites and a blood sample was genotyped for the serotonin transporter (5-HTT) genotype. Replicating earlier landmark findings, PR subjects with the s allele exhibited lower baseline concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), when compared to PR subjects homozygous for the L allele. MR subjects were undifferentiated by genotype. PR subjects exhibited lower CSF 5-HIAA concentrations during baseline, but higher CSF 5-HIAA during social separations, when compared to MR subjects. There were rearing effects for the dopamine metabolite homovanillic acid (HVA) and for the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), with PR subjects showing higher HVA and lower MHPG when compared to MR subjects. These findings indicate that there are long-term deficits in the response of monoamines following early maternal absence. The results of this study confirm and extend earlier findings that early parental absence has deleterious consequences for the development of the monoamine systems, and that these consequences are modulated by the 5-HTT genotype.

Accelerated maturation in functional connectivity following early life stress: Circuit specific or broadly distributed?

Psychosocial acceleration theory and other frameworks adapted from life history predict a link between early life stress and accelerated maturation in several physiological systems. Those findings led researchers to suggest that the emotion-regulatory brain circuits of previously-institutionalized (PI) youth are more mature than youth raised in their biological families (non-adopted, or NA, youth) during emotion tasks. Whether this accelerated maturation is evident during resting-state fMRI has not yet been established. Resting-state fMRI data from 83 early adolescents (Mage = 12.9 years, SD = 0.57 years) including 41 PI and 42 NA youth, were used to examine seed-based functional connectivity between the amygdala and ventromedial prefrontal cortex (vmPFC). Additional whole-brain analyses assessed group differences in functional connectivity and associations with cognitive performance and behavior. We found group differences in amygdala - vmPFC connectivity that may be consistent with accelerated maturation following early life stress. Further, whole-brain connectivity analyses revealed group differences associated with internalizing and externalizing symptoms. However, the majority of whole-brain results were not consistent with an accelerated maturation framework. Our results suggest early life stress in the form of institutional care is associated with circuit-specific alterations to a frontolimbic emotion-regulatory system, while revealing limited differences in more broadly distributed networks.

Better Language - Faster Helper: The Relation Between Spontaneous Instrumental Helping Action and Language Ability in Family-Reared and Institutionalized Toddlers

Background

Prosocial behavior is the key component of social and interpersonal relations. One of the elements of prosociality is helping behavior, which emerges already in early childhood. Researchers have identified several domains of helping behavior: instrumental helping, comforting another person, and sharing resources with others. The development of helping behavior can depend on a number of factors: children's age, the social situation of development, communication skills, and the ability to understand the feelings and needs of another person.

Objective

In Study 1, the main goal was to determine the effects of age and cognitive, language, and motor development on instrumental helping skills in early childhood. The goal of Study 2 was to estimate the effects of rearing in an adverse social environment by comparing the capacity for instrumental helping in family-raised and institutionalized children.

Design

The authors examined toddlers' (N = 198) ability to initiate spontaneous helping and the factors that may influence it. Cognitive, language, and fine motor skills were measured by the Bayley Scales of Infant and Child Development, 3rd edition. Children's instrumental helping behavior was assessed according to the procedure presented by Warneken and Tomasello, with a few modifications.

Results

Study 1 demonstrated that children's ability to initiate helping was dependent on their age: the non-helpers were significantly younger than the helpers. Children's language skills also played a significant role in their helping behavior. The children with higher language skills helped the adult more often and more quickly. Study 2 demonstrated that institutional placement per se was not related to toddlers' ability to initiate helping. Language ability was associated with helping behavior both in institution- and family-reared toddlers.

Conclusion

Instrumental helping in early childhood is related to children's age, language skills, and rearing conditions.

Psychosocial deprivation and receptive language ability: a two-sample study

Background

The quality of early caregiving experiences is a known contributor to the quality of the language experiences young children receive. What is unknown is whether, and if so, how psychosocial deprivation early in life is associated with long-lasting receptive language outcomes.

Methods

Two prospective longitudinal studies examining early psychosocial deprivation/neglect in different contexts (i.e., deprivation due to institutional care or deprivation experienced by children residing within US families) and receptive language as assessed via the Peabody Picture Vocabulary Test (PPVT) were used to assess the magnitude of these associations. First, 129 participants from the Bucharest Early Intervention Project, a randomized controlled trial of foster care as an alternative to institutional care in Romania, completed a receptive language assessment at age 18 years. Second, from the USA, 3342 participants from the Fragile Families and Child Wellbeing Study were assessed from infancy until middle childhood.

Results

Children exposed to early institutional care, on average, had lower receptive language scores than their never institutionalized counterparts in late adolescence. While randomization to an early foster care intervention had no long-lasting association with PPVT scores, the duration of childhood exposure to institutional care was negatively associated with receptive language. Psychosocial deprivation in US families was also negatively associated with receptive language longitudinally, and this association remained statistically significant even after accounting for measures of socioeconomic status.

Conclusion

Experiences of psychosocial deprivation may have long-lasting consequences for receptive language ability, extending to age 18 years. Psychosocial deprivation is an important prospective predictor of poorer receptive language.

Trial registration

Bucharest Early Intervention Project ClinicalTrials.gov Identifier: NCT00747396

Type of early life adversity confers differential, sex-dependent effects on early maturational milestones in mice

Early life adversity (ELA) increases risk for negative health outcomes, with sex disparities in prevalence and form of ELA experienced and risk for neuropsychiatric pathology. ELA comes in many forms (e.g. parental neglect/loss, limited access to resources) but whether disparate forms of ELA have common effects on outcomes, and if males and females are equally affected, remains unknown. Epidemiological studies often fail to accurately account for differences in type, timing, and duration of adversity experienced. Rodent models allow precise control of many of these variables. However, differences in the form of ELA, species, strain, housing, and testing paradigms used may contribute to differences in outcomes leading to questions of whether differences are the result of the form of ELA or these other variables. Here, we directly compared two mouse models of ELA, maternal separation (MS) and limited bedding (LB) in males and females on development of the body, motor and visual milestones, stress physiology, and anxiety-like behavior. LB affected timing of early milestones, somatic growth, and stress physiology in both sexes, yet only females showed later anxiety-like behaviors. MS rearing affected males and females similarly in early milestone development, yet only males showed changes in stress physiology and anxiety-like outcomes. These studies provide a platform to directly compare MS and LB models within one lab. The current work advances our understanding of the unique features of ELA that shape early neurodevelopmental events and risk for later pathology, increasing the translational relevance of these ELA models.

CONTRIBUIÇÕES DOS ESTUDOS DE AUTORES SOVIÉTICOS PARA A PSICOLOGIA E A NEUROCIÊNCIA COGNITIVA CONTEMPORÂNEAS

RESUMO Os autores soviéticos introduziram o conceito de “mente” como sistema funcional complexo (SFC) de origem histórico-cultural, confirmado e avançado pela psicologia e pela neurociência cognitiva atual. Como SFC, o ato mental é um conjunto dinâmico de operações abstratas processadas em diversas regiões cerebrais interconexas, cada uma contribuindo com uma operação específica, como ocorre na memória e na solução de problemas. Os SFC constroem-se na atividade prática psicossocial do indivíduo, mediada por pessoas e signos, cuja privação, em períodos críticos do desenvolvimento mental-cerebral, pode ser catastrófica.

PREFÁCIO PARA O LIVRO DE A. N. LEONTIEV O DESENVOLVIMENTO DA MEMÓRIA

RESUMO O presente texto consiste na primeira tradução do segundo “Prefácio” do livroO Desenvolvimento da Memória para a língua portuguesa. Tal texto, escrito em 1932, esboça uma breve autocrítica dos autores com relação ao ideário de psicologia instrumental existente no livro prefaciado, o qual perpassou a pesquisa de Leontiev, orientada por Vigotski. Os autores revisam tópicos como a importância da idade na memorização e a sobrevivência de formas “inferiores” nas formas “superiores” de memória, traçando importantes contribuições acerca dos conceitos de “memória/memorização” e de “sentido”.

A Systematic Review of Reviews of the Outcome of Severe Neglect in Underresourced Childcare Institutions

The aim of the systematic review described in this article was to determine the outcomes for individuals exposed to severe neglect in congregate care institutions such as orphanages. In this context, severe neglect refers to failure to meet children's basic physical, developmental, and emotional needs due to inadequate resources. In this systematic review of previous systematic reviews and meta-analyses, searches of 10 databases were conducted, 18 papers that met inclusion and exclusion criteria were selected for review, their quality was assessed, and data were extracted and synthesized. The 550 primary studies included in the 18 systematic reviews and meta-analyses were relatively well designed, allowing confidence to be placed in their results. Severe neglect was associated with a wide range of problems in the domains of physical development, cognitive development, attachment, and mental health. The severity of adverse outcomes was partly influenced by the duration and severity of deprivation and a constellation of risk and protective factors. Prevention policies should aim to eliminate large underresourced congregate care institutions for infants. In taking steps toward this, policies should aim to adequately resource congregate care institutions to meet children's developmental needs for nutrition, stimulation, and attachment to a stable primary caregiver with adequate parenting skills and training. Early placement in adoptive or foster families, with access to routine physical and mental health-care service available in developed countries, is the most viable effective intervention for child survivors of severe neglect.

Early life stress and brain function: Activity and connectivity associated with processing emotion and reward

Investigating the developmental sequelae of early life stress has provided researchers the opportunity to examine adaptive responses to extreme environments. A large body of work has established mechanisms by which the stressful experiences of childhood poverty, maltreatment, and institutional care can impact the brain and the distributed stress systems of the body. These mechanisms are reviewed briefly to lay the foundation upon which the current neuroimaging literature has been built. More recently, developmental cognitive neuroscientists have identified a number of the effects of early adversity, including differential behavior and brain function. Among the most consistent of these findings are differences in the processing of emotion and reward-related information. The neural correlates of emotion processing, particularly frontolimbic functional connectivity, have been well studied in early life stress samples with results indicating accelerated maturation following early adversity. Reward processing has received less attention, but here the evidence suggests a deficit in reward sensitivity. It is as yet unknown whether the accelerated maturation of emotion-regulation circuits comes at the cost of delayed development in other systems, most notably the reward system. This review addresses the early life stress neuroimaging literature that has investigated emotion and reward processing, identifying important next steps in the study of brain function following adversity.

The role of early care and education in addressing early childhood trauma

Young children's experience of trauma is associated with a wide range of adverse events and circumstances, including abuse and neglect, domestic violence, loss of a parent, and community violence. Policymakers and practitioners are increasingly aware that trauma during the first few years of life is especially widespread, and there is growing interest in new ways to support these young children and their families. Many young children who experience trauma attend early care and education (ECE) programs, and these settings offer important opportunities to promote their well-being. This paper examines strategies currently being implemented in ECE to address early childhood trauma. The paper first examines research on how trauma affects young children's development, ECE environments, and society. We then describe the unique needs of young, traumatized children and features of trauma-informed care that can address their needs, along with emerging interventions and supports that can be incorporated into or linked with ECE settings as part of a trauma-informed approach. We conclude with a discussion of future directions for ECE and trauma research, policy, and practice, bearing in mind both the promise of new approaches and a limited evidence base to date.

Early-life adversity and neurological disease: age-old questions and novel answers

Neurological illnesses, including cognitive impairment, memory decline and dementia, affect over 50 million people worldwide, imposing a substantial burden on individuals and society. These disorders arise from a combination of genetic, environmental and experiential factors, with the latter two factors having the greatest impact during sensitive periods in development. In this Review, we focus on the contribution of adverse early-life experiences to aberrant brain maturation, which might underlie vulnerability to cognitive brain disorders. Specifically, we draw on recent robust discoveries from diverse disciplines, encompassing human studies and experimental models. These discoveries suggest that early-life adversity, especially in the perinatal period, influences the maturation of brain circuits involved in cognition. Importantly, new findings suggest that fragmented and unpredictable environmental and parental signals comprise a novel potent type of adversity, which contributes to subsequent vulnerabilities to cognitive illnesses via mechanisms involving disordered maturation of brain 'wiring'.

Association Between Prematurity and Diagnosis of Neurodevelopment Disorder: A Case-Control Study

The aim of this study is to investigate the association between prematurity and diagnosis of neurodevelopmental disorders (ND) (attention deficit/hyperactivity disorder [ADHD] or autism spectrum disorder [ASD]) in Brazilian children and adolescents. Case-control study based on medical records data from a specialized outpatient clinic. Prematurity was defined as gestational age less than 37 weeks. Prematurity was independently associated with diagnosis of a ND (adjusted odds ratio [AOR] 3.46, 95% CI 1.15 - 7.92), as well as with ADHD and ASD diagnosis after a multiple logistic regression analysis. These findings from Brazilian patients are related to what is found in the literature worldwide. Efforts to modify risk factors, such as prematurity, may impact incidence reduction of both ADHD and ASD.

Programming of Stress-Sensitive Neurons and Circuits by Early-Life Experiences

Early-life experiences influence brain structure and function long-term, contributing to resilience or vulnerability to stress and stress-related disorders. Therefore, understanding the mechanisms by which early-life experiences program specific brain cells and circuits to shape life-long cognitive and emotional functions is crucial. We identify the population of corticotropin-releasing hormone (CRH)-expressing neurons in the hypothalamic paraventricular nucleus (PVN) as a key, early target of early-life experiences. Adverse experiences increase excitatory neurotransmission onto PVN CRH cells, whereas optimal experiences, such as augmented and predictable maternal care, reduce the number and function of glutamatergic inputs onto this cell population. Altered synaptic neurotransmission is sufficient to initiate large-scale, enduring epigenetic re-programming within CRH-expressing neurons, associated with stress resilience and additional cognitive and emotional outcomes. Thus, the mechanisms by which early-life experiences influence the brain provide tractable targets for intervention.

Early Sexual Trauma Exposure and Neural Response Inhibition in Adolescence and Young Adults: Trajectories of Frontal Theta Oscillations During a Go/No-Go Task

OBJECTIVE

Trauma, particularly when experienced early in life, can alter neurophysiologic and behavioral development, thereby increasing risk for substance use disorders and related psychopathology. However, few studies have empirically examined trauma using well-characterized developmental samples that are followed longitudinally.

METHOD

The association of assaultive, non-assaultive, and sexual assaultive experiences before 10 years of age with developmental trajectories of brain function during response inhibition was examined by measuring electrophysiologic theta and delta oscillations during no-go and go conditions in an equal probability go/no-go task. Data were drawn from the Collaborative Study of the Genetics of Alcoholism (COGA) prospective cohort, composed of offspring who were aged 12 through 22 years at enrollment from high-risk and comparison families, with follow-ups at 2-year intervals since 2004. In addition, other important predictors of neurophysiologic functioning (eg, substance use, impulsivity, and parental alcohol use disorders) were investigated. Moreover, associations of neurophysiologic functioning with alcohol and cannabis use disorder symptom counts and externalizing and internalizing psychopathology were examined.

RESULTS

Individuals exposed to sexual assaultive trauma before 10 years of age had slower rates of change in developmental trajectories of no-go frontal theta during response inhibition. Importantly, effects remained significant after accounting for exposure to other traumatic exposures, such as parental history of alcohol use disorder and participants' substance use, but not measures of impulsivity. Further, slower rates of change in no-go frontal theta adolescent and young adult development were associated with increased risk for alcohol use disorder symptoms and internalizing psychopathology, but not for cannabis use disorder symptoms or externalizing psychopathology.

CONCLUSION

Childhood sexual assault is associated with atypical frontal neurophysiologic development during response inhibition. This could reflect alterations in frontal lobe development, synaptic pruning, and/or cortical maturation involving neural circuits for inhibitory control. These same areas could be associated with increased risk for young adult alcohol use disorder symptoms and internalizing psychopathology. These findings support the hypothesis that changes in neurocognitive development related to early sexual trauma exposure could increase the risk for mental health and substance use problems in young adulthood.

Autism Pathogenesis: The Superior Colliculus

After been exposed to the visual input, in the first year of life, the brain experiences subtle but massive changes apparently crucial for communicative/emotional and social human development. Its lack could be the explanation of the very high prevalence of autism in children with total congenital blindness. The present theory postulates that the superior colliculus is the key structure for such changes for several reasons: it dominates visual behavior during the first months of life; it is ready at birth for complex visual tasks; it has a significant influence on several hemispheric regions; it is the main brain hub that permanently integrates visual and non-visual, external and internal information (bottom-up and top-down respectively); and it owns the enigmatic ability to take non-conscious decisions about where to focus attention. It is also a sentinel that triggers the subcortical mechanisms which drive social motivation to follow faces from birth and to react automatically to emotional stimuli. Through indirect connections it also activates simultaneously several cortical structures necessary to develop social cognition and to accomplish the multiattentional task required for conscious social interaction in real life settings. Genetic or non-genetic prenatal or early postnatal factors could disrupt the SC functions resulting in autism. The timing of postnatal biological disruption matches the timing of clinical autism manifestations. Astonishing coincidences between etiologies, clinical manifestations, cognitive and pathogenic autism theories on one side and SC functions on the other are disclosed in this review. Although the visual system dependent of the SC is usually considered as accessory of the LGN canonical pathway, its imprinting gives the brain a qualitatively specific functions not supplied by any other brain structure.

Trajectories of psychopathology in extremely low birth weight survivors from early adolescence to adulthood: a 20-year longitudinal study

BACKGROUND

Individuals born extremely preterm are exposed to significant perinatal stresses that are associated with an increased risk of psychopathology. However, a paucity of longitudinal studies has prevented the empirical examination of long-term, dynamic effects of perinatal adversity on mental health. Here, internalizing and externalizing problems from adolescence through adulthood were compared in individuals born at extremely low birth weight (ELBW; <1,000 g) and normal birth weight (NBW; >2,500 g).

METHODS

Internalizing and externalizing data were collected over 20 years in three waves, during adolescence, young adulthood, and adulthood. Growth models were used to compare longitudinal trajectories in a geographically based sample of 151 ELBW survivors and 137 NBW control participants born between 1977 and 1982 matched for age, sex, and socioeconomic status at age 8.

RESULTS

After adjusting for sex, socioeconomic and immigrant status, and family functioning, ELBW survivors failed to show the normative, age-related decline in internalizing problems over time relative to their NBW peers (β = .21; p < .01). Both groups exhibited small declines in externalizing problems over the same period. Self-esteem (but not physical health, IQ, or maternal mood) partially mediated the association between ELBW status and internalizing problems.

CONCLUSIONS

Extremely low birth weight survivors experienced a blunting of the expected improvement in depression and anxiety from adolescence to adulthood. These findings suggest that altered physiological regulatory systems supporting emotional and cognitive processing may contribute to the maintenance of internalizing problems in this population.

Effect of Caregiver's Mental Health on Early Childhood Development across Different Rural Communities in China

Previous research has found that there are high rates of developmental delays among infants and toddlers in rural areas of China. Caregiver mental health problems might be one significant predictor of developmental delays among infants and toddlers, as has been found in other areas of the world. One way that the mental health of caregivers could affect early childhood development is through its effect on parenting practices. In this study, we used data from four major subpopulations of rural China to measure the correlation of caregiver mental health problems with the developmental outcomes of infants and toddlers. To do so, the study used the Bayley Scales of Infant Development III (BSID III) to examine the rates of developmental delays among 2514 rural infants/toddlers aged 6–30 months old. The results of the testing demonstrate that 48% of the sample’s infants/toddlers have cognitive delays; 52% have language delays; 53% have social-emotional delays; and 30% have motor delays. The data collection team also assessed caregiver mental health by using the Depression Anxiety Stress Scales (DASS-21) questionnaire. According to the findings, 39% of caregivers in the sample have symptoms of at least one kind of mental health problem (depression, anxiety, or stress). We also found that most caregivers do not engage in positive parenting practices, while a significant share of caregivers engage in negative parenting practices. The statistical analysis found that showing signs of mental health problems is significantly and negatively associated with infant/toddler developmental outcomes. The study also found that caregivers who show signs of mental health problems are significantly less likely to engage in interactive parenting practices. The study confirms that society needs to pay more attention to caregiver mental health problems in order to improve infant/toddler developmental outcomes in rural China and increase human capital accumulation in China as a whole.

Risk taking, decision-making, and brain volume in youth adopted internationally from institutional care

Early life stress in the form of early institutional care has been shown to have wide-ranging impacts on the biological and behavioral development of young children. Studies of brain structure using magnetic resonance imaging have reported decreased prefrontal volumes, and a large literature has detailed decreased executive function (EF) in post-institutionalized (PI) youth. Little is known about how these findings relate to decision-making, particularly in PI youth entering adolescence-a period often characterized by social transition and increased reliance upon EF skills and the still-maturing prefrontal regions that support them. As decision-making in risky situations can be an especially important milestone in early adolescence, a clearer knowledge of the relationship between risky decision making and prefrontal structures in post-institutionalized youth is needed. The youth version of the Balloon Analogue Risk Task and a two-deck variant of the Iowa Gambling Task were used to assess risky decision-making in post-institutionalized youth and a community control group (N = 74, PI = 44, Non-adopted = 30; mean age = 12.93). Participants also completed a structural MRI scan for the assessment of group differences in brain structure. We hypothesized that participants adopted from institutions would display poorer performance on risky-decision making tasks and smaller brain volumes compared to non-adopted youth. Results indicated that later-adopted participants made fewer risky decisions than those experiencing shorter periods of deprivation or no institutional rearing. Further, decreased prefrontal volumes were observed in later-adopted youth and were significantly associated with task performance. Our results suggest that changes in risky-decision making behavior and brain structure are associated with the duration of early institutional care.

The Boy Who Was Hit in the Face: Somatic Regulation and Processing of Preverbal Complex Trauma

Examination of novel treatment for complexly traumatized youth, in particular, those exposed to preverbal trauma, is necessary given challenges associated with effective intervention for this population. Therapies that facilitate somatic regulation have demonstrated benefit for some trauma survivors. The current article briefly reviews the emerging literature on symptoms of and treatments for complex and preverbal child trauma and describes Sensory Motor Arousal Regulation Therapy (SMART), an intervention for child and adolescent trauma with preliminary empirical support. SMART aims to enhance sensory motor engagement and promote affective, behavioral and physiological regulation using somatic regulation and sensory integration techniques. Utilizing case study methodology, the article illustrates application of SMART in treatment of a latency-aged child with history of exposure to complex and preverbal traumatic experiences. Case analysis suggests the potential contribution of enhanced somatic regulation in traumatized children toward increased relational engagement, behavioral and emotional regulation, and trauma processing.

Is Infant/Toddler Anemia a Problem across Rural China? A Mixed-Methods Analysis

In the past, iron-deficiency anemia in children has had a widespread presence in rural China. Given the recent economic growth in China, it is unclear if anemia among infants/toddlers remains a problem. The objective of this study is to measure the anemia rate in rural Chinese infants/toddlers across four major subpopulations and attempt to discover the sources of anemia. We use a mixed-methods approach combining quantitative data on 2909 rural Chinese infants/toddlers and their families with qualitative interviews with 84 caregivers of infants aged 6 to 30 months. Quantitative analysis indicates that the overall prevalence of anemia (43%) within sampled infants/toddlers was high, especially in comparison to the low rates of stunting (2⁻5%), being underweight (2%), and wasting (2⁻4%). These findings suggest that in rural China, anemia stems from the poor quality of the diets of infants/toddlers, rather than insufficient quantities of food being consumed. Qualitative analysis illustrates the factors that are contributing to anemia. Caregivers do not understand the causes of this condition, the symptoms that would lead one to recognize this condition, or the steps needed to treat their child with this condition. The findings offer a comprehensive understanding of the limited awareness of anemia among rural Chinese caregivers.

Maternal Regulation of Pups' Cortical Activity: Role of Serotonergic Signaling

A developing brain shows intense reorganization and heightened neuronal plasticity allowing for environmental modulation of its development. During early life, maternal care is a key factor of this environment and defects in this care can derail adaptive brain development and may result in susceptibility to neuropsychiatric disorders. Nevertheless, the mechanisms by which those maternal interactions immediately impact the offspring's brain activity to initiate the pathway to pathology are not well understood. We do know that multiple neurotransmitter systems are involved, including the serotonergic system, a key neuromodulator involved in brain development and emotional regulation. We tested the importance of the serotonergic system and pups' immediate neural response to maternal presence using wireless electrophysiological recordings, a novel approach allowing us to record neural activity during pups' interactions with their mother. We found that maternal contact modulates the P10-P12 rat pups' anterior cingulate cortex (ACC) activity by notably increasing local-field potential (LFP) power in low-frequency bands. We demonstrated, by blocking serotonergic receptors, that this increase is mediated through 5-HT2 receptors (5-HT2Rs). Finally, we showed in isolated pups that enhancing serotonergic transmission, using a selective-serotonin-reuptake-inhibitor, is sufficient to enhance LFP power in low-frequency bands in a pattern similar to that observed when the mother is in the nest. Our results highlight a significant contribution of the serotonergic system in mediating changes of cortical activity in pups related to maternal presence.

Early life stress determines the effects of glucocorticoids and stress on hippocampal function: Electrophysiological and behavioral evidence respectively

Exposure to early-life adversity may program brain function to prepare individuals for adaptation to matching environmental contexts. In this study we tested this hypothesis in more detail by examining the effects of early-life stress - induced by raising offspring with limited nesting and bedding material from postnatal days 2-9 - in various behavioral tasks and on synaptic function in adult mice. Early-life stress impaired adult performance in the hippocampal dependent low-arousing object-in-context recognition memory task. This effect was absent when animals were exposed to a single stressor before training. Early-life stress did not alter high-arousing context and auditory fear conditioning. Early-life stress-induced behavioral modifications were not associated with alterations in the dendritic architecture of hippocampal CA1 pyramidal neurons or principal neurons of the basolateral amygdala. However, early-life stress reduced the ratio of NMDA to AMPA receptor-mediated excitatory postsynaptic currents and glutamate release probability specifically in hippocampal CA1 neurons, but not in the basolateral amygdala. These ex vivo effects in the hippocampus were abolished by acute glucocorticoid treatment. Our findings support that early-life stress can hamper object-in-context learning via pre- and postsynaptic mechanisms that affect hippocampal function but these effects are counteracted by acute stress or elevated glucocorticoid levels.

Early Socioemotional Intervention Mediates Long-Term Effects of Atypical Rearing on Structural Covariation in Gray Matter in Adult Chimpanzees

Atypical rearing has deleterious effects on chimpanzee behavior during development, some of which can be ameliorated with a responsive care intervention (RCI). Here, we obtained in vivo magnetic resonance images of adult brains of 27 chimpanzees given institutional care, with and without RCI, and compared them with those of 16 chimpanzees mother-reared from birth. We found significant long-term rearing effects on structural covariation and gray matter volume, specifically in the basal forebrain (i.e., caudate, putamen, nucleus accumbens, rectus gyrus, and orbital prefrontal cortex), indicating that RCI prevented brain changes due to atypical rearing. A significant correlation between covariation in these brain areas and caregiver nurturing, experienced in the first month of life, suggests a possible developmental mechanism for the effect of early experience on brain networks. We identified an early intervention that prevents changes in the basal forebrain that otherwise emerge as a consequence of institutionalized rearing without species-typical socioemotional experiences.

The Microbiome-Gut-Behavior Axis: Crosstalk Between the Gut Microbiome and Oligodendrocytes Modulates Behavioral Responses

Environmental and dietary stimuli have always been implicated in brain development and behavioral responses. The gut, being the major portal of communication with the external environment, has recently been brought to the forefront of this interaction with the establishment of a gut-brain axis in health and disease. Moreover, recent breakthroughs in germ-free and antibiotic-treated mice have demonstrated the significant impact of the microbiome in modulating behavioral responses in mice and have established a more specific microbiome-gut-behavior axis. One of the mechanisms by which this axis affects social behavior is by regulating myelination at the prefrontal cortex, an important site for complex cognitive behavior planning and decision-making. The prefrontal cortex exhibits late myelination of its axonal projections that could extend into the third decade of life in humans, which make it susceptible to external influences, such as microbial metabolites. Changes in the gut microbiome were shown to alter the composition of the microbial metabolome affecting highly permeable bioactive compounds, such as p-cresol, which could impair oligodendrocyte differentiation. Dysregulated myelination in the prefrontal cortex is then able to affect behavioral responses in mice, shifting them towards social isolation. The reduced social interactions could then limit microbial exchange, which could otherwise pose a threat to the survival of the existing microbial community in the host and, thus, provide an evolutionary advantage to the specific microbial community. In this review, we will analyze the microbiome-gut-behavior axis, describe the interactions between the gut microbiome and oligodendrocytes and highlight their role in the modulation of social behavior.

Prematuridade, Funções Executivas e Qualidade dos Cuidados Parentais: Revisão Sistemática de Literatura

RESUMO Este artigo de revisão visa contextualizar o desenvolvimento das funções executivas (FE) em crianças prematuras, com especial atenção para o efeito dos cuidados parentais. As principais bases eletrônicas foram utilizadas para essa revisão: 31 estudos originais, duas meta-análises, uma meta-síntese e dois artigos de revisão foram identificados. Concluiu-se que as crianças prematuras têm maior risco de disfunção executiva global, sendo a qualidade dos cuidados parentais fundamentais para a modulação das FE, nomeadamente no que concerne às variáveis socioemocionais da interação, como a sensibilidadematerna. Salientam-se ainda as principais limitações dos estudos analisados e apontam-se recomendações para futura investigação sobre os efeitos dos cuidados parentais no desenvolvimento de FE em crianças prematuras.

Chronic early life stress induced by limited bedding and nesting (LBN) material in rodents: critical considerations of methodology, outcomes and translational potential

The immediate and long-term effects of exposure to early life stress (ELS) have been documented in humans and animal models. Even relatively brief periods of stress during the first 10 days of life in rodents can impact later behavioral regulation and the vulnerability to develop adult pathologies, in particular an impairment of cognitive functions and neurogenesis, but also modified social, emotional, and conditioned fear responses. The development of preclinical models of ELS exposure allows the examination of mechanisms and testing of therapeutic approaches that are not possible in humans. Here, we describe limited bedding and nesting (LBN) procedures, with models that produce altered maternal behavior ranging from fragmentation of care to maltreatment of infants. The purpose of this paper is to discuss important issues related to the implementation of this chronic ELS procedure and to describe some of the most prominent endpoints and consequences, focusing on areas of convergence between laboratories. Effects on the hypothalamic-pituitary adrenal (HPA) axis, gut axis and metabolism are presented in addition to changes in cognitive and emotional functions. Interestingly, recent data have suggested a strong sex difference in some of the reported consequences of the LBN paradigm, with females being more resilient in general than males. As both the chronic and intermittent variants of the LBN procedure have profound consequences on the offspring with minimal external intervention from the investigator, this model is advantageous ecologically and has a large translational potential. In addition to the direct effect of ELS on neurodevelopmental outcomes, exposure to adverse early environments can also have intergenerational impacts on mental health and function in subsequent generation offspring. Thus, advancing our understanding of the effect of ELS on brain and behavioral development is of critical concern for the health and wellbeing of both the current population, and for generations to come.

New insights into early-life stress and behavioral outcomes

Adverse early-life experiences, including various forms of early-life stress, have consistently been linked with vulnerability to cognitive and emotional disorders later in life. Understanding the mechanisms underlying the enduring consequences of early-life stress is an active area of research, because this knowledge is critical for developing potential interventions. Animal models of early-life stress typically rely on manipulating maternal/parental presence and care, because these are the major source of early-life experiences in humans. Diverse models have been created, and have resulted in a wealth of behavioral outcomes. Here we focus on recent findings highlighting early-life stress-induced behavioral disturbances, ranging from hippocampus-dependent memory deficits to problems with experiencing pleasure (anhedonia). The use of naturalistic animal models of chronic early-life stress provides insight into the spectrum of cognitive and emotional outcomes and enables probing the underlying mechanisms using molecular-, cellular-, and network-level approaches.

Diurnal cortisol after early institutional care-Age matters

Several studies have shown that young children who have experienced early caregiving adversity (e.g. previously institutionalization (PI)) exhibit flattened diurnal cortisol slopes; however, less is known about how these patterns might differ between children and adolescents, since the transition between childhood and adolescence is a time of purported plasticity in the hypothalamic-pituitary-adrenal (HPA) axis. PI youth experience a massive improvement in caregiving environment once adopted into families; therefore we anticipated that a developmental increase in HPA axis plasticity during adolescence might additionally allow for an enhanced enrichment effect by the adoptive family. In a cross-sectional sample of 197 youths (PI and Comparison; 4–15 years old) we observed age-related group differences in diurnal slope. First replicating previous findings, PI children exhibited flattened diurnal slope. This group difference, however, was not observed in adolescents. Moderation analyses showed that pubertal development, increased time with family, and early adoption contributed to the steeper diurnal cortisol slope in PI adolescents. These findings add support to existing theories positing that the transition between middle childhood and adolescence may mark an additional sensitive period for diurnal cortisol patterning, allowing PI youth to benefit from the enriched environment provided by adoptive parents during this period of development.

Reduced Working Memory Mediates the Link between Early Institutional Rearing and Symptoms of ADHD at 12 Years

Children who are raised in institutions show severe delays across multiple domains of development and high levels of psychopathology, including attention deficit/hyperactivity disorder (ADHD). Low performance in executive functions (EFs) are also common in institutionally reared children and often do not remediate following improvements in the caregiving environment. ADHD symptomatology also remains elevated even after children are removed from institutional care and placed in families. We investigate whether poor EF is a mechanism explaining elevated rates of ADHD in children reared in institutional settings in the Bucharest Early Intervention Project (BEIP). In the current study, we examine the potentially mediating role of poor EF in the association between institutionalization and symptoms of ADHD at age 12 years. A total of 107 children were assessed with the Cambridge Neuropsychological Test Automated Battery (CANTAB) on working memory, set-shifting and planning. We also obtained concurrent teacher reports on their levels of ADHD symptoms (inattention and impulsivity separately). Institutionalization strongly predicted elevations in symptoms of inattention and impulsivity at age 12 years (ps < 0.01). Indices of working memory and planning were also associated with ADHD after controlling for potential confounders (ps < 0.03). Mediation analyses revealed that poor working memory performance mediated the link between exposure to early institutionalization and higher scores of both inattention and impulsivity. These results replicate and extend the findings that we reported in the BEIP sample at age 8 years. Together, they suggest that compromised working memory is a key mechanism that continues to explain the strikingly high levels of ADHD in late childhood among children institutionalized in early life. Interventions targeting working memory may help to prevent ADHD among children exposed to institutional care.

Early severe institutional deprivation is associated with a persistent variant of adult attention-deficit/hyperactivity disorder: clinical presentation, developmental continuities and life circumstances in the English and Romanian Adoptees study

BACKGROUND

Early-life institutional deprivation is associated with attention-deficit/hyperactivity disorder (ADHD) later in childhood and adolescence. In this article, we examine, for the first time, the persistence of deprivation-related ADHD into young adulthood in a sample of individuals adopted as young children by UK families after periods in extremely depriving Romanian orphanages.

METHODS

We estimated rates of ADHD at age 15 years and in young adulthood (ages 22-25 years) in individuals at low (LoDep; nondeprived UK adoptees and Romanian adoptees with less than 6-month institutional exposure) and high deprivation-related risk (HiDep; Romanian adoptees with more than 6-month exposure). Estimates were based on parent report using DSM-5 childhood symptom and impairment criteria. At age 15, data were available for 108 LoDep and 86 HiDep cases, while in young adulthood, the numbers were 83 and 60, respectively. Data on education and employment status, IQ, co-occurring symptoms of young adult disinhibited social engagement (DSE), autism spectrum disorder (ASD), cognitive impairment, conduct disorder (CD), callous-unemotional (CU) traits, anxiety, depression and quality of life (QoL) were also collected.

RESULTS

ADHD rates in the LoDep group were similar to the general population in adolescence (5.6%) and adulthood (3.8%). HiDep individuals were, respectively, nearly four (19%) and over seven (29.3%) times more likely to meet criteria, than LoDep. Nine 'onset' young adult cases emerged, but these had a prior childhood history of elevated ADHD behaviours at ages 6, 11 and 15 years. Young adult ADHD was equally common in males and females, was predominantly inattentive in presentation and co-occurred with high levels of ASD, DSE and CU features. ADHD was associated with high unemployment and low educational attainment.

CONCLUSION

We provide the first evidence of a strong persistence into adulthood of a distinctively complex and impairing deprivation-related variant of ADHD. Our results confirm the powerful association of early experience with later development in a way that suggests a role for deep-seated alterations to brain structure and function.

Severe psychosocial deprivation in early childhood is associated with increased DNA methylation across a region spanning the transcription start site of CYP2E1

Exposure to adverse rearing environments including institutional deprivation and severe childhood abuse is associated with an increased risk for mental and physical health problems across the lifespan. Although the mechanisms mediating these effects are not known, recent work in rodent models suggests that epigenetic processes may be involved. We studied the impact of severe early-life adversity on epigenetic variation in a sample of adolescents adopted from the severely depriving orphanages of the Romanian communist era in the 1980s. We quantified buccal cell DNA methylation at ~400 000 sites across the genome in Romanian adoptees exposed to either extended (6-43 months; n=16) or limited duration (<6 months; n=17) of severe early-life deprivation, in addition to a matched sample of UK adoptees (n=16) not exposed to severe deprivation. Although no probe-wise differences remained significant after controlling for the number of probes tested, we identified an exposure-associated differentially methylated region (DMR) spanning nine sequential CpG sites in the promoter-regulatory region of the cytochrome P450 2E1 gene (CYP2E1) on chromosome 10 (corrected P=2.98 × 10(-5)). Elevated DNA methylation across this region was also associated with deprivation-related clinical markers of impaired social cognition. Our data suggest that environmental insults of sufficient biological impact during early development are associated with long-lasting epigenetic changes, potentially reflecting a biological mechanism linking the effects of early-life adversity to cognitive and neurobiological phenotypes.

The development of postinstitutionalized versus parent-reared Russian children as a function of age at placement and family type

A total of 149 children, who spent an average of 13.8 months in Russian institutions, were transferred to Russian families of relatives and nonrelatives at an average age of 24.7 months. After residing in these families for at least 1 year (average = 43.2 months), parents reported on their attachment, indiscriminately friendly behavior, social-emotional competencies, problem behaviors, and effortful control when they were 1.5-10.7 years of age. They were compared to a sample of 83 Russian parents of noninstitutionalized children, whom they had reared from birth. Generally, institutionalized children were rated similarly to parent-reared children on most measures, consistent with substantial catch-up growth typically displayed by children after transitioning to families. However, institutionalized children were rated more poorly than parent-reared children on certain competencies in early childhood and some attentional skills. There were relatively few systematic differences associated with age at family placement or whether the families were relatives or nonrelatives. Russian parent-reared children were rated as having more problem behaviors than the US standardization sample, which raises cautions about using standards cross-culturally.

Toward Understanding How Early-Life Stress Reprograms Cognitive and Emotional Brain Networks

Vulnerability to emotional disorders including depression derives from interactions between genes and environment, especially during sensitive developmental periods. Adverse early-life experiences provoke the release and modify the expression of several stress mediators and neurotransmitters within specific brain regions. The interaction of these mediators with developing neurons and neuronal networks may lead to long-lasting structural and functional alterations associated with cognitive and emotional consequences. Although a vast body of work has linked quantitative and qualitative aspects of stress to adolescent and adult outcomes, a number of questions are unclear. What distinguishes 'normal' from pathologic or toxic stress? How are the effects of stress transformed into structural and functional changes in individual neurons and neuronal networks? Which ones are affected? We review these questions in the context of established and emerging studies. We introduce a novel concept regarding the origin of toxic early-life stress, stating that it may derive from specific patterns of environmental signals, especially those derived from the mother or caretaker. Fragmented and unpredictable patterns of maternal care behaviors induce a profound chronic stress. The aberrant patterns and rhythms of early-life sensory input might also directly and adversely influence the maturation of cognitive and emotional brain circuits, in analogy to visual and auditory brain systems. Thus, unpredictable, stress-provoking early-life experiences may influence adolescent cognitive and emotional outcomes by disrupting the maturation of the underlying brain networks. Comprehensive approaches and multiple levels of analysis are required to probe the protean consequences of early-life adversity on the developing brain. These involve integrated human and animal-model studies, and approaches ranging from in vivo imaging to novel neuroanatomical, molecular, epigenomic, and computational methodologies. Because early-life adversity is a powerful determinant of subsequent vulnerabilities to emotional and cognitive pathologies, understanding the underlying processes will have profound implications for the world's current and future children.