Socioeconomic status and structural brain development

Longitudinal Neuroimaging in Pediatric Traumatic Brain Injury: Current State and Consideration of Factors That Influence Recovery

Traumatic brain injury (TBI) is a leading cause of death and disability for children and adolescents in the U.S. and other developed and developing countries. Injury to the immature brain varies greatly from that of the mature, adult brain due to numerous developmental, pre-injury, and injury-related factors that work together to influence the trajectory of recovery during the course of typical brain development. Substantial damage to brain structure often underlies subsequent functional limitations that persist for years following pediatric TBI. Advances in neuroimaging have established an important role in the acute management of pediatric TBI, and magnetic resonance imaging (MRI) techniques have a particular relevance for the sequential assessment of long-term consequences from injuries sustained to the developing brain. The present paper will discuss the various factors that influence recovery and review the findings from the present neuroimaging literature to assess altered development and long-term outcome following pediatric TBI. Four MR-based neuroimaging modalities have been used to examine recovery from pediatric TBI longitudinally: (1) T1-weighted structural MRI is sensitive to morphological changes in gray matter volume and cortical thickness, (2) diffusion-weighted MRI is sensitive to changes in the microstructural integrity of white matter, (3) MR spectroscopy provides a sensitive assessment of metabolic and neurochemical alterations in the brain, and (4) functional MRI provides insight into the functional changes that occur as a result of structural damage and typical developmental processes. As reviewed in this paper, 13 cohorts have contributed to only 20 studies published to date using neuroimaging to examine longitudinal changes after TBI in pediatric patients. The results of these studies demonstrate considerable heterogeneity in post-injury outcome; however, the existing literature consistently shows that alterations in brain structure, function, and metabolism can persist for an extended period of time post-injury. With larger sample sizes and multi-site cooperation, future studies will be able to further examine potential moderators of outcome, such as the developmental, pre-injury, and injury-related factors discussed in the present review.

Socioeconomic and experiential influences on the neurobiology of language development

PURPOSE

The process by which young children acquire language is an incredible feat subserved by neurobiological language circuitry. While the foundations of brain structure and function are genetically determined, children's experiences during sensitive periods in early life have a significant influence on the development of language systems. The purpose of this review is to provide practitioners with a comprehensive summary of foundational and recent research on the ways that children's early experiences-both favorable and adverse-may influence the neuroanatomy and neurophysiology underlying language development. A specific focus is given to the burgeoning neuroimaging evidence of relationships between socioeconomic status (SES) and brain development, as well as to emerging research on proximal experiences that may serve as the direct mechanisms by which SES influences language development.

CONCLUSION

Findings from the neuroscience field have direct implications for practice in speech language pathology. Specifically, clinicians can have immense influence on crafting supportive language environments during windows of maximal neural influence, both via direct intervention and parent coaching. Practical suggestions are provided for translating research findings to practice.

The Dutch version of the Oxford Cognitive Screen (OCS-NL): normative data and their association with age and socio-economic status

The Oxford Cognitive Screen (OCS) is a screening tool designed for stroke patients, assessing attention, executive functions, language, praxis, numeric cognition and memory. Here we present norms for the two parallel versions of the Dutch OCS (OCS-NL, acquired in 246 participants for version A and a subset of 179 participants for version B. We evaluated the association of age and socio-economic status (i.e. education, income, occupation) with OCS-NL performance There were no systematic performance differences between income groups, nor between manual and non-manual workers. There were small differences between education groups. The association of education and performance did not vary across subtests. The association of age and performance varied across subtests, with the strongest associations for the naming, praxis, verbal memory and executive task. Thus, OCS-NL norms do not need to be stratified on income and occupation and age-specific norms are recommended for some subtests.

Socioeconomic Status and Reading Disability: Neuroanatomy and Plasticity in Response to Intervention

Although reading disability (RD) and socioeconomic status (SES) are independently associated with variation in reading ability and brain structure/function, the joint influence of SES and RD on neuroanatomy and/or response to intervention is unknown. In total, 65 children with RD (ages 6-9) with diverse SES were assigned to an intensive, 6-week summer reading intervention (n = 40) or to a waiting-list control group (n = 25). Before and after, all children completed standardized reading assessments and magnetic resonance imaging to measure cortical thickness. At baseline, higher SES correlated with greater vocabulary and greater cortical thickness in bilateral perisylvian and supramarginal regions-especially in left pars opercularis. Within the intervention group, lower SES was associated with both greater reading improvement and greater cortical thickening across broad, bilateral occipitotemporal and temporoparietal regions following the intervention. Additionally, treatment responders (n = 20), compared with treatment nonresponders (n = 19), exhibited significantly greater cortical thickening within similar regions. The waiting control and nonresponder groups exhibited developmentally typical, nonsignificant cortical thinning during this time period. These findings indicate that effective summer reading intervention is coupled with cortical growth, and is especially beneficial for children with RD who come from lower-SES home environments.

Conditions of Poverty, Parent-Child Interactions, and Toddlers' Early Language Skills in Low-Income Families

Objectives The study examined the relations between parent-child interaction in the first year of life to toddlers' language skills at age 2 years for a sample of children reared in poverty; of specific interest was testing the Family Stress Model, which proposes that the conditions of poverty influence children's language skills through caregiver well-being (e.g., distress, depression) and interaction dysregulation. Methods Participants were from the Kids in Columbus Study, a birth-cohort study of children born to urban families experiencing material hardship. Caregiver questionnaires were collected when the child was 4-7 months to document poverty conditions (maternal hardship, institutional resources), caregiver well-being (depression, distress), and dysregulation in parent-child interactions. The Bayley-III assessed receptive and expressive language skills when the children were 2 years. Results On average, receptive language skills were nearly 1 SD below the normative mean. Path models showed a significant effect of caregiver-child dysregulated interactions on toddlers' language skills, and an indirect effect of maternal distress on parent-child interactions and, in turn, toddlers' language skills. Conclusions for Practice This study confirmed the theoretical Family Stress Model as a viable representation of the effects of poverty on the language skills of toddlers reared in homes experiencing socioeconomic disadvantage.

The relationship between biological and psychosocial risk factors and resting-state functional connectivity in 2-month-old Bangladeshi infants: A feasibility and pilot study

Childhood poverty has been associated with structural and functional alterations in the developing brain. However, poverty does not alter brain development directly, but acts through associated biological or psychosocial risk factors (e.g. malnutrition, family conflict). Yet few studies have investigated risk factors in the context of infant neurodevelopment, and none have done so in low-resource settings such as Bangladesh, where children are exposed to multiple, severe biological and psychosocial hazards. In this feasibility and pilot study, usable resting-state fMRI data were acquired in infants from extremely poor (n = 16) and (relatively) more affluent (n = 16) families in Dhaka, Bangladesh. Whole-brain intrinsic functional connectivity (iFC) was estimated using bilateral seeds in the amygdala, where iFC has shown susceptibility to early life stress, and in sensory areas, which have exhibited less susceptibility to early life hazards. Biological and psychosocial risk factors were examined for associations with iFC. Three resting-state networks were identified in within-group brain maps: medial temporal/striatal, visual, and auditory networks. Infants from extremely poor families compared with those from more affluent families exhibited greater (i.e. less negative) iFC in precuneus for amygdala seeds; however, no group differences in iFC were observed for sensory area seeds. Height-for-age, a proxy for malnutrition/infection, was not associated with amygdala/precuneus iFC, whereas prenatal family conflict was positively correlated. Findings suggest that it is feasible to conduct infant fMRI studies in low-resource settings. Challenges and practical steps for successful implementations are discussed.

Vocabulary as a Central Link between Phonological Working Memory and Narrative Competence: Evidence from Monolingual and Bilingual Four-Year-Olds from Different Socioeconomic Backgrounds

Phonological working memory capacity, vocabulary size, and narrative competence are important skills in children's L1 and L2 acquisition, which may vary as a function of their language background and socioeconomic status (SES). We investigated test data of 56 typically developing 4-year-old kindergarten children from two SES and two language backgrounds: 29 children (15 higher SES, 14 lower SES) were monolingual German-speaking, and 27 children (14 higher SES, 13 lower SES) were successive Turkish-German bilinguals. The tests comprised a non-word repetition task testing phonological working memory, receptive vocabulary tests (in L1 and L2), and a narrative task. We investigated the effects of SES and language background on children's test performance. Results indicate that SES was a highly significant factor for phonological working memory and vocabulary in the monolingual children, but not in the bilingual children. Although the items of the non-word repetition task followed German phonotactic structure, lower SES (LSES) L2 children did not differ significantly from their monolingual LSES peers, demonstrating that there was no bilingual working memory disadvantage in the LSES group. A significant effect of language background was found for German vocabulary and for all categories of narrative competence, but only two slight SES effects on narrative competence. Significant correlations were found between phonological working memory and vocabulary as well as between vocabulary and narrative competence, but not between phonological working memory and narrative competence. Results suggest that phonological working memory and narrative competence are different domains of language awareness, and that vocabulary may act as the central variable mediating between them.

Diffusion kurtosis imaging of gray matter in schizophrenia

Prior postmortem studies have shown gray matter (GM) microstructural abnormalities in schizophrenia. However, few studies to date have examined GM microstructural integrity in schizophrenia in vivo. Here, we employed diffusion kurtosis imaging (DKI) to test for differences in GM microstructure in eighteen schizophrenia (SZ) patients versus nineteen healthy controls (HC). GM microstructure was characterized in each participant using DKI-derived metrics of mean kurtosis (MK) and mean diffusivity (MD). Individual T1-weighted images were used to create subject-specific cortically-labelled regions of interest (ROIs) of the four cortical lobes and sixty-eight cortical GM regions delineated by the Desikan-Killiany atlas, and to derive the associated cortical thickness and area measures. The derived ROIs were also registered to the diffusion space of each subject and used to generate region-specific mean MK and MD values. We additionally administered the Wisconsin Card Sorting Test (WCST), Stroop test, and Trail Making Test part B (Trails-B) to test the relationship between GM metrics and executive function in SZ. We found significantly increased MK and MD in SZ compared to HC participants in the temporal lobe, sub-lobar temporal cortical regions (fusiform, inferior temporal, middle temporal and temporal pole), and posterior cingulate cortex after correcting for multiple comparisons. Correlational analyses revealed significant associations of MK and MD with executive function scores derived from the WCST, Stroop, and Trails-B tests, along with an inverse relationship between MK and MD and cortical thickness and area. A hierarchical multiple linear regression analysis showed that up to 85% of the inter-subject variability in cognitive function in schizophrenia measured by the WCST could be explained by MK in combination with either GM thickness or area. MK and MD appear to be sensitive to GM microstructural pathology in schizophrenia and may provide useful biomarkers of abnormal cortical microstructure in this disorder.

Early childhood development: an imperative for action and measurement at scale

Experiences during early childhood shape biological and psychological structures and functions in ways that affect health, well-being and productivity throughout the life course. The science of early childhood and its long-term consequences have generated political momentum to improve early childhood development and elevated action to country, regional and global levels. These advances have made it urgent that a framework, measurement tools and indicators to monitor progress globally and in countries are developed and sustained. We review progress in three areas of measurement contributing to these goals: the development of an index to allow country comparisons of young children’s development that can easily be incorporated into ongoing national surveys; improvements in population-level assessments of young children at risk of poor early development; and the production of country profiles of determinants, drivers and coverage for early childhood development and services using currently available data in 91 countries. While advances in these three areas are encouraging, more investment is needed to standardise measurement tools, regularly collect country data at the population level, and improve country capacity to collect, interpret and use data relevant to monitoring progress in early childhood development.

Family history of Alzheimer's disease alters cognition and is modified by medical and genetic factors

In humans, a first-degree family history of dementia (FH) is a well-documented risk factor for Alzheimer’s disease (AD); however, the influence of FH on cognition across the lifespan is poorly understood. To address this issue, we developed an internet-based paired-associates learning (PAL) task and tested 59,571 participants between the ages of 18–85. FH was associated with lower PAL performance in both sexes under 65 years old. Modifiers of this effect of FH on PAL performance included age, sex, education, and diabetes. The Apolipoprotein E ε4 allele was also associated with lower PAL scores in FH positive individuals. Here we show, FH is associated with reduced PAL performance four decades before the typical onset of AD; additionally, several heritable and non-heritable modifiers of this effect were identified.

Disparities in Diffuse Cortical White Matter Integrity Between Socioeconomic Groups

There is a growing literature demonstrating a link between lower socioeconomic status (SES) and poorer neuroanatomical health, such as smaller total and regional gray and white matter volumes, as well as greater white matter lesion volumes. Little is known, however, about the relation between SES and white matter integrity. Here we examined the relation between SES and white matter integrity of the brain’s primary cortical regions, and evaluated potential moderating influences of age and self-identified race. Participants were 192 neurologically intact, community-dwelling African American and White adults (mean age = 52 years; 44% male, 60% White, low SES = 52%) from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Participants underwent 3.0-T cranial magnetic resonance imaging. Diffusion tensor imaging was used to estimate regional fractional anisotropy (FA) to quantify the brain’s white matter integrity and trace to capture diffusivity. Multiple regression analyses examined independent and interactive associations of SES, age, and race with FA of the frontal, temporal, parietal, and occipital lobes bilaterally. Sensitivity analyses assessed the influence of several biopsychosocial risk factors on these associations. Exploratory analyses examined these relations with trace and using additional SES indicators. Results indicated there were no significant interactions of SES, age, and race for any region. Individuals with low SES had lower FA in all regions, and higher trace in the right and left frontal, right and left temporal, and left occipital lobes. Findings remained largely unchanged after inclusion of sensitivity variables. Older age was associated with lower FA and greater trace for all regions, except for the right temporal lobe with FA. No main effects were found for race in FA, and Whites had higher trace values in the parietal lobes. Novel findings of this study indicate that relative to the high SES group, low SES was associated with poorer white matter integrity and greater diffusivity. These results may, in part, reflect exposures to various biopsychosocial risk factors experienced by those of lower SES across the lifespan, and may help explain the preponderance of cognitive and functional disparities between socioeconomic groups.

Brain structure mediates the association between socioeconomic status and attention-deficit/hyperactivity disorder

Low socioeconomic status (SES) is associated with greater risk for symptoms of attention-deficit/hyperactivity disorder (ADHD). One mechanism through which SES may confer risk for ADHD is by influencing brain structure. Alterations to cortical thickness, surface area and subcortical volume have been associated with low SES and with the presence of ADHD across multiple studies. The current study examined whether cortical thickness, surface area or subcortical volume mediate the associations between SES and ADHD in youth 3-21 years old (N = 874) from the Pediatric Imaging, Neurocognition and Genetics Study. Freesurfer was used to estimate cortical thickness, surface area and subcortical volume from structural magnetic resonance imaging. Parents reported on demographics, family SES, ADHD diagnoses and the presence of child attention problems. Statistical mediation was assessed using a bootstrap resampling procedure. Controlling for parental ADHD, child age, gender, birth weight and scanner, children in low SES families were more likely to be in the ADHD group. Consistent with previous reports in this sample, low SES was associated with reduced surface area across the frontal lobe and reduced subcortical volume in the amygdala, cerebellum, hippocampus and basal ganglia. Of these regions, a significant indirect effect of SES on ADHD status through subcortical volume was observed for the left cerebellum (95% confidence interval: 0.004, 0.022), the right cerebellum (95% confidence interval: 0.006, 0.025), and the right caudate (95% confidence interval: 0.002, 0.022). Environmentally mediated changes in the cerebellum and the caudate may be neurodevelopmental mechanisms explaining elevated risk of ADHD in children in low SES families.

Neonatal amygdalae and hippocampi are influenced by genotype and prenatal environment, and reflected in the neonatal DNA methylome

The amygdala and hippocampus undergo rapid development in early life. The relative contribution of genetic and environmental factors to the establishment of their developmental trajectories has yet to be examined. We performed imaging on neonates and examined how the observed variation in volume and microstructure of the amygdala and hippocampus varied by genotype, and compared with prenatal maternal mental health and socioeconomic status. Gene × Environment models outcompeted models containing genotype or environment only to best explain the majority of measures but some, especially of the amygdaloid microstructure, were best explained by genotype only. Models including DNA methylation measured in the neonate umbilical cords outcompeted the Gene and Gene × Environment models for the majority of amygdaloid measures and minority of hippocampal measures. This study identified brain region-specific gene networks associated with individual differences in fetal brain development. In particular, genetic and epigenetic variation within CUX1 was highlighted.

Association of Socioeconomic Status and Brain Injury With Neurodevelopmental Outcomes of Very Preterm Children

IMPORTANCE

Studies of socioeconomic status and neurodevelopmental outcome in very preterm neonates have not sensitively accounted for brain injury.

OBJECTIVE

To determine the association of brain injury and maternal education with motor and cognitive outcomes at age 4.5 years in very preterm neonates.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study of preterm neonates (24-32 weeks' gestation) recruited August 16, 2006, to September 9, 2013, at British Columbia Women's Hospital in Vancouver, Canada. Analysis of 4.5-year outcome was performed in 2018.

MAIN OUTCOMES AND MEASURES

At age 4.5 years, full-scale IQ assessed using the Wechsler Primary and Preschool Scale of Intelligence, Fourth Edition, and motor outcome by the percentile score on the Movement Assessment Battery for Children, Second Edition.

RESULTS

Of 226 survivors, neurodevelopmental outcome was assessed in 170 (80 [47.1%] female). Based on the best model to assess full-scale IQ accounting for gestational age, standardized β coefficients demonstrated the effect size of maternal education (standardized β = 0.21) was similar to that of white matter injury volume (standardized β = 0.23) and intraventricular hemorrhage (standardized β = 0.23). The observed and predicted cognitive scores in preterm children born to mothers with postgraduate education did not differ in those with and without brain injury. The best-performing model to assess for motor outcome accounting for gestational age included being small for gestational age, severe intraventricular hemorrhage, white matter injury volume, and chronic lung disease.

CONCLUSIONS AND RELEVANCE

At preschool age, cognitive outcome was comparably associated with maternal education and neonatal brain injury. The association of brain injury with poorer cognition was attenuated in children born to mothers of higher education level, suggesting opportunities to promote optimal outcomes.

Intellectual, adaptive and behavioural characteristics in four patients with 18p deletion syndrome

BACKGROUND

The association of behavioural phenotype assessment with cytogenomic characterisation may provide a better comprehension of genotype-phenotype correlations in syndromes caused by chromosomal abnormalities, such as 18p deletion syndrome.

METHOD

We report on four Brazilian patients with 18p deletion syndrome characterised by cytogenomic techniques and detailed neuropsychological evaluation. Intellectual, adaptive and behavioural characteristics were assessed through the Wechsler's Scales, the Vineland-II Scale and the Child Behaviour Checklist, respectively. Socio-economic measures including main caretaker educational level and family income as defined by Brazilian criteria for social class classification were also collected to evaluate a possible contribution of environmental factors in neurocognitive variability.

RESULTS

Two out of four patients showed intellectual disability (IQ < 70). Wechsler's scale results suggest that in our sample, interpretation of social situations based on observation of non-verbal behaviour constitute a cognitive strength while judgement of social rules and language skills associated with word knowledge and verbal fluency may be a cognitive weakness. Concerning adaptive behaviour, motor and socialisation domains showed to better develop than communication and daily living skills on the Vineland-II Scale. Only one patient presented internalising behavioural problems based on the Child Behaviour Checklist. Our results also suggested that socio-economic status may contribute to overall patient development.

CONCLUSION

Our results suggest that some 18p deletion syndrome patients may present average intellectual performance and that the segment deletion size and some families' socio-economic conditions may influence cognitive development.

Amygdala-prefrontal cortex white matter tracts are widespread, variable and implicated in amygdala modulation in adolescents

The amygdala is critically involved in processing emotion. Through bidirectional connections, the prefrontal cortex (PFC) is hypothesized to influence amygdala reactivity. However, research that elucidates the nature of amygdala-PFC interactions - through mapping amygdala-prefrontal tracts, quantifying variability among tracts, and linking this variability to amygdala activation - is lacking. Using probabilistic tractography to map amygdala-prefrontal white matter connectivity in 142 adolescents, the present study found that white matter connectivity was greater between the amygdala and the subgenual cingulate, orbitofrontal (OFC), and dorsomedial (dmPFC) prefrontal regions than with the dorsal cingulate and dorsolateral regions. Then, using a machine-learning regression, we found that greater amygdala-PFC white matter connectivity was related to attenuated amygdala reactivity. This effect was driven by amygdala white matter connectivity with the dmPFC and OFC, supporting implicit emotion processing theories which highlight the critical role of these regions in amygdala regulation. This study is among the first to map and compare specific amygdala-prefrontal white matter tracts and to relate variability in connectivity to amygdala activation, particularly among a large sample of adolescents from a well-sampled study. By examining the association between specific amygdala-PFC tracts and amygdala activation, the present study provides novel insight into the nature of this emotion-based circuit.

Metabolic and microstructural alterations in the SLE brain correlate with cognitive impairment

To address challenges in the diagnosis of cognitive dysfunction (CD) related to systemic lupus erythematosus-associated (SLE-associated) autoimmune mechanisms rather than confounding factors, we employed an integrated approach, using resting-state functional (FDG-PET) and structural (diffusion tensor imaging [DTI]) neuroimaging techniques and cognitive testing, in adult SLE patients with quiescent disease and no history of neuropsychiatric illness. We identified resting hypermetabolism in the sensorimotor cortex, occipital lobe, and temporal lobe of SLE subjects, in addition to validation of previously published resting hypermetabolism in the hippocampus, orbitofrontal cortex, and putamen/GP/thalamus. Regional hypermetabolism demonstrated abnormal interregional metabolic correlations, associated with impaired cognitive performance, and was stable over 15 months. DTI analyses demonstrated 4 clusters of decreased microstructural integrity in white matter tracts adjacent to hypermetabolic regions and significantly diminished connecting tracts in SLE subjects. Decreased microstructural integrity in the parahippocampal gyrus correlated with impaired spatial memory and increased serum titers of DNRAb, a neurotoxic autoantibody associated with neuropsychiatric lupus. These findings of regional hypermetabolism, associated with decreased microstructural integrity and poor cognitive performance and not associated with disease duration, disease activity, medications, or comorbid disease, suggest that this is a reproducible, stable marker for SLE-associated CD that may be may be used for early disease detection and to discriminate between groups, evaluate response to treatment strategies, or assess disease progression.

Determinants of Spatial Heterogeneity of Functional Illiteracy among School-Aged Children in the Philippines: An Ecological Study

Functional literacy is one of the targets of the Sustainable Development Goals (SDGs) of the United Nations. Functional literacy indicators are likely to vary between locations given the geographical variability of its major determinants. This property poses a challenge to decisions around efficient allocation of population services and resources to mitigate the impact of functional literacy in populations most in need. Using functional literacy indicators of 11,313 school-aged children collected in 2008 during the nationwide survey, the current study examined the association between functional literacy and geographical disparities in socioeconomic status (SES), water supply, sanitation and hygiene, household education stimuli, and environmental variables in all three regions of the Philippines (Luzon, the Visayas, and Mindanao). Three nested fixed-effects multinomial regression models were built to determine associations between functional literacy and a wide array of variables. Our results showed the general prevalence rate of functional illiteracy as being 4.7%, with the highest prevalence rate in the Visayas, followed by Mindanao and Luzon (7.5%, 6.9%, and 3.0%, respectively. Our results indicated that in Luzon prevalence of functional illiteracy was explained by variation in household education stimuli scores, sources of drinking water, and type of toilet facility. In Mindanao and the Visayas prevalence of functional illiteracy was primarily explained by geographical variation in SES, and natural environmental conditions. Our study highlights region-specific determinants of functional literacy and the need for geographically targeted, integrated interventions.

Neurocognitive Precursors of Substance Misuse Corresponding to Risk, Resistance, and Resilience Pathways: Implications for Prevention Science

Studies of substance misuse prevention generally focus on characteristics that typify risk, with the assumption that the prevalence of the problem will be optimally reduced by identifying, targeting, and reducing or eliminating risk factors. However, this risk-centered approach neglects variations in individual-level and environmental characteristics that portend differential pathways that are distinguishable by timing of substance use initiation (e.g., early versus delayed), the likelihood of use escalation versus eventual desistance, and enduring abstinence, despite exposure to significant risk factors. Considering the various underpinnings of these distinct substance use trajectories is critical to a more nuanced understanding of the effects, potency, and malleability of factors that are known to increase risk or confer protection. Here, we discuss three pathways relative to substance use patterns and predictors in the context of adversity, a well-known, highly significant influence on propensity for substance misuse. The first pathway is designated as "high risk" based on early onset of substance use, rapid escalation, and proneness to substance use disorders. Individuals who defy all odds and eventually exhibit adaptive developmental outcomes despite an initial maladaptive reaction to adversity, are referred to as "resilient." However, another categorization that has not been adequately characterized is "resistant." Resistant individuals include those who do not exhibit problematic substance use behaviors (e.g., early onset and escalation) and do not develop substance use disorders or other forms of psychopathology, despite significant exposure to factors that normally increase the propensity for such outcomes (e.g. trauma and/or adversity). In this paper, we apply this conceptualization of risk, resistance, and resilience for substance misuse to a more fine-grained analysis of substance use pathways and their corresponding patterns (e.g., non-use, initiation, escalation, desistance). The significance of the progression of neurocognitive functioning over the course of development is discussed as well as how this knowledge may be translated to make a science-based determination of intervention targets. This more encompassing theoretical model has direct implications for primary prevention and clinical approaches to disrupt risk pathways and to optimize long-term outcomes.

School climate is associated with cortical thickness and executive function in children and adolescents

A positive school climate has been found to support mental and physical health, academic achievement and social adjustment among youth. However, links between school climate and brain structure have not been investigated to date. In this study, we investigated whether school climate was associated with executive function (EF) and brain structure (cortical thickness and surface area) in children and adolescents. We further examined whether these links varied as a function of socioeconomic background. Participants who ranged from 9 to 18 years of age (N = 108) completed EF tasks and a high-resolution, 3-Tesla, T1-weighted magnetic resonance imaging (MRI) scan. Overall school climate, academic support, and family socioeconomic background were assessed using questionnaires. Higher academic support was associated with greater EF task performance and increased global cortical thickness. Additionally, academic support moderated the association between family income and EF, such that children from lower income families performed similarly to their more advantaged peers on EF tasks in the context of positive academic support. This work is the first to link school climate to brain structure and contributes to the growing body of evidence suggesting that academic support may be an important protective factor in the context of socioeconomic disadvantage.

Longitudinally Mapping Childhood Socioeconomic Status Associations with Cortical and Subcortical Morphology

Childhood socioeconomic status (SES) impacts cognitive development and mental health, but its association with human structural brain development is not yet well characterized. Here, we analyzed 1243 longitudinally acquired structural MRI scans from 623 youth (299 female/324 male) to investigate the relation between SES and cortical and subcortical morphology between ages 5 and 25 years. We found positive associations between SES and total volumes of the brain, cortical sheet, and four separate subcortical structures. These associations were stable between ages 5 and 25. Surface-based shape analysis revealed that higher SES is associated with areal expansion of lateral prefrontal, anterior cingulate, lateral temporal, and superior parietal cortices and ventrolateral thalamic, and medial amygdalo-hippocampal subregions. Meta-analyses of functional imaging data indicate that cortical correlates of SES are centered on brain systems subserving sensorimotor functions, language, memory, and emotional processing. We further show that anatomical variation within a subset of these cortical regions partially mediates the positive association between SES and IQ. Finally, we identify neuroanatomical correlates of SES that exist above and beyond accompanying variation in IQ. Although SES is clearly a complex construct that likely relates to development through diverse, nondeterministic processes, our findings elucidate potential neuroanatomical mediators of the association between SES and cognitive outcomes.SIGNIFICANCE STATEMENT Childhood socioeconomic status (SES) has been associated with developmental disparities in mental health, cognitive ability, and academic achievement, but efforts to understand underlying SES-brain relationships are ongoing. Here, we leverage a unique developmental neuroimaging dataset to longitudinally map the associations between SES and regional brain anatomy at high spatiotemporal resolution. We find widespread associations between SES and global cortical and subcortical volumes and surface area and localize these correlations to a distributed set of cortical, thalamic, and amygdalo-hippocampal subregions. Anatomical variation within a subset of these regions partially mediates the positive relationship between SES and IQ. Our findings help to localize cortical and subcortical systems that represent candidate biological substrates for the known relationships between SES and cognition.

Interaction between Socioeconomic Status and Cognitive Development in Children Aged 7, 9, and 11 Years: A Cross-Sectional Study

The socioeconomic status (SES) of parents has a crucial influence on the cognitive development of children, but it is not clear whether this effect varies as a function of the children's age. The objective of this study was to investigate the development of children aged 7, 9, and 11 years of parents with extremely low SES in a developing country (Ecuador). Participating children were divided between a medium-SES group and a low-SES group. Statistically significant differences were observed as a function of SES group and age in verbal memory, language, and executive function, observing wider between-group differences among the 11-year-olds.

Default Mode Network Maturation and Environmental Adversities During Childhood

Default mode network (DMN) plays a central role in cognition and brain disorders. It has been shown that adverse environmental conditions impact neurodevelopment, but how these conditions impact in DMN maturation is still poorly understood. This article reviews representative neuroimaging functional studies addressing the interactions between DMN development and environmental factors, focusing on early life adversities, a critical period for brain changes. Studies focused on this period of life offer a special challenge: to disentangle the neurodevelopmental connectivity changes from those related to environmental conditions. We first summarized the literature on DMN maturation, providing an overview of both typical and atypical development patterns in childhood and early adolescence. Afterward, we focused on DMN changes associated with chronic exposure to environmental adversities during childhood. This summary suggests that changes in DMN development could be a potential allostatic neural feature associated with an embodiment of environmental circumstances. Finally, we discuss about some key methodological issues that should be considered in paradigms addressing environmental adversities and open questions for future investigations.

The independent and interacting effects of socioeconomic status and dual-language use on brain structure and cognition

Family socioeconomic status (SES) is strongly associated with children's cognitive development, and past studies have reported socioeconomic disparities in both neurocognitive skills and brain structure across childhood. In other studies, bilingualism has been associated with cognitive advantages and differences in brain structure across the lifespan. The aim of the current study is to concurrently examine the joint and independent associations between family SES and dual-language use with brain structure and cognitive skills during childhood. A subset of data from the Pediatric Imaging, Neurocognition and Genetics (PING) study was analyzed; propensity score matching established an equal sample (N = 562) of monolinguals and dual-language users with similar socio-demographic characteristics (Mage = 13.5, Range = 3-20 years). When collapsing across all ages, SES was linked to both brain structure and cognitive skills. When examining differences by age group, brain structure was significantly associated with both income and dual-language use during adolescence, but not earlier in childhood. Additionally, in adolescence, a significant interaction between dual-language use and SES was found, with no difference in cortical surface area (SA) between language groups of higher-SES backgrounds but significantly increased SA for dual-language users from lower-SES families compared to SES-matched monolinguals. These results suggest both independent and interacting associations between SES and dual-language use with brain development. To our knowledge, this is the first study to concurrently examine dual-language use and socioeconomic differences in brain structure during childhood and adolescence.

Language development and disorders: Possible genes and environment interactions

Language development requires both basic cognitive mechanisms for learning language and a rich social context from which learning takes off. Disruptions in learning mechanisms, processing abilities, and/or social interactions increase the risks associated with social exclusion or developmental delays. Given the complexity of language processes, a multilevel approach is proposed where both cognitive mechanisms, genetic and environmental factors need to be probed together with their possible interactions. Here we review and discuss such interplay between environment and genetic predispositions in understanding language disorders, with a particular focus on a possible endophenotype, the ability for statistical sequential learning.

Dorsolateral prefrontal cortex volume as a mediator between socioeconomic status and executive function

OBJECTIVE

Lower socioeconomic status (SES) is related to poorer cognitive performance, but the neural underpinnings of this relation are not fully understood. This study examined whether SES-linked decrements in executive function were mediated by smaller dorsolateral prefrontal cortex (DLPFC) volumes. Given the literature demonstrating that SES-brain relations differ by race, we examined whether race moderated these mediations.

METHOD

Participants were 190 socioeconomically diverse, self-identified African American (AA) and White adults from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Regional brain volumes were derived using T1-weighted MP-RAGE images. Adjusting for age and sex, moderated mediation analyses examined if the DLPFC mediated SES-executive function relations differently across racial groups. Executive function was measured using Trail Making Test part B (Trails B), Digit Span Backwards (DSB), and verbal fluency.

RESULTS

Moderated mediation demonstrated that DLPFC volume significantly mediated the association between SES and Trails B in Whites (lower confidence interval [CI] = 0.01; upper CI = 0.07), but not in AAs (lower CI = -0.05; upper CI = 0.01). No mediations were found for DSB or verbal fluency, although SES was related to all tests.

CONCLUSION

The DLPFC may be important in the association of SES and mental flexibility for White, but not AA adults. It is possible that the well-replicated advantages of high SES among Whites do not readily translate, on average, to AAs. These findings highlight the importance of brain volume for cognitive functioning, while adding to the literature on sociodemographic health disparities. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Childhood Brain Development, the Educational Achievement Gap, and Cognitive Enhancement

Research on the effects of adversity on the brain of children initially encountered strong skepticism mainly due to the fear of stigmatization and the potential pathologizing of poverty as a disease. Despite initial resistance, an increasing body of work demonstrates a correlation between low socioeconomic status and brain development. This article will focus specifically on the impact of poverty (material, economic, and social) on childhood brain development and educational achievement. Some suggest that the use of cognitive enhancers in healthy students is perfectly acceptable and should be promoted to counterbalance the failure of traditional means to improve educational achievements. In this article, I critically assess the claim that a broad use of cognitive enhancers should be promoted and offer an alternative approach. The first section evaluates the neuroscientific facts and evidence of the impact of poverty on brain development and outlines some of the criticisms raised against the “neuroscience of poverty.” The second section focuses on the proposal made by Ray (2016) that promotes the use of cognitive enhancers as a means to address poor educational attainment. I criticize the basis of her argument and propose a different approach I call the clinical ideal. Subsequently, I provide some ethical pointers to allow an ethical and prudent use of cognitive enhancers in the educational setting. The main point of the article is not to reject prima facie the use of cognitive enhancers in socially disadvantaged students but rather provide a more nuanced approach.

Imaging Evidence of the Effect of Socio-Economic Status on Brain Structure and Development

Numerous studies have shown an association between children's socio-economic status (SES) and disparities in neurocognitive development, achievements, and function later in life. Research focus has recently shifted to imaging of the brain's response to the child's environment. This review summarizes the emerging studies on the influences of early-life SES on brain structure and development, and addresses the relation between brain development and enriched environments. The studies provide evidence of significant associations between SES and brain structure, growth and maturation, not only in healthy infants and children but also in infants with medical conditions. This suggests that the relation between SES and later-life function and achievements operates through alterations in brain maturation. Although the brain changes seem to persist without intervention, animal models of environmental enrichment show the potential of SES-related brain changes to be reversible and dynamic. This review underscores the critical need for reducing the impact of socio-economic disparities and early targeted and prolonged interventions, and highlights the potential of these interventions leading to optimal opportunities for our youngest.

The relationship between socioeconomic status and white matter microstructure in pre-reading children: A longitudinal investigation

Reading is a learned skill crucial for educational attainment. Children from families of lower socioeconomic status (SES) tend to have poorer reading performance and this gap widens across years of schooling. Reading relies on the orchestration of multiple neural systems integrated via specific white-matter pathways, but there is limited understanding about whether these pathways relate differentially to reading performance depending on SES background. Kindergarten white-matter FA and second-grade reading outcomes were investigated in an SES-diverse sample of 125 children. The three left-hemisphere white-matter tracts most associated with reading, and their right-hemisphere homologs, were examined: arcuate fasciculus (AF), superior longitudinal fasciculus (SLF), and inferior longitudinal fasciculus (ILF). There was a significant and positive association between SES and fractional anisotropy (FA) in the bilateral ILF in kindergarten. SES moderated the association between kindergarten ILF and second grade reading performance, such that it was positive in lower-SES children, but not significant in higher-SES children. These results have implications for understanding the role of the environment in the development of the neural pathways that support reading.

Subcortical brain volumes, cortical thickness and cortical surface area in families genetically enriched for social anxiety disorder - A multiplex multigenerational neuroimaging study

BACKGROUND

Social anxiety disorder (SAD) is a disabling psychiatric condition with a genetic background. Brain alterations in gray matter (GM) related to SAD have been previously reported, but it remains to be elucidated whether GM measures are candidate endophenotypes of SAD. Endophenotypes are measurable characteristics on the causal pathway from genotype to phenotype, providing insight in genetically-based disease mechanisms. Based on a review of existing evidence, we examined whether GM characteristics meet two endophenotype criteria, using data from a unique sample of SAD-patients and their family-members of two generations. First, we investigated whether GM characteristics co-segregate with social anxiety within families genetically enriched for SAD. Secondly, heritability of the GM characteristics was estimated.

METHODS

Families with a genetic predisposition for SAD participated in the Leiden Family Lab study on SAD; T1-weighted MRI brain scans were acquired (n = 110, 8 families). Subcortical volumes, cortical thickness and cortical surface area were determined for a-priori determined regions of interest (ROIs). Next, associations with social anxiety and heritabilities were estimated.

FINDINGS

Several subcortical and cortical GM characteristics, derived from frontal, parietal and temporal ROIs, co-segregated with social anxiety within families (uncorrected p-level) and showed moderate to high heritability.

INTERPRETATION

These findings provide preliminary evidence that GM characteristics of multiple ROIs, which are distributed over the brain, are candidate endophenotypes of SAD. Thereby, they shed light on the genetic vulnerability for SAD. Future research is needed to confirm these results and to link them to functional brain alterations and to genetic variations underlying these GM changes. FUND: Leiden University Research Profile 'Health, Prevention and the Human Life Cycle'.

Socioeconomic diversities and infant development at 6 to 9 months in a poverty area of São Paulo, Brazil

Abstract Introduction The effects of socioeconomic disparities on cognitive development tend to emerge early in infancy and to widen throughout childhood, and may perpetuate later in life. Although the study of how poverty affects early childhood has increased in the last 20 years, many of the effects remain largely unknown, especially during the first year of life. Aim To investigate the influence of socioeconomic status (SES) and maternal education on infants’ language, motor and cognitive development. Methods The cognitive, language and motor skills of 444 infants aged 6 to 9 months selected from a poor neighborhood in São Paulo, Brazil, were evaluated using the Bayley Scales of Infant Development. A questionnaire on socioeconomic background was administered to the participants’ families. Results A positive association was found between SES and infants’ performance on language and motor scales. Additionally, higher maternal education was associated with higher language and cognitive scores. Conclusion Our findings indicate that SES effects are detectable very early in infancy. This result has implications for the timing of both screening and intervention efforts to help children overcome the consequences of living in poverty.

Different Behavioral Experiences Produce Distinctive Parallel Changes in, and Correlate With, Frontal Cortex and Hippocampal Global Post-translational Histone Levels

While it is clear that behavioral experience modulates epigenetic profiles, it is less evident how the nature of that experience influences outcomes and whether epigenetic/genetic "biomarkers" could be extracted to classify different types of behavioral experience. To begin to address this question, male and female mice were subjected to either a Fixed Interval (FI) schedule of food reward, or a single episode of forced swim followed by restraint stress, or no explicit behavioral experience after which global expression levels of two activating (H3K9ac and H3K4me3) and two repressive (H3K9me2 and H3k27me3) post-translational histone modifications (PTHMs), were measured in hippocampus (HIPP) and frontal cortex (FC). The specific nature of the behavioral experience differentiated profiles of PTHMs in a sex- and brain region-dependent manner, with all 4 PTHMs changing in parallel in response to different behavioral experiences. These different behavioral experiences also modified the pattern of correlations of PTHMs both within and across FC and HIPP. Unexpectedly, highly robust correlations were found between global PTHM levels and behavioral performances, suggesting that global PTHMs may provide a higher-order pattern recognition function. Further efforts are needed to determine the generality of such findings and what characteristics of behavioral experience are critical for modulating PTHM responses.

Integrating Biomarkers in Social Stratification and Health Research

This article provides an overview of the integration of biomarkers and biological mechanisms in social science models of stratification and health. The goal in reviewing this literature is to highlight research that identifies the social forces that drive inequalities over the life course and across generations. The article is structured in the following way. First, descriptive background information on biomarkers is presented, followed secondly by a review of the general theoretical paradigms that lend themselves to an integrative approach. Third, the biomarkers used to capture several biological systems that are most responsive to social conditions are described. Fourth, research that explicates how social exposures "get under the skin" to affect physiological functioning and downstream health is discussed, using socioeconomic disadvantage as an illustrative social exposure. The review ends with emerging directions in the use of biomarkers in social science research. This article endeavors to encourage sociologists to embrace biosocial approaches in order to elevate the importance of social factors in biomedical processes and to intervene on the social conditions that create inequities.

The Predictive Value of Head Circumference Growth during the First Year of Life on Early Child Traits

Atypical head circumference (HC) growth has been associated with neurodevelopmental disorders. However, whether it is associated with specific aspects of development in early childhood in the general population is unknown. The objective of this study was to assess the predictive value of HC growth as an early biomarker of behavioral traits. We examined longitudinal associations between HC growth from 0 to 12 months and temperament, cognitive, and motor development at 24 months. A subsample of healthy children (N = 756) was drawn from the 3D (Design, Develop, Discover) cohort study. Early HC growth was modeled with latent growth curve analysis. Greater postnatal HC growth predicted lower temperamental effortful control and lower surgency/extraversion in boys. HC growth did not predict cognitive or fine motor scores, but did predict greater gross motor skills in boys. No significant effect of HC growth was found in girls. This study is the first to demonstrate an association between postnatal HC growth and specific aspects of child development in a healthy population. Results suggest HC growth overshadows brain mechanisms involved in behavioral traits in early infancy. Whether links are maintained throughout development and the mechanisms involved correspond to traits found in atypical populations remains to be studied.

How Social Status Shapes Person Perception and Evaluation: A Social Neuroscience Perspective

Inferring the relative rank (i.e., status) of others is essential to navigating social hierarchies. A survey of the expanding social psychological and neuroscience literatures on status reveals a diversity of focuses (e.g., perceiver vs. agent), operationalizations (e.g., status as dominance vs. wealth), and methodologies (e.g., behavioral, neuroscientific). Accommodating this burgeoning literature on status in person perception, the present review offers a novel social neuroscientific framework that integrates existing work with theoretical clarity. This framework distinguishes between five key concepts: (1) strategic pathways to status acquisition for agents, (2) status antecedents (i.e., perceptual and knowledge-based cues that confer status rank), (3) status dimensions (i.e., domains in which an individual may be ranked, such as wealth), (4) status level (i.e., one's rank along a given dimension), and (5) the relative importance of a given status dimension, dependent on perceiver and context characteristics. Against the backdrop of this framework, we review multiple dimensions of status in the nonhuman and human primate literatures. We then review the behavioral and neuroscientific literatures on the consequences of perceived status for attention and evaluation. Finally, after proposing a social neuroscience framework, we highlight innovative directions for future social status research in social psychology and neuroscience.

Community violence exposure in early adolescence: Longitudinal associations with hippocampal and amygdala volume and resting state connectivity

Community violence exposure is a common stressor, known to compromise youth cognitive and emotional development. In a diverse, urban sample of 22 adolescents, participants reported on community violence exposure (witnessing a beating or illegal drug use, hearing gun shots, or other forms of community violence) in early adolescence (average age 12.99), and underwent a neuroimaging scan 3-5 years later (average age 16.92). Community violence exposure in early adolescence predicted smaller manually traced left and right hippocampal and amygdala volumes in a model controlling for age, gender, and concurrent community violence exposure, measured in late adolescence. Community violence continued to predict hippocampus (but not amygdala) volumes after we also controlled for family aggression exposure in early adolescence. Community violence exposure was also associated with stronger resting state connectivity between the right hippocampus (using the manually traced structure as a seed region) and bilateral frontotemporal regions including the superior temporal gyrus and insula. These resting state connectivity results held after controlling for concurrent community violence exposure, SES, and family aggression. Although this is the first study focusing on community violence in conjunction with brain structure and function, these results dovetail with other research linking childhood adversity with smaller subcortical volumes in adolescence and adulthood, and with altered frontolimbic resting state connectivity. Our findings suggest that even community-level exposure to neighborhood violence can have detectable neural correlates in adolescents.

Threat vigilance and socioeconomic disparities in metabolic health

A quarter of the global population meets diagnostic criteria for metabolic syndrome (MetS). MetS prevalence stratifies by socioeconomic status (SES), such that low SES is associated with higher MetS risk starting in childhood. Despite this trend, some low-SES children maintain good metabolic health across the life span, but the factors responsible for their resilience are not well understood. This study examined the role of threat vigilance as either a moderator or a mediator of the effects of low early life SES on adult metabolic risk. Three hundred twenty-five Canadians aged 15-55 participated (M = 36.4 years, SD = 10.7; 55.4% female). We coded parental occupational status between the ages of 0 and 5 to index early life SES. We used the International Diabetes Federation case definition for MetS based on waist circumference, blood pressure, triglyceride levels, HDL cholesterol, and glycosylated hemoglobin measures. Threat vigilance was assessed using the Weapons Identification Procedure, a visual discrimination paradigm that captures implicit perceptions of threat. Analyses supported the moderator hypothesis: low early life SES was associated with MetS diagnosis exclusively among those with high levels of threat vigilance. This suggests that low early life SES environments that heighten vigilance to threat might be particularly detrimental for metabolic health. Conversely, low threat vigilance may buffer against the metabolic risks associated with socioeconomic disadvantage.

What Factors Facilitate Resilience in Developmental Dyslexia? Examining Protective and Compensatory Mechanisms Across the Neurodevelopmental Trajectory

Developmental dyslexia is a specific learning disability characterized by deficits reading single words. Dyslexia is heritable and has been associated with neural alterations in regions of the left hemisphere in the brain. Cognitive and neural atypicalities have been observed before children with familial risk for dyslexia begin reading, yet children who are at risk subsequently develop reading abilities on a continuum from good to poor. Of those children who develop good reading skills, what factors are associated with more successful outcomes? In this article, we review findings describing genetic, cognitive, neurobiological, and environmental factors that facilitate reading development and propose a model of neural pathways to support successful reading development in at-risk children. This research can inform educational and clinical strategies to support at-risk children. Investigating factors that contribute to the variance in behavioral outcomes among at-risk children may help us understand developmental disorders and associated etiological, compensatory, and protective factors.

Socioeconomic Position and Age-Related Disparities in Regional Cerebral Blood Flow Within the Prefrontal Cortex

OBJECTIVE

Socioeconomic position (SEP) is associated with cerebrovascular health and brain function, particularly in prefrontal cortex and medial temporal lobe regions that exhibit plasticity across the life course. However, it is unknown whether SEP associates with resting cerebral blood flow (CBF), an indicator of baseline brain function, in these regions in midlife, and whether the association is (a) period specific, with independent associations for childhood and adulthood SEP, or driven by life course SEP, and (b) explained by a persistent disparity, widening disparity, or the leveling of disparities with age.

METHODS

To address these questions, we analyzed cerebral perfusion derived by magnetic resonance imaging in a cross-sectional study of healthy adults (N = 443) who reported on childhood and adult SEP. Main effects were examined as an index of persistent disparity and age by SEP interactions as reflecting widening or leveling disparities.

RESULTS

Stable high SEP across the lifespan was associated with higher global CBF and regional CBF (rCBF) in inferior frontal gyrus. However, childhood SEP was associated with rCBF in middle frontal gyrus, as moderated by age (β = 0.04, p = .035): rCBF was inversely associated with age only for those whose parents had a high school education or below. No associations were observed for the hippocampus or amygdala.

CONCLUSIONS

Life course SEP associations with rCBF in prefrontal cortex are suggestive of persistent disparities, whereas the age by childhood SEP interaction suggests that childhood disadvantage relates to a widening disparity, independent of global differences. These differential patterns in midlife may relate to disparities in later-life cerebrovascular and neurocognitive outcomes.

Income change alters default mode network connectivity for adolescents in poverty

Experiencing poverty during childhood and adolescence may affect brain function. However, income is dynamic, and studies have not addressed whether income change relates to brain function. In the present study, we investigated whether intrinsic functional connectivity of default mode network (DMN) regions was influenced by mean family income and family income change. Parents of 68 Mexican-origin adolescents (35 females) reported family income annually when adolescents were 10-16 years old. Intercept and slope of income at each of these ages were calculated for each participant. At age 16 years, adolescents completed a resting state functional neuroimaging scan. Adolescents from high and low income families did not differ in their functional connectivity, but for adolescents in families with lower incomes, their connectivity patterns depended on their income slope. Low-income adolescents whose income increased demonstrated greater connectivity between the posterior cingulate cortex (PCC) and the medial prefrontal cortex (mPFC), both DMN regions, and between the PCC and the right inferior frontal gyrus. Increases in income were associated with greater connectivity of the mPFC with the right inferior frontal gyrus and the left superior parietal lobule regardless of mean income. Increases in income, especially among adolescents in poverty, may alleviate stressors, influencing the development of brain networks.

Time-varying effects of income on hippocampal volume trajectories in adolescent girls

Children from lower-SES families exhibit smaller hippocampal volume than do their higher-SES peers. Few studies, however, have compared hippocampal developmental trajectories as a function of SES. Thus, it is unclear whether initial rank-order stability is preserved, or whether volumes diverge/converge over the course of adolescence. In a sample of 101 girls ages 10-24 years, we examined the longitudinal association between family income and parental education, proxies for SES, and changes in hippocampal volume. Hippocampal volume was obtained using MRI; using mixed modeling, we examined the effects of income and education on hippocampal volume across age. As expected, changes in volume were non-linear across development. Further, trajectories diverged in mid-adolescence, with lower-income girls exhibiting reductions in hippocampal volume. Maximal income-related differences were observed at 18 years, and trajectories converged thereafter. This interaction remained significant when accounting for maternal hippocampal volume, suggesting a unique contribution of environment over potential heritable differences. In contrast, the association between parental education and offspring hippocampal volume appeared to be stable across adolescence, with higher levels of parental education predicting consistently larger hippocampal volume. These findings constitute preliminary evidence that girls from lower-income homes exhibit unique trajectories of hippocampal growth, with differences most evident in late adolescence.

Predicting age from cortical structure across the lifespan

Despite interindividual differences in cortical structure, cross-sectional and longitudinal studies have demonstrated a large degree of population-level consistency in age-related differences in brain morphology. This study assessed how accurately an individual's age could be predicted by estimates of cortical morphology, comparing a variety of structural measures, including thickness, gyrification and fractal dimensionality. Structural measures were calculated across up to seven different parcellation approaches, ranging from one region to 1000 regions. The age prediction framework was trained using morphological measures obtained from T1-weighted MRI volumes collected from multiple sites, yielding a training dataset of 1056 healthy adults, aged 18-97. Age predictions were calculated using a machine-learning approach that incorporated nonlinear differences over the lifespan. In two independent, held-out test samples, age predictions had a median error of 6-7 years. Age predictions were best when using a combination of cortical metrics, both thickness and fractal dimensionality. Overall, the results reveal that age-related differences in brain structure are systematic enough to enable reliable age prediction based on metrics of cortical morphology.

Socioeconomic disparities in academic achievement: A multi-modal investigation of neural mechanisms in children and adolescents

Growing evidence suggests that childhood socioeconomic status (SES) influences neural development, which may contribute to the well-documented SES-related disparities in academic achievement. However, the particular aspects of SES that impact neural structure and function are not well understood. Here, we investigate associations of childhood SES and a potential mechanism-degree of cognitive stimulation in the home environment-with cortical structure, white matter microstructure, and neural function during a working memory (WM) task across development. Analyses included 53 youths (age 6-19 years). Higher SES as reflected in the income-to-needs ratio was associated with higher parent-reported achievement, WM performance, and cognitive stimulation in the home environment. Although SES was not significantly associated with cortical thickness, children raised in more cognitively stimulating environments had thicker cortex in the frontoparietal network and cognitive stimulation mediated the assocation between SES and cortical thickness in the frontoparietal network. Higher family SES was associated with white matter microstructure and neural activation in the frontoparietal network during a WM task, including greater fractional anisotropy (FA) in the right and left superior longitudinal fasciculi (SLF), and greater BOLD activation in multiple regions of the prefrontal cortex during WM encoding and maintenance. Greater FA and activation in these regions was associated higher parent-reported achievement. Together, cognitive stimulation, WM performance, FA in the SLF, and prefrontal activation during WM encoding and maintenance significantly mediated the association between SES and parent-reported achievement. These findings highlight potential neural, cognitive, and environmental mechanisms linking SES with academic achievement and suggest that enhancing cognitive stimulation in the home environment might be one effective strategy for reducing SES-related disparities in academic outcomes.

Imaging structural and functional brain development in early childhood

In humans, the period from term birth to ∼2 years of age is characterized by rapid and dynamic brain development and plays an important role in cognitive development and risk of disorders such as autism and schizophrenia. Recent imaging studies have begun to delineate the growth trajectories of brain structure and function in the first years after birth and their relationship to cognition and risk of neuropsychiatric disorders. This Review discusses the development of grey and white matter and structural and functional networks, as well as genetic and environmental influences on early-childhood brain development. We also discuss initial evidence regarding the usefulness of early imaging biomarkers for predicting cognitive outcomes and risk of neuropsychiatric disorders.

Reading skill-fractional anisotropy relationships in visuospatial tracts diverge depending on socioeconomic status

Low socioeconomic status (SES) has been repeatedly linked with decreased academic achievement, including lower reading outcomes. Some lower SES children do show skills and scores commensurate with those of their higher SES peers, but whether their abilities stem from the same systems as high SES children or are based on divergent strategies is unknown. We here investigated a potential interactive relationship between SES and real-word reading skill in the white matter in 42 typically developing children. SES was determined based on parental education; reading skill and age were not significantly related to SES. There was a significant neural interaction: Clusters in the bilateral inferior longitudinal fasciculus (ILF), left superior longitudinal fasciculus, and left corticospinal tract demonstrated interactive skill-SES relationships in fractional anisotropy. Follow-up analyses demonstrated that higher SES children showed a positive relationship between fractional anisotropy, reflecting tract coherence, and reading skill in left hemisphere tract clusters, whereas lower SES children showed a positive relationship in the right hemisphere homologues. Broadly, the ILF has been demonstrated to support orthographic skill on the left and more general visuospatial processing on the right, so high reading achievement in lower SES children may rely on supplementary visuospatial processing more than for higher SES readers. This pattern is consistent with previous work reporting low SES children's environments to include less rich verbal experience, which may lead them to disproportionately draw on visuospatial skills for success. Further, these results indicate that group SES differences may be best described by an adaptive, not a deficit, model.