Human brain development occurs within a socioeconomic context and childhood socioeconomic status (SES) influences neural development — particularly of the systems that subserve language and executive function. Research in humans and in animal models has implicated prenatal factors, parent–child interactions and cognitive stimulation in the home environment in the effects of SES on neural development. These findings provide a unique opportunity for understanding how environmental factors can lead to individual differences in brain development, and for improving the programmes and policies that are designed to alleviate SES-related disparities in mental health and academic achievement.

Childhood socioeconomic status (SES) is associated with cognitive achievement throughout life. How does SES relate to brain development, and what are the mechanisms by which SES might exert its influence? We review studies in which behavioral, electrophysio-logical and neuroimaging methods have been used to characterize SES disparities in neurocognitive function. These studies indicate that SES is an important predictor of neurocognitive performance, particularly of language and executive function, and that SES differences are found in neural processing even when performance levels are equal. Implications for basic cognitive neuroscience and for understanding and ameliorating the problems related to childhood poverty are discussed.

Childhood socioeconomic status (SES) predicts executive function (EF), but fundamental aspects of this relation remain unknown: the developmental course of the SES disparity, its continued sensitivity to SES changes during that course, and the features of childhood experience responsible for the SES-EF relation. Regarding course, early disparities would be expected to grow during development if caused by accumulating stressors at a given constant level of SES. Alternatively, they would narrow if schooling partly compensates for the effects of earlier deprivation, allowing lower-SES children to 'catch up'. The potential for later childhood SES change to affect EF is also unknown. Regarding mediating factors, previous analyses produced mixed answers, possibly due to correlation amongst candidate mediators. We address these issues with measures of SES, working memory and planning, along with multiple candidate mediators, from the NICHD Study of Early Childcare (n = 1009). Early family income-to-needs and maternal education predicted planning by first grade, and income-to-needs predicted working memory performance at 54 months. Effects of early SES remained consistent through middle childhood, indicating that the relation between early indicators of SES and EF emerges in childhood and persists without narrowing or widening across early and middle childhood. Changes in family income-to-needs were associated with significant changes in planning and trend-level changes in working memory. Mediation analyses supported the role of early childhood home characteristics in explaining the association between SES and EF, while early childhood maternal sensitivity was specifically implicated in the association between maternal education and planning. Early emerging and persistent SES-related differences in EF, partially explained by characteristics of the home and family environment, are thus a potential source of socioeconomic disparities in achievement and health across development.

Residing in communities of socioeconomic disadvantage confers risk for chronic diseases and cognitive aging, as well as risk for biological factors that negatively affect brain morphology. The present study tested whether community disadvantage negatively associates with brain morphology via 2 biological factors encompassing cardiometabolic disease risk and neuroendocrine function. Participants were 448 midlife adults aged 30-54 years (236 women) who underwent structural neuroimaging to assess cortical and subcortical brain tissue morphology. Community disadvantage was indexed by US Census data geocoded to participants' residential addresses. Cardiometabolic risk was indexed by measurements of adiposity, blood pressure, glucose, insulin, and lipids. Neuroendocrine function was indexed from salivary cortisol measurements taken over 3 days, from which we computed the cortisol awakening response, area-under-the-curve, and diurnal cortisol decline. Community disadvantage was associated with reduced cortical tissue volume, cortical surface area, and cortical thickness, but not subcortical morphology. Moreover, increased cardiometabolic risk and a flatter (dysregulated) diurnal cortisol decline mediated the associations of community disadvantage and cortical gray matter volume. These effects were independent of age, sex, and individual-level socioeconomic position. The adverse risks of residing in a disadvantaged community may extend to the cerebral cortex via cardiometabolic and neuroendocrine pathways.

Working memory (WM) is positively correlated with socioeconomic status (SES). It is not clear, however, if SES predicts the rate of WM development over time nor whether SES effects are specific to family rather than neighborhood SES. A community sample of children (n = 316) enrolled between ages 10 and 13 completed four annual assessments of WM. Lower parental education, but not neighborhood disadvantage, was associated with worse WM performance. Neither measure of SES was associated with the rate of developmental change. Consequently the SES disparity in WM is not a developmental lag which narrows nor an accumulating effect that becomes more pronounced. Rather, the relation between family SES and WM originates earlier in childhood and is stable though adolescence.Working memory refers to the active, short-term maintenance and manipulation of information, generally in the service of guiding behavior, and is dependent on the prefrontal cortex (Baddeley, 2003;Best & Miller, 2010). Working memory becomes differentiated from single, overarching executive control processes by middle childhood and exhibits improvement through childhood and adolescence as the prefrontal cortex develops (Best & Miller, 2010; Lee, Bull, & Ho, in press). In the past decade the question of how social contexts, such as socioeconomic status, influence working memory performance and development has emerged as an increasing area of focus to explain individual differences in working memory development.This question also has considerable applied relevance. Working memory is a strong candidate mediator explaining the graded association between socioeconomic status (SES) and disparities in achievement, health and psychopathology (Adler et al., 1994;Bradley & Corwyn, 2002;Brooks-Gunn & Duncan, 1997;Sirin, 2005 NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript function of holding and integrating information, that working memory plays a critical role in a wide array of cognitive abilities (Kimberg & Farah, 1993), mathematical skills (Alloway & Alloway, 2010;Bull, Espy, & Wiebe, 2008) and reading comprehension (Alloway & Alloway, 2010;Daneman & Merikle, 1996), and thus is an important foundational ability for cognitive development and achievement. Additionally, working memory has also been associated with depression (Snyder, 2013), health behaviors such as nutrition and physical activity (Riggs, Chou, Spruijt-Metz, & Pentz, 2010), alcohol use (Houben, Wiers, & Jansen, 2011) and sexual debut (Khurana et al., 2012). Consequently, working memory is a plausible mediator that may account, at least in part, for a wide-range of SES-related disparities.SES can be measured by various indices such as family income, parental education, and neighborhood characteristics (Krieger, Williams, & Moss, 1997). It is generally correlated with child and family stress and parenting behavior (Bradley & Corwyn, 2002;Conger & Donnellan, 2007;Evans, 2004), factors which would be expected to impact the development of neurocognitive systems inclu...

Lower socioeconomic status (SES) is associated with higher levels of life stress, which in turn affect stress physiology. SES is related to basal cortisol and diurnal change, but it is not clear if SES is associated with cortisol reactivity to stress. To address this question, we examined the relationship between two indices of SES, parental education and concentrated neighborhood disadvantage, and the cortisol reactivity of African–American adolescents to a modified version of the Trier Social Stress Test (TSST). We found that concentrated disadvantage was associated with cortisol reactivity and this relationship was moderated by gender, such that higher concentrated disadvantage predicted higher cortisol reactivity and steeper recovery in boys but not in girls. Parental education, alone or as moderated by gender, did not predict reactivity or recovery, while neither education nor concentrated disadvantage predicted estimates of baseline cortisol. This finding is consistent with animal literature showing differential vulnerability, by gender, to the effects of adverse early experience on stress regulation and the differential effects of neighborhood disadvantage in adolescent males and females. This suggests that the mechanisms underlying SES differences in brain development and particularly reactivity to environmental stressors may vary across genders.

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IMPORTANCE Neighborhood disadvantage is an important social determinant of health in childhood and adolescence. Less is known about the association of neighborhood disadvantage with youth neurocognition and brain structure, and particularly whether associations are similar across metropolitan areas and are attributed to local differences in disadvantage.OBJECTIVE To test whether neighborhood disadvantage is associated with youth neurocognitive performance and with global and regional measures of brain structure after adjusting for family socioeconomic status and perceptions of neighborhood characteristics, and to assess whether these associations (1) are pervasive or limited, (2) vary across metropolitan areas, and (3) are attributed to local variation in disadvantage within metropolitan areas. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study analyzed baseline data from the Adolescent Brain and Cognitive Development (ABCD) Study, a cohort study conducted at 21 sites across the US. Participants were children aged 9.00 to 10.99 years at enrollment. They and their parent or caregiver completed a baseline visit between October 1, 2016, and October 31, 2018. EXPOSURES Neighborhood disadvantage factor based on US census tract characteristics. MAIN OUTCOMES AND MEASURES Neurocognition was measured with the NIH ToolboxCognition Battery, and T1-weighted magnetic resonance imaging was used to assess whole-brain and regional measures of structure. Linear mixed-effects models examined the association between neighborhood disadvantage and outcomes after adjusting for sociodemographic factors. RESULTSOf the 11 875 children in the ABCD Study cohort, 8598 children (72.4%) were included in this analysis. The study sample had a mean (SD) age of 118.8 (7.4) months and included 4526 boys (52.6%). Every 1-unit increase in the neighborhood disadvantage factor was associated with lower performance on 6 of 7 subtests, such as Flanker Inhibitory Control and Attention (unstandardized Β = −0.5; 95% CI, −0.7 to −0.2; false discovery rate (FDR)-corrected P = .001) and List Sorting Working Memory (unstandardized Β = −0.7; 95% CI, −1.0 to −0.3; FDR-corrected P < .001), as well as on all composite measures of neurocognition, such as the Total Cognition Composite (unstandardized Β = −0.7; 95% CI, −0.9 to −0.5; FDR-corrected P < .001). Each 1-unit increase in neighborhood disadvantage was associated with lower whole-brain cortical surface area (unstandardized Β = −692.6 mm 2 ; 95% CI, −1154.9 to −230.4 mm 2 ; FDR-corrected P = .007) and subcortical volume (unstandardized Β = −113.9 mm 3 ; 95% CI, −198.5 to −29.4 mm 3 ; FDR-corrected P = .03) as well as with regional surface area differences, primarily in the frontal, parietal, and temporal lobes. Associations largely remained after adjusting for perceptions of neighborhood safety and were both consistent across metropolitan areas and primarily explained by local variation in each area.CONCLUSIONS AND RELEVANCE This study found that, in the US, local variation in neighborhood disadvant...