Material hardship, prefrontal cortex-amygdala structure, and internalizing symptoms in children

The ecology of poverty and children's brain development: A systematic review and quantitative meta-analysis of brain imaging studies

A growing number of studies have demonstrated associations between poverty and brain structure and function. However, the strength of this association and the effects of poverty level (e.g., family or neighborhood poverty), age and sex on the association are strikingly inconsistent across studies. We aimed to synthesize findings on gray matter volume and task-based brain activation associated with poverty in youth samples and disentangle the effects of poverty level, age, and sex. In general, poverty was associated with alterations in volume and activation in the frontal, temporal, and subcortical regions. Among 14,188 participants and 14,057 participants, poverty was associated with smaller gray matter volumes in the amygdala and hippocampus, respectively. Moderator testing revealed that family poverty had a stronger association than neighborhood poverty and that poverty was related to slower development of amygdala volume. Among 2696 participants, convergent functional alterations associated with poverty were observed in the left middle temporal gyrus (MTG) and left middle frontal gyrus across all task domains, with the percentage of girls positively associated with increased activation in the precuneus. Subgroup analyses revealed that greater poverty was associated with deactivation in the left MTG for top-down control and hyperactivity in the right superior temporal gyrus, left superior frontal gyrus, left insula, cerebellum/left fusiform gyrus, and left amygdala/hippocampus for bottom-up processing. These findings provide insights into the neuroscience of poverty, suggesting implications for targeted interventions to support the cognitive and mental health of children living in poverty.

Material Hardship Predicts Response Bias in Loss-Averse Decisions: The Roles of Anxiety and Cognitive Control

Income poverty is associated with an enhanced tendency to avoid losses in economic decisions, which can be driven by a response bias (risk avoidance) and a valuation bias (loss aversion). However, the impact of non-income dimensions of poverty on these biases remains unclear. The current study tested the impact of material hardship on these biases, and the mediating effects of anxiety, depression, and cognitive control in these associations. Healthy adults (N = 188) completed questionnaire and behavioral measures of the variables. Results of regression-based analyses showed that participants who reported higher material hardship exhibited greater response bias, but not valuation bias. This effect was mediated by anxiety. Although material hardship predicted lower cognitive control, cognitive control did not mediate the association between material hardship and either type of bias. These findings suggest that material hardship may lead to economic decision-making biases because it impacts emotional states rather than cognitive control.

Socioeconomic Disparities in Hypothalamic-Pituitary-Adrenal Axis Regulation and Prefrontal Cortical Structure

Socioeconomic disadvantage during childhood predicts an increased risk for mental health problems across the life span. Socioeconomic disadvantage shapes multiple aspects of children's proximal environments and increases exposure to chronic stressors. Drawing from multiple literatures, we propose that childhood socioeconomic disadvantage may lead to adaptive changes in the regulation of stress response systems including the hypothalamic-pituitary-adrenal (HPA) axis. These changes, in turn, affect the development of prefrontal cortical (PFC) circuitry responsible for top-down control over cognitive and emotional processes. Translational findings indicate that chronic stress reduces dendritic complexity and spine density in the medial PFC and anterior cingulate cortex, in part through altered HPA axis regulation. Socioeconomic disadvantage has frequently been associated with reduced gray matter in the dorsolateral and ventrolateral PFC and anterior cingulate cortex and lower fractional anisotropy in the superior longitudinal fasciculus, cingulum bundle, and uncinate fasciculus during middle childhood and adolescence. Evidence of socioeconomic disparities in hair cortisol concentrations in children has accumulated, although null findings have been reported. Coupled with links between cortisol levels and reduced gray matter in the PFC and anterior cingulate cortex, these results support mechanistic roles for the HPA axis and these PFC circuits. Future longitudinal studies should simultaneously consider multiple dimensions of proximal factors, including cognitive stimulation, while focusing on epigenetic processes and genetic moderators to elucidate how socioeconomic context may influence the HPA axis and PFC circuitry involved in cognitive and emotional control. These findings, which point to modifiable factors, can be harnessed to inform policy and more effective prevention strategies.

Prenatal and Postnatal Maternal Depressive Symptoms Are Associated With White Matter Integrity in 5-Year-Olds in a Sex-Specific Manner

BACKGROUND

Prenatal and postnatal maternal psychological distress predicts various detrimental consequences on social, behavioral, and cognitive development of offspring, especially in girls. Maturation of white matter (WM) continues from prenatal development into adulthood and is thus susceptible to exposures both before and after birth.

METHODS

WM microstructural features of 130 children (mean age, 5.36 years; range, 5.04-5.79 years; 63 girls) and their association with maternal prenatal and postnatal depressive and anxiety symptoms were investigated with diffusion tensor imaging, tract-based spatial statistics, and regression analyses. Maternal questionnaires were collected during first, second, and third trimesters and at 3, 6, and 12 months postpartum with the Edinburgh Postnatal Depression Scale (EPDS) for depressive symptoms and Symptom Checklist-90 for general anxiety. Covariates included child's sex; child's age; maternal prepregnancy body mass index; maternal age; socioeconomic status; and exposures to smoking, selective serotonin reuptake inhibitors, and synthetic glucocorticoids during pregnancy.

RESULTS

Prenatal second-trimester EPDS scores were positively associated with fractional anisotropy in boys (p < .05, 5000 permutations) after controlling for EPDS scores 3 months postpartum. In contrast, postpartum EPDS scores at 3 months correlated negatively with fractional anisotropy (p < .01, 5000 permutations) in widespread areas only in girls after controlling for prenatal second-trimester EPDS scores. Perinatal anxiety was not associated with WM structure.

CONCLUSIONS

These results suggest that prenatal and postnatal maternal psychological distress is associated with brain WM tract developmental alterations in a sex- and timing-dependent manner. Future studies including behavioral data are required to consolidate associative outcomes for these alterations.

Early life stress, prenatal secondhand smoke exposure, and the development of internalizing symptoms across childhood

BACKGROUND

Prior findings relating secondhand tobacco smoke (SHS) exposure and internalizing problems, characterized by heightened anxiety and depression symptoms, have been equivocal; effects of SHS on neurodevelopment may depend on the presence of other neurotoxicants. Early life stress (ELS) is a known risk factor for internalizing symptoms and is also often concurrent with SHS exposure. To date the interactive effects of ELS and SHS on children's internalizing symptoms are unknown. We hypothesize that children with higher exposure to both prenatal SHS and ELS will have the most internalizing symptoms during the preschool period and the slowest reductions in symptoms over time.

METHODS

The present study leveraged a prospective, longitudinal birth cohort of 564 Black and Latinx mothers and their children, recruited between 1998 and 2006. Cotinine extracted from cord and maternal blood at birth served as a biomarker of prenatal SHS exposure. Parent-reported Child Behavior Checklist (CBCL) scores were examined at four timepoints between preschool and eleven years-old. ELS exposure was measured as a composite of six domains of maternal stress reported at child age five. Latent growth models examined associations between SHS, ELS, and their interaction term with trajectories of children's internalizing symptoms. In follow-up analyses, weighted quintile sum regression examined contributions of components of the ELS mixture to children's internalizing symptoms at each time point.

RESULTS

ELS interacted with SHS exposure such that higher levels of ELS and SHS exposure were associated with more internalizing symptoms during the preschool period (β = 0.14, p = 0.03). The interaction between ELS and SHS was also associated with a less negative rate of change in internalizing symptoms over time (β=-0.02, p = 0.01). Weighted quintile sum regression revealed significant contributions of maternal demoralization and other components of the stress mixture to children's internalizing problems at each age point (e.g., age 11 WQS β = 0.26, p < 0.01).

CONCLUSIONS

Our results suggest that prior inconsistencies in studies of SHS on behavior may derive from unmeasured factors that also influence behavior and co-occur with exposure, specifically maternal stress during children's early life. Findings point to modifiable targets for personalized prevention.

Profiles of Early Childhood Adversity in an Urban Pediatric Clinic: Implications for Pediatric Primary Care

Pediatricians are well-positioned to screen for early childhood adversities, but effective responses to positive screens require an understanding of which adversities typically co-occur, and to what extent they are associated with other risk or protective factors. Among children seen at an urban academic pediatric practice, this study aimed to (1) examine the prevalence of different types of early adversity and protective experiences reported by primary caregivers, and (2) define latent classes of co-occurring adversities. Of 1434 children whose parents completed the Safe Environment for Every Kid (SEEK) at well-child visits during November 2019-January 2021, three classes of adverse experiences emerged, including those reporting low adversity (L; 73%), caregiver stress (CS; 17%), and both caregiver stress and depression (CSD; 10%). Among those who also completed the Adverse Childhood Experiences Questionnaire (ACE-Q, n = 1373) and the Protective and Compensatory Experiences Scale (PACES, n = 1377), belonging to the L class was associated with lower ACE-Q and higher PACES scores. For parent-respondents only, ACE-Q scores were significantly greater for the CSD class compared to the CS and L classes. Pediatricians should attend to the needs of caregivers reporting both stress and depression, as these families may face especially high levels of adversity and low levels of protective factors.

Differential Developmental Associations of Material Hardship Exposure and Adolescent Amygdala-Prefrontal Cortex White Matter Connectivity

Accumulating literature has linked poverty to brain structure and function, particularly in affective neural regions; however, few studies have examined associations with structural connections or the importance of developmental timing of exposure. Moreover, prior neuroimaging studies have not used a proximal measure of poverty (i.e., material hardship, which assesses food, housing, and medical insecurity) to capture the lived experience of growing up in harsh economic conditions. The present investigation addressed these gaps collectively by examining the associations between material hardship (ages 1, 3, 5, 9, and 15 years) and white matter connectivity of frontolimbic structures (age of 15 years) in a low-income sample. We applied probabilistic tractography to diffusion imaging data collected from 194 adolescents. Results showed that material hardship related to amygdala-prefrontal, but not hippocampus-prefrontal or hippocampus-amygdala, white matter connectivity. Specifically, hardship during middle childhood (ages 5 and 9 years) was associated with greater connectivity between the amygdala and dorsomedial pFC, whereas hardship during adolescence (age of 15 years) was related to reduced amygdala-orbitofrontal (OFC) and greater amygdala-subgenual ACC connectivity. Growth curve analyses showed that greater increases of hardship across time were associated with both greater (amygdala-subgenual ACC) and reduced (amygdala-OFC) white matter connectivity. Furthermore, these effects remained above and beyond other types of adversity, and greater hardship and decreased amygdala-OFC connectivity were related to increased anxiety and depressive symptoms. Results demonstrate that the associations between material hardship and white matter connections differ across key prefrontal regions and developmental periods, providing support for potential windows of plasticity for structural circuits that support emotion processing.

Socioeconomic factors, stress, hair cortisol, and white matter microstructure in children

Socioeconomic disadvantage has been linked to increased stress exposure in children and adults. Exposure to stress in childhood has been associated with deleterious effects on cognitive development and well-being throughout the lifespan. Further, exposure to stress has been associated with differences in brain development in children, both in cortical and subcortical gray matter. However, less is known about the associations among socioeconomic disadvantage, stress, and children's white matter development. In this study, we investigated whether socioeconomic disparities would be associated with differences in white matter microstructure in the cingulum bundle, as has been previously reported. We additionally investigated whether any such differences could be explained by differences in stress exposure and/or physiological stress levels. White matter tracts were measured via diffusion tensor imaging in 58 children aged 5-9 years. Results indicated that greater exposure to stressful life events was associated with higher child hair cortisol concentrations. Further, physiological stress, as indexed by hair cortisol concentrations, were associated with higher fractional anisotropy in the cingulum bundle. These results have implications for better understanding how perceived and physiological stress may alter neural development during childhood.