Neighborhood deprivation, prefrontal morphology and neurocognition in late childhood to early adolescence.

BACKGROUND: Neighborhood deprivation adversely effects neurodevelopment and cognitive function; however, mechanisms remain unexplored. Neighborhood deprivation could be particularly impactful in late childhood/early adolescence, in neural regions with protracted developmental trajectories, e.g., prefrontal cortex (PFC). METHODS: The Adolescent Brain Cognitive Development (ABCD) study recruited 10,205 youth. Geocoded residential history was used to extract individual neighborhood characteristics. A general cognitive ability index and MRI scans were completed. Associations with neurocognition were examined. The relation of PFC surface area and cortical thickness to neighborhood deprivation was tested. PFC subregions and asymmetry, with putative differential environmental susceptibility during key developmental periods, were explored. Analyses tested PFC area as a possible mediating mechanism. RESULTS: Neighborhood deprivation predicted neurocognitive performance (ߠ​= â€‹-0.11), even after accounting for parental education and household income (ߠ​= â€‹-0.07). Higher neighborhood deprivation related to greater overall PFC surface area (ηp2 â€‹= â€‹0.003), and differences in leftward asymmetry were observed for area (ηp2 â€‹= â€‹0.001), and thickness (ηp2 â€‹= â€‹0.003). Subregion analyses highlighted differences among critical areas that are actively developing in late childhood/early adolescence and are essential to modulating high order cognitive function. These included orbitofrontal, superior frontal, rostral middle frontal, and frontal pole regions (Cohen's d â€‹= â€‹0.03-0.09). PFC surface area partially mediated the relation between neighborhood deprivation and neurocognition. DISCUSSION: Neighborhood deprivation related to cognitive function (a foundational skill tied to a range of lifetime outcomes) and PFC morphology, with evidence found for partial mediation of PFC on neurocognitive function. Results inform public health conceptualizations of development and environmental vulnerability.

The role of the visual association cortex in scaffolding prefrontal cortex development: A novel mechanism linking socioeconomic status and executive function.

Socioeconomic status (SES) is associated with executive function (EF) and prefrontal cortex (PFC) development. However, understanding of the specific aspects of SES that influence development of EF and the PFC remains limited. We briefly review existing literature on proposed mechanisms linking SES with EF. Then, we present a novel conceptual model arguing that early cognitive stimulation shapes EF and PFC development. We propose that cognitive stimulation drives lower-level sensory and perceptual processes that may impact EF and PFC development through reciprocal connections between the ventral visual stream and PFC. We argue that caregivers guide attention and associative learning, which provides children the opportunity to regulate attention and gain semantic knowledge. This experience in turn allows for opportunities to train the PFC to resolve conflict between stimuli with overlapping features and engage in increasingly complex computations as visual processing systems develop; this may lay the groundwork for development of EF. We review existing evidence for this model and end by highlighting how this conceptual model could launch future research questions.

Reduced adolescent risk-assessment and lower nicotinic beta-2 expression in rats exposed to nicotine through lactation by forcedly drinking dams.

Few animal studies focus on consequences of nicotine postnatal exposure, particularly through lactation. We have recently shown that forced nicotine drinking elevates maternal care, paradoxically provoking arousal and stress in pups. Present work aimed to evaluate the specific contribution of altered maternal cares, compared to the sequelae merely due to nicotine effects. Two groups were compared to water-drinking control dams: (i) free-choice dams (H2O+NIC group) drinking from two bottles, containing either nicotine or water; (ii) forced dams (NIC+NIC group) drinking from two bottles, both containing nicotine. We previously demonstrated that nicotine was indeed transferred to the lactating offspring. Regarding behavioural consequences at adolescence, both H2O+NIC and NIC+NIC rats were slower than controls in discovering a novel over a familiar compartment, whilst only NIC+NIC rats exhibited reduced risk-related avoidance and assessment behaviour. Brain analyses at adulthood suggest that, in prefrontal cortex, nicotine per se reduced serotonin, while the maternal overcare reduced CHRN-B2 gene-expression. As a whole, unescapable nicotine-enhanced maternal care could have an impact on the offspring arousal by acting on prefrontal CHRN-B2 gene-expression. When present results are translated to consequences of non-voluntary exposure in humans, we propose that children receiving altered attentions by a smoking caregiver might undergo a neuro-behavioural development biased towards emotional shyness.

Physical home environment is associated with prefrontal cortical thickness in adolescents.

Biologically embedded experiences alter developmental trajectories in ways that can influence health, learning, and/or behavior. These systematic differences in experiences may contribute to different biological outcomes as individuals grow and develop, including at the neural level. Previous studies of biologically embedded experiences on neurodevelopment have focused on large-scale institutional or economic factors (e.g. socioeconomic status [SES]) and psychosocial factors (e.g. caregiving behavior). Less attention has focused on how the quality of the immediate home settings, such as the physical home environment (PHYS), influences neurodevelopment. Moreover, no study has investigated these effects in adolescents, who undergo significant physical maturation and neurodevelopment that may influence how they respond to their physical environments. The goal of the current study was to examine whether PHYS quality is biologically embedded in the developing adolescent brain as evidenced by cognitive achievement and cortical development in 56 (48% female) healthy adolescents (14-18 years (M = 16.83 years, SD = 1.17). Using in-home assessments of the physical home environment, anatomical brain scans, and indices of academic achievement, we found that adolescents who have more physical problems in the home (e.g. structural hazards, crowding, excessive noise, poorly lit) have thinner prefrontal cortices, which was associated with lower levels of reading achievement, independent of SES and psychosocial factors. By conducting home visits to assess physical characteristics of adolescents' home, we highlight a typically overlooked aspect of the home environment that has relevance for adolescents' cognitive and brain development.

Putting the concept of biological embedding in historical perspective.

This paper describes evidence that led to the concept of biological embedding and research approaches designed to elucidates its mechanisms. Biological embedding occurs when experience gets under the skin and alters human biological and developmental processes; when systematic differences in experience in different social environments in society lead to systematically different biological and developmental states; when these differences are stable and long term; and, finally, when they have the capacity to influence health, well-being, learning, or behavior over the life course. Biological embedding emerged from insights in population health on the unique characteristics of socioeconomic gradients: Ubiquity in poor and postscarcity societies alike; gradient seen regardless of whether socioeconomic status is measured by income, education, or occupation; cutting widely across health, well-being, learning, and behavior outcomes; replicating itself on new conditions entering society; and, often, showing that flatter gradients mean better overall societal outcomes. Most important, the gradient begins the life course as a gradient in developmental health, suggesting that the emergence of a multifaceted resilience/vulnerability early in life is the best place to look for evidence of biological embedding. To understand its character, the metaphor of the "archeology of biological embedding" has been used, wherein the surficial stratum of the "dig" is experience and behavior, the shallow stratum is organ system and cellular function, and the deep stratum is gene function. We are now ready to address the fundamental question of biological embedding: How do early childhood environments work together with genetic variation and epigenetic regulation to generate gradients in health and human development across the life course?

The impact of social disparity on prefrontal function in childhood.

The prefrontal cortex (PFC) develops from birth through late adolescence. This extended developmental trajectory provides many opportunities for experience to shape the structure and function of the PFC. To date, a few studies have reported links between parental socioeconomic status (SES) and prefrontal function in childhood, raising the possibility that aspects of environment associated with SES impact prefrontal function. Considering that behavioral measures of prefrontal function are associated with learning across multiple domains, this is an important area of investigation. In this study, we used fMRI to replicate previous findings, demonstrating an association between parental SES and PFC function during childhood. In addition, we present two hypothetical mechanisms by which SES could come to affect PFC function of this association: language environment and stress reactivity. We measured language use in the home environment and change in salivary cortisol before and after fMRI scanning. Complexity of family language, but not the child's own language use, was associated with both parental SES and PFC activation. Change in salivary cortisol was also associated with both SES and PFC activation. These observed associations emphasize the importance of both enrichment and adversity-reduction interventions in creating good developmental environments for all children.