The title of this post may seem a bit strange for some and obvious for others, but I do think it’s an interesting extra dimension to something we’ve known for quite a while now: (toxic) stress at a young age can have a huge effect on the development of the brain, and therefore it’s not surprising to me that also the neighborhood can have a negative effect too. A good thing about this study is that they have used a really big sample, which is not often the case in this kind of study. Still, it’s quite a depressing read with some hope at the end.

From the press release:

 Many socioeconomically disadvantaged children face poor cognitive and mental health outcomes, and researchers are working to determine the specific factors that link childhood conditions to those poor outcomes, including how they might shape brain circuitry. In a new study, researchers have examined how “neighborhood disadvantage” can affect the developing brain, including the brain’s connectivity between regions.

The study appears in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier.

Sarah Whittle, PhD, and Divyangana Rakesh, lead authors of the study, studied existing brain scans from 7,618 children aged 9-10 collected as part of the Adolescent Brain Cognitive Development (ABCD) Study. Previous studies have identified differences in some brain regions in disadvantaged children, but the current study used magnetic resonance imaging (MRI) to measure functional connectivity, or how well different regions of the brain are connected with one another, at rest.

Rather than considering a single measure of status such as household income, the new study classified children according to neighborhood disadvantage, which encompasses multiple risk factors such as pollution, crime, and access to lower-quality education and healthcare.

Dr. Whittle said the purpose of the study was to “inform us of the mechanisms through which disadvantage impacts children’s development and functioning.” The team also wanted to investigate the role of factors such as positive home and school environments that may help reduce the harmful effects of disadvantage.

Analysis of the brain scans revealed that, in children with higher scores reflecting greater disadvantage, functional connectivity was reduced both between and within several brain networks.

“Our findings suggest that growing up in a disadvantaged neighborhood indeed impacts the brain. Importantly, however, findings suggest that providing children with better home and school environments where they feel supported, receive positive feedback, and have opportunities to engage in different activities, can offset some of the negative effects of neighborhood disadvantage on children’s brain development,” Ms. Rakesh said.

The findings have policy implications in the context of designing interventions and policies targeted at youth and families exposed to disadvantage; they suggest a need to shift attention from a sole focus on family-level factors to community-level research and policies.

Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the study, “These remarkable results show that improvements in the home and school environments can mitigate against the otherwise deleterious effects of growing up in a disadvantaged setting, providing a powerful message for the importance of public policies that provide more support at home and at school.”

Abstract of the study:

Objective
Neighborhood disadvantage has consistently been associated with mental health and cognitive function, in addition to alterations in brain function and connectivity. However, positive environmental influences may buffer these effects. The aim of the present study was to examine the association between neighborhood disadvantage and resting-state functional connectivity (rsFC), the moderating role of positive parenting and school environment, and relationships between disadvantage-associated rsFC patterns and mental health and cognition.

Methods
In this pre-registered study, we tested this hypothesis in a large sample of 7618 children (aged 9-10 years) from the Adolescent Brain Cognitive Development (ABCD) Study. Specifically, we analyzed the relationship between neighborhood disadvantage and system-level FC. We also tested whether positive family and school environmental factors, and sex, moderated effects. Finally, we investigated multivariate relationships between disadvantage-associated rsFC patterns and cognition and mental health.

Results
Disadvantage was associated with widespread alterations in FC across both higher-order (e.g., default mode network and dorsal attention network) and sensorimotor functional systems; some of which were moderated by positive environments. Implicated connections showed multivariate associations with behavior, whereby disadvantage-associated rsFC was generally associated with worse cognition and mental health. Disadvantage-associated connections also predicted variation in cognitive scores using machine learning models.

Conclusions
Our findings shed light on potential mechanisms (i.e., alteration of neural circuitry) through which neighborhood disadvantage may affect youth cognition and mental wellbeing. This work highlights the importance of positive family and school environments in mitigating some of these effects.