Growing up in a disadvantaged neighborhood can change kids’ brains – and their reactions

PTI, Jun 21, 2022, 11:57 AM IST

Perth: Understanding the facial expressions of others is an important development stage. It helps us learn non-verbal communication and to recognize when someone is angry or scared and primes us to react to threats or show empathy for others’ feelings. A growing body of evidence suggests our neighborhood environment shapes this response in children’s brains in different ways, depending on the dynamics of the neighborhood itself.

The amygdala is an important brain structure for recognizing and reacting to facial expressions. It is responsible for our “fight or flight” response and is sensitive to emotional facial expressions, especially those related to threats.

While this primitive alert system is useful to keep us safe, the amygdala can’t differentiate between real threats and emotions like stress, aggression, anger, or fear. This means we often have the same “fight or flight” response to different situations.

A recent study examined the link between neighborhood disadvantage and amygdala reactivity to emotional faces in kids. The researchers wanted to understand whether positive or negative social aspects of the neighborhood could influence amygdala reactivity in childhood.

Making connections The amygdala is particularly responsive to our environment, especially as children when our brains are developing.

Kids exposed to extreme trauma growing up – such as living in a warzone or experiencing physical or emotional abuse – show altered brain pathways for fear and anger processing, with new brain connections allowing faster and more intense emotional responses. This means that kids may be more “on guard” and quick to react to negative emotions.

People who grow up in disadvantaged neighborhoods may have an enlarged amygdala, which is related to increased fearfulness. They are more likely to show heightened sensitivity to emotional stimuli. Neighborhood disadvantage and amygdala reactivity are also linked to antisocial child and youth behaviors.

What is less known is how the environment and social processes of neighborhoods can shape the developing brain, for better or worse. Positive social processes of neighborhoods might include shared beliefs about what behavior is appropriate, community support and trust, and the willingness of neighbors to intervene for the common good.

To understand how neighborhood environments could influence brains, researchers examined 700 children from different neighborhoods in Michigan, United States. To get accurate information about neighborhoods, they used census information to rate neighborhood disadvantages based on employment rates, education, home ownership, and income.

Researchers then used birth records to locate families with twins. Twins are helpful for this kind of research because they live in the same environment so should have the same brain responses. The study included twin families living above and below the poverty line to specifically examine the effects of disadvantaged neighborhoods.

Twins underwent task-based Magnetic Resonance Imaging (MRI) scans. They were shown faces for two seconds and matched faces based on whether they were angry, fearful, happy, or neutral (no expression). The MRI scans detected reactivity of the amygdala in their scans in real-time when viewing the faces.

The study also included adults from the same neighborhoods as the twins. These adult neighbors provided an independent rating of the neighborhood. There were about four neighbors in each twin family.

Neighbors filled out questionnaires about social processes such as community support (e.g. how willing people are to help their neighbors); informal social order (e.g. what someone in the neighborhood might do if a child was left home alone at night); and behavioral norms (e.g. how people in the neighborhood might intervene if a child was doing something dangerous, even if it was not their child).

Neighborhood disadvantage, over-active brains The study found experiences of neighborhood disadvantage resulted in over-activity of the right amygdala, with kids from these neighborhoods being more reactive to facial expressions of anger and fear.

Likewise, if neighbors scored the neighborhood social processes low and thought neighbors did not look out for one another, kids from these neighborhoods were more likely to have a highly reactive amygdala response to emotional faces.

However, researchers also found positive neighborhood social processes could mediate, or lessen, the relationship between neighborhood disadvantage and amygdala reactivity.

When neighbors said the neighborhood worked together cooperatively and was supportive – there was no effect of neighborhood adversity on amygdala reactivity. The kids from these neighborhoods had the same response to expressions of anger and fear as kids from less disadvantaged neighborhoods.

Social connections matter

Neighbourhood environments and social connections are critically important for shaping emotional recognition in kids’ brains. This influence can be positive or negative, depending on the social dynamics of the neighborhood.

This fresh research shows no matter how disadvantaged a neighborhood is, the actions, attitudes, and behavior of the people who live there are highly important influences on how growing children understand and process threats around them.

Growing up in a positive and connected neighborhood where people look out for one another and act in the best interests of the community is one of the best things we can do to give our kids a stable start in life.

(By Sarah Hellewell, Research Fellow, Faculty of Health Sciences, Curtin University, and The Perron Institute for Neurological and Translational Science, Curtin University. The Conversation)