Living in dangerous and violent neighbourhoods can affect children’s brain development

Living in neighbourhoods with high levels of violence can affect children’s brain development by altering the parts of the brain that detects and responds to potential threats, potentially leading to poorer mental health and other negative outcomes, a new study has shown. 

Despite the challenges of growing up in such a context researchers also found that the presence of nurturing parents can provide some level of protection to the detrimental effects. 

“Decades of research has shown that growing up in neighborhoods with concentrated disadvantage can predict negative academic, behavioural and mental health outcomes in children and teens,” Dr Luke W. Hyde, a coauthor of the study said. 

“Recent research is beginning to show that one way it does that is by impacting the developing brain ,however, less is known about how neighborhood disadvantage ‘gets under the skin’ to impact brain development.”

Dr Hyde and his colleagues hypothesized that one way might be through the amygdala, the hub of the brain’s stress response system that’s involved in socioemotional functioning, threat processing and fear learning. 

The amygdala is sensitive to facial expressions, and previous research has found that children who have been abused or neglected by family members, for example, show increased reactivity in the amygdala when looking at faces with negative, fearful or neutral expressions.

To reach their findings the researchers analysed data from 708 children and teens ages 7 to 19 years, recruited from 354 families enrolled in the Michigan Twins Neurogenetic Study. 

Most sets of twins were from neighbourhoods with above-average levels of poverty and disadvantage, as measured by the U.S. Census Bureau. Fifty-four percent of the participants were boys, 78.5 per cent were white, 13 per cent were Black and 8 per cent were other races and ethnicities. The participants lived in a mix of rural, suburban and urban areas in and around Lansing, Michigan.

Teens completed a set of surveys that asked about their exposure to community violence, their relationship with their parents and their parents’ parenting style. Participants also had their brains scanned by functional MRI while they looked at faces that were angry, fearful, happy or neutral.

Overall, the researchers found that participants who lived in more disadvantaged neighborhoods reported more exposure to community violence. Participants who reported more exposure to community violence showed higher levels of amygdala reactivity to fearful and angry faces. The results held true even when controlling for an individual family’s income, parental education and other forms of violence exposure in the home, such as harsh parenting and intimate partner violence.

“This makes sense as it’s adaptive for adolescents to be more in tune to threats when living in a more dangerous neighborhood,” Dr Hyde said.

However, he and his colleagues also found that nurturing parents seemed to be able to break the link between community violence and amygdala reactivity in two ways.

“Despite living in a disadvantaged neighbourhood, children with more nurturing and involved parents were not as likely to be exposed to community violence, and for those who were exposed, having a more nurturing parent diminished the impact of violence exposure on the brain,” fellow researcher Gabriela L. Suarez said. 

“These findings really highlight how nurturing and involved parents are helping to support their children’s success, even in potentially harsh environments, and offer clues as to why some youth are resilient even when facing adversity.”

Access “Exposure to Community Violence as a Mechanism Linking Neighborhood Disadvantage to Amygdala Reactivity and the Protective Role of Parental Nurturance,” here.