Resilience Might Be Neurobiological

A new study by IPR faculty explores why a second-hand experience with neighborhood violence affects some youth but not others

 chicago crime scene
Why does second-hand experience of neighborhood violence affect some youth but not others?

Neighborhood violence has been associated with adverse health effects on youth, including sleep loss, asthma and metabolic syndrome. Yet some youth living in high-crime neighborhoods manage to avoid these effects.

A new Northwestern University study published in the Proceedings of the National Academy of Sciences (PNAS) aims to answer a resilience puzzle: Why does a second-hand or indirect experience of neighborhood violence affect some youth but not others?

“Little is known about the brain networks that are involved in shaping these different outcomes, a problem we pursue here,” said IPR health psychologist Gregory Miller, lead author of the study. IPR health psychologist Edith Chen and IPR psychologist Robin Nusslock also co-authored the study, in addition to others.

“Like previous studies, we find that youth living in neighborhoods with high levels of violence have worse cardiometabolic health than peers from safer communities,” Miller said. “Extending this knowledge, we show this connection is absent for youth who display higher connectivity within the brain’s frontoparietal central executive network (CEN), which facilitates efforts of self-control as well as reinterpretation of threatening events and suppression of unwanted emotional imagery.”

Drawing on knowledge of the brain’s intrinsic functional architecture, the researchers predicted that individual differences in resting-state connectivity would help explain variability in the strength of the association between neighborhood violence and cardiometabolic health. 

The researchers tested 218 eighth graders from the Chicago area for factors related to metabolic health, including obesity and insulin resistance. Assessing neighborhood factors, including murder rates, the researchers also conducted functional MRI (fMRI) scans of the brains of the study participants.

Consistent with predictions, resting-state connectivity within the central executive network emerged as a moderator of adaptation. Across six distinct outcomes, a higher neighborhood murder rate was associated with greater cardiometabolic risk, but this relationship was apparent only among youth who displayed lower CEN resting-state connectivity. 

No such correlation was apparent, however, in youth that displayed high-resting functional connectivity in the same brain network. According to the researchers, the results suggest a role for the central executive network in adaptability and resilience to adverse events.

The study, due to its design (cross-sectional and observational), cannot claim a causal link between neighborhood violence and health, and the authors conclude that a longitudinal, multiwave study is needed to track neighborhood conditions, brain development and cardiometabolic risk across childhood to establish causality. 

“For basic scientists, these findings provide clues about the neural circuitries that facilitate or undermine adaptation,” Miller said.

Further study could lead to possible interventions, which their preliminary evidence suggests could be “network training” programs to modulate the functional connectivity of the brain’s CEN network. These network training programs can enhance “self-control, threat reappraisal and thought suppression” to lower at-risk teens’ engagement in drug use, overeating, and other reactions to such stress.

Greg Miller is Louis W. Menk Professor of Psychology and an IPR fellow. Edith Chen is John D. and Catherine T. MacArthur Chair and Professor of Psychology and an IPR fellow. Robin Nusslock is Associate Professor of Psychology and an IPR fellow.

This article was originally written by Hilary Hurd Anyaso and published by Northwestern Now.