When children have been exposed to family violence, their brains become increasingly "tuned" for processing possible sources of threat, a new study reports. The findings, reported in the December 6th issue of Current Biology, a Cell Press publication, reveal the same pattern of brain activity in these children as seen previously in soldiers exposed to combat.
The study is the first to apply functional brain imaging to explore the impact of physical abuse or domestic violence on the emotional development of children, according to the researchers.
"Enhanced reactivity to a biologically salient threat cue such as anger may represent an adaptive response for these children in the short term, helping keep them out of danger," said Eamon McCrory of University College London. "However, it may also constitute an underlying neurobiological risk factor increasing their vulnerability to later mental health problems, and particularly anxiety."
Maltreatment is known to be one of the most potent environmental risk factors associated with anxiety and depression. Still, McCrory said, "relatively little is known how such adversity 'gets under the skin' and increases a child's later vulnerability, even into adulthood."
The new study shows that children with documented exposure to violence in the home differ in their brain response to angry versus sad faces. When presented with angry faces, children with a history of abuse show heightened activity in the brain's anterior insula and amygdala, regions involved in detecting threat and anticipating pain.
McCrory says the changes don't reflect damage to the brain. Rather, the patterns represent the brain's way of adapting to a challenging or dangerous environment. Still, those shifts may come at the cost of increased vulnerability to later stress.
Although the results may not have immediate practical implications, they are nonetheless critical given that a significant minority of children are exposed to family violence, McCrory says. "This underlines the importance of taking seriously the impact for a child of living in a family characterized by violence. Even if such a child is not showing overt signs of anxiety or depression, these experiences still appear to have a measurable effect at the neural level."