Parental abuse, stress can affect brain development in children, says study
It is not just harmful chemicals that interfere with brain development in children. Abusive parents can, too. A new study involving animals shows that while stress alone can harm the hippocampus [a major component of the brain], when combined with abuse from the mother, it can negatively impact the development of the infant brain and restrict its growth.
The new study performed in rats lays out the consequences of abuse in children. The findings further show that pups' brains also respond to stress and abuse - and together they arrest development in the brain, prompting them to distance themselves from their mothers.
Child neglect can be inadequate health care facilities and deprivation of food. In the US, the most common form of child maltreatment is neglect: about 74.9 percent of children suffer from neglect.
Past research has shown that children born to abusive mothers have impaired amygdala and hippocampus - parts of the brain associated with emotions and memory.
In this study, researchers recreated abusive behavior in rats to study changes in the brain and behavior, an equivalent of which would be to prevent pups from receiving sufficient nesting materials from new rodent mothers.
To tease apart the effects of abusive mothers and the associated stress, they performed two sets of experiments. One set of pups were subjected to rough handlings or abuse for a week. And another group of pups were left unabused but injected with stress-inducing hormones such as corticosteroids: out of which some grew with a nurturing mother while others had an anesthetized mother, or a still object, for company.
Both the groups showed similar behavioral changes: they tended to avoid their mothers, by unnaturally keeping their distance from their mothers. Behavioral changes reflected in the pups' brains too. They found that stress alone damaged the hippocampus. But when this was accompanied by the presence of an abusive mother, the researchers saw limited growth in the amygdala, along with changes in behavior.
But the damage, the researchers say, is reversible. By blocking the effects of corticosteroids and exposing the pups to caring mothers, the researchers say that there is hope.
"Mothers and other close caregivers have special access to the infant brain and consistent abuse, if left to continue, may do lasting damage. But our findings also suggest that mothers or their surrogates have the innate ability to help mitigate the damage through good parenting", according to senior investigator Regina M. Sullivan, PhD, a professor in the Department of Child and Adolescent Psychiatry at NYU Langone Health.
In the future, the researchers plan to expand their study by investigating the specific role of other hormones during stressful situations. The study was published in the Proceedings of the National Academy of Sciences (PNAS).