Past studies in animals and humans have established how a mother’s abuse can lead to brain shrinkage in her infants’ amygdala and hippocampus, parts of the brain that process fear and memory, researchers say. The new study, led by researchers from NYU School of Medicine, goes even further, say its authors, to pull apart the effects of abusive parenting from the related stress that follows it. Together, both can negatively impact the growth and development of the infant brain, researchers say.
The study shows how the stress from abuse was sufficient on its own to damage the hippocampus, while the pairing of stress with the presence of an abusive mother was required to restrict growth of the amygdala and to prompt her pups to unnaturally keep their distance and limit their time spent together.
abused infants were hesitant to stay with the mother and nurse, and did so for shorter periods of time whether their mother was awake or not. These effects were replicated when researchers injected unabused, normal pups with the stress hormone corticosterone. Moreover, the negative impact from abuse could largely be blunted by chemically blocking corticosterone action in the infant brain and by exposing stressed pups to nonabusive mothers.
Mothers and other close caregivers have special access to the infant brain and consistent abuse, if left to continue, may do lasting damage. But mothers or their surrogates have the innate ability to help mitigate the damage through good parenting.
Study researchers caution that their research results need not worry caregivers who have caused stress in their baby a few times. it takes more than a few isolated instances of stress to cause long-lasting damage to a child’s brain. Some level of stress hormones, are needed for healthy brain growth and development.
— source nyulangone.org | Oct 21, 2019