The sobering application of the finding of this 2013 rodent study was that if the limbic systems of human children weren’t already permanently damaged before they entered an orphanage, the orphanage experience would probably do that to them:
“The current study manipulates the type and timing of a stressor and the specific task and age of testing to parallel early-life stress in humans reared in orphanages.
The results provide evidence of both early and persistent alterations in amygdala circuitry and function following early-life stress.
These effects are not reversed when the stressor is removed nor diminished with the development of prefrontal regulation regions.”
http://www.pnas.org/content/110/45/18274.full “Early-life stress has persistent effects on amygdala function and development in mice and humans”