We have known since the 1950s that the quality of care infants receive from parents has enduring effects on brain circuits controlling emotion and cognition, as well as ubiquitous changes in gene regulation, epigenetics, myriad neurotransmitters/hormone, and brain anatomy throughout the brain. However, mechanisms by which experiences initiate different developmental pathways remain incompletely understood. Here we focus on one variable during mother-infant interactions: how well the mother buffers (attenuates) the offspring’s stress response and aberrant infant behavior. Using a rodent animal model, we have begun to question the neurobiology of social buffering within attachment during typical rearing, as well as within trauma associated interactions with the parent (maltreatment). First, within typical attachment, we present data illustrating how mothers’ social buffering of pups’ stress response can alter the offspring’s amygdala and its network to alter learning about trauma. Next, we present data showing how maltreatment by the mother blunts this neural network processing. Finally, we present within nest neurobehavioral data for ecological significance suggesting the mother is engaged in moment-to-moment regulation of pups’ cortical and amygdala oscillations, which is also disrupted in pups maltreated by the mother. For all examples, maternal regulation of the offspring’s brain decreases as pup approaches independence and is disrupted by adversity (maltreatment).