In the late 1950s and early 1960s the pages of Science and Nature were frequently dedicated to articles reporting the effects of postnatal handling on the development of responses to stressors.35-37 The handling paradigm involves a brief (ie, ~15 min) separation of the pups from the dam that does not constitute any major deprivation of parental care. In infant rats and mice, handling during infancy decreases the magnitude of both behavioral and HPA responses to stress in adulthood. These findings demonstrated that the early environment influences the development of even rudimentary defensive responses to threat.
