“…A vast literature clearly illustrates the profound impact of early life experience on emotional temperament and neuroendocrine reactivity (Levine et al, 1957,Levine, 1962,Levine et al, 1967,Zarrow et al, 1972,Hofer, 1973,Russell, 1973,Ladd et al, 2000,Sanchez et al, 2001,Arnold and Siviy, 2002. While we recently showed that the HR-LR trait appears to be heritable (Stead et al, 2006a), we also wanted to ascertain whether early maternal influences could also modulate the phenotype.…”