“…However, because of both fetal and post-natal dependence of the offspring on the mother, care must be taken that certain pre-and post-natal maternal variables are not acting indirectly to alter development which becomes manifest as behavioral and/or biochemical changes after birth (Joffe, 1969;Rutledge, 1974). For example, earlier attempts in this laboratory to alter sleep in newborn rats by instrumental (Bobillier, Sakai, Seguin, & Jouvet, 1974) or pharmacological (Carlier, Nowaczyk, Valatx, & Juvancz, 1974) means encountered numerous problems centering on maternal separation.…”