BEHAVIORAL AND PHYSIOLOGICAL CONSEQUENCES OF SUCKLING IN RAT AND HUMAN NEWBORNS

Suckling, in addition to yielding milk, water and calories, exerts pro found behavioral effects on newborn rats and humans. In particular, su ckling induces feelings of calm, reduces heart rate and metabolic rate , causes infants to bring their hands to their mouths and elevates the pain threshold. These changes are mediated by opioid and non-opioid s ystems, each having its own separate behavioral and neurological chara cteristics. The implications of suckling-induced changes for longterm motivational and cognitive change are discussed.