Olfactory aversive conditioning in the newborn (3-hr-old) rat impairs later suckling for water and milk

J Exp Psychol Anim Behav Process. 2002 Jul;28(3):277-83.


An olfactory conditioning paradigm tested whether newborn rats can acquire a conditioned aversion to olfactory events associated with their first postnatal meal 3-5 hr after birth. Exposure to lemon odor (conditioned stimulus [CS]) paired with intraoral infusions of 0.1% quinine (unconditioned stimulus) resulted in explicit conditioning. Responsiveness to a surrogate nipple providing water in the presence of the CS was significantly lower than the 3 control conditions. The conditioning dramatically suppressed responsiveness to a surrogate nipple providing milk, which normally is expressed voraciously in terms of sustained nipple attachment and milk intake. These findings suggest that as early as 3-5 hr after birth newborn rats are capable of aversive conditioning to odors in the context of suckling behavior.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Newborn
  • Conditioning, Psychological / physiology*
  • Female
  • Male
  • Milk*
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Smell / physiology*
  • Sucking Behavior / physiology*
  • Water*


  • Water