Trace conditioning in 1-day-old rats

A recent test of 3-hr-old rats indicated surprisingly effective trace conditioning with a 60-s trace interval. The present study tested similar trace conditioning in pups 24-hr-old, in the absence of circumstances that immediately follow birth and might promote cognition. In Experiment 1 pairing an olfactory CS with a gustatory US yielded conditioning despite a 120-s trace. Experiment 2 determined that ambient CS odor remaining in the vicinity of the conditioning surface was not sufficient to result in the olfactory-gustatory association. Experiment 3 applied conditioning procedures more like those previously used for the 3-hr-old infant and more stringent than those applied in Experiment 1. With these procedures the 24-hr-old pups nevertheless acquired the CS-US contingency with a 60-s trace. Perhaps perinatal tolerance for long trace intervals is linked to their substantial experience in dealing with odors and tastes prenatally and postnatally.