Odor-aversion learning in neonate rat pups: the role of duration of exposure to an odor.
Five experiments employed 2- and 10-day-old rat pups to examine the ontogeny of odor-aversion learning. When duration of exposure to the to-be-conditioned odor stimulus (CS) was long, Experiments 1 and 2 demonstrated substantial and similar aversions across the two ages regardless of whether the toxin unconditioned stimulus (US) occurred simultaneously with, immediately before, immediately after, or some time after the CS. These experiments, therefore, did not support the claim of Rudy and Cheatle (Ontogeny of Learning and Memory. Hillsdale, N.J.: Erlbaum (1979) ) that the 2-day old pup suffers a deficit in its learning about the relation between successively presented events. The remaining experiments showed, however, that the 2-day-old pups did not acquire an aversion to a briefly presented CS, that the failure to condition this CS was not due to its overshadowing by contextual cues, and that the 10-day-old pup did acquire an aversion to that CS. The experiments have revealed, therefore, that there are age-related differences in the rat pup's ability to learn about the relation between a briefly-presented CS and the effects of a US.
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001362:Avoidance Learning / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology; D005260:Female; D008297:Male; D009812:Odorants; D051381:Rats; D011919:Rats, Inbred Strains