ABSTRACT
Feeding experiences were varied in developing rats and the effects upon flavor neophobia and lithium chloride-induced flavor aversions were observed. In Experiment 1, nursing experience of neonate rats was reduced by artificial feeding via intragastric cannula; the rats then were tested with apple juice paired with lithium chloride injection at weaning or maturity. Conditioned aversions were not affected, but neophobia to novel apple juice was attenuated in artificially-reared rats tested at maturity. In Experiment 2, rats received enriched feeding experience after weaning, which consisted of (a) obtaining many complex flavors, a few of which were paired with poisoning, effortlessly in the home cage, or (b) foraging for various foods on an elevated maze. No dramatic effects on neophobia or conditioned taste aversion for saccharin water were apparent. In Experiment 3, rats were given experience after weaning with vanilla-scented water either paired or unpaired with quinine water, and then tested with the odor of almond or that odor compounded with saccharin water for neophobia and lithium-induced aversions. Flavor-experienced rats exhibited more pronounced odor conditioning and more resistance to extinction of the odor aversion after both simple and compound conditioning. In contrast, saccharin taste aversions were relatively unchanged. Apparently, enriched feeding and drinking experience facilitates the utilization of odor more than taste cues.
Subject(s)
Avoidance Learning , Conditioning, Classical , Smell , Taste , Animals , Animals, Newborn , Avoidance Learning/drug effects , Chlorides/poisoning , Conditioning, Classical/drug effects , Cues , Drinking/drug effects , Extinction, Psychological/drug effects , Female , Lithium/poisoning , Lithium Chloride , Male , Rats , Rats, Inbred Strains , Smell/drug effects , Social Environment , Taste/drug effectsABSTRACT
The contribution of nonassociative neophobia and sensitization to the potentiation of odor by taste in rats was tested in three experiments. In Experiment 1, neophobia for almond odor (O), saccharin taste (T), and odor-taste compound (OT) cues was tested before and after noncontingent lithium chloride poisoning and compared with conditioned aversions produced by OT-LiCl temporal pairing. The OT compound potentiated unconditioned neophobia, but there was no evidence of poison-enhanced neophobia, disinhibition of neophobia, or sensitization by noncontingent LiCl; temporal pairing produced aversions for the compound and its elements. In Experiment 2, generalization to a novel odor was tested after O-LiCl or compound OT-LiCl pairing. The potentiated odor aversion did not generalize to the novel odor; it was specific to the odor paired with taste and LiCl. In Experiment 3, potentiation of the odor component by a discriminant or nondiscriminant taste component was tested. Potentiation was evident only when a novel discriminant taste was in compound with odor prior to LiCl poisoning. These studies support an associative "indexing" hypothesis of the potentiation effect in rats.
Subject(s)
Association Learning , Learning , Smell , Taste , Animals , Association Learning/drug effects , Avoidance Learning/drug effects , Chlorides/poisoning , Conditioning, Classical/drug effects , Discrimination Learning/drug effects , Drinking/drug effects , Learning/drug effects , Lithium/poisoning , Lithium Chloride , Male , Odorants , Rats , Rats, Inbred Strains , Smell/drug effects , Taste/drug effectsABSTRACT
Potentiation of odor by taste in rats was tested in a variety of situations. In three experiments, almond odor and saccharin taste were presented either as a single conditioned stimulus (CS) or as a compound CS and followed by either toxic lithium chloride or footshock. Extinction tests with the almond and saccharin components were then given. In single CS-toxin experiments, taste was more effective than odor, and after compound conditioning, the taste component potentiated the odor component. Conversely, in single CS-shock experiments, odor was more effective than taste, and after compound conditioning, no potentiation was observed. Rather, interference effects were observed. In Experiments 1 and 2, the addition of taste disrupted odor CS-shock conditioning, and in Experiment 3, odor interfered with taste CS-shock conditioning. Visceral feedback is apparently a necessary unconditioned stimulus for the potentiation of odor by taste. These data support the neural convergence and gating hypothesis of flavor aversion conditioning.
Subject(s)
Association Learning/drug effects , Avoidance Learning/drug effects , Chlorides/poisoning , Learning/drug effects , Lithium/poisoning , Smell/drug effects , Taste/drug effects , Animals , Conditioning, Classical/drug effects , Cues , Drinking/drug effects , Electroshock , Lithium Chloride , Male , Rats , Rats, Inbred StrainsABSTRACT
When either taste or odor alone was followed by poison, rats acquired a strong aversion for the taste but not for odor, especially if poison was delayed. When odor-taste combinations were poisoned, however, odor aversions were potentiated, as if odor could gain the enduring memorial property of taste by associative contiguity.
