SIMULTANEOUS OVERSHADOWING AND POTENTIATION OF TASTE AND CONTEXTUAL CUES BY A 2ND TASTE IN TOXICOSIS CONDITIONING

Three experiments examined the effect of sucrose consumption in a nove l context on the conditioning of an aversion to that context. In Exper iment 1, rats were injected with LiCl after drinking either sucrose (G roup SUC-LI) or water (Group WAT-LI) in a novel context (context 2). A n unpoisoned control group consumed water in context 2 and was injecte d with isotonic saline solution (Group WAT-SAL). On test, when present ed with saline in context 2, Group WAT-LI consumed less than Group WAT -SAL, suggesting that a conditioned aversion to context 2 developed in Group WAT-LI. Group SUC-LI consumed less than Group WAT-LI, suggestin g that the sucrose had potentiated a context aversion in Group SUC-LI. Experiment 2 was similar ro Experiment 1, except that rats drank a no vel vinegar solution in context 1 before entering context 2 for condit ioning. On rest, Group SUC-LI drank more vinegar in context 1, and les s saline in context 2, than Group WAT-LI, suggesting that sucrose had simultaneously overshadowed vinegar and potentiated an aversion to con text 2. Experiments 3a and 3b confirmed that the results of Experiment 2 were due to potentiation rather than generalization of a sucrose av ersion to familiar saline. (C) 1996 Academic Press, Inc.