Mimetic behavior of rats in flavor aversion learning

Rats exposed to odor (almond), taste (saccharin) or an odor/taste-compound (almond/ saccharin) in a one-trial conditioning were subsequently poisoned with lithium chloride either 5 min (Ex) or 16 h (Co) after drinking. We measured various behavioral CRs elicited by these conditioned stimuli. All stimuli and compounds produced strong flavor aversions and elicited a pattern of agitated behavior characterized by increased general activity, rearing, and the specific mimetic response 'gaping' in the experimental groups. No comparable patterns were observed in the control groups. In the compound-experimental group an overshadowing effect for the odor component by the new taste was found. However, odor in this condition still elicited somewhat reduced drinking and the typical aversive reaction pattern. Behaviors induced by pairing odor with illness were more strongly controlled by the presence of the poisoned odor in the compound condition than in the odor condition. The compound experimental group discriminated more strongly, in general, behaviors and in their mimetic responses between the time when odor was presented or not in a test procedure, which alternated poisoned odor and air.