Effects of basolateral amygdala lesions on taste aversions produced by lactose and lithium chloride in the rat.
In Experiment 1, intact rats were given either lactose or sucrose solutions. Although on first exposure they readily consumed lactose, its ingestion produced a conditioned taste avoidance which was partly extinguished by repeated sucrose exposure after lactose conditioning. In Experiment 2, rats with large bilateral electrolytic lesions of the basolateral amygdala and those with either sham or no operations were given two pairings of saline with LiCl injections (upper gastrointestinal tract discomfort) and in a separate condition access to high levels of lactose (lower gastrointestinal tract discomfort). Conditioned taste avoidances were measured both by two-bottle tests and by video recordings of the rats' orofacial and somatic responses. The lesions attenuated LiCl-induced taste aversion but not lactose-induced taste avoidance, results demonstrating that taste avoidance can occur without the basolateral amygdala. The results suggested that aversions based on distaste can be distinguished from avoidances based on danger, not only in terms of orofacial responses but also in terms of their neuroanatomical substrate.
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001245:Association Learning / Q000502:physiology; D001362:Avoidance Learning / Q000502:physiology*; D002712:Chlorides / Q000506:poisoning; D003214:Conditioning, Classical / Q000502:physiology; D004326:Drinking / Q000187:drug effects; D005108:Extinction, Psychological / Q000502:physiology; D007785:Lactose / Q000008:administration & dosage; D008094:Lithium / Q000506:poisoning; D018021:Lithium Chloride; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013649:Taste / Q000502:physiology*
D002712:Chlorides; D008094:Lithium; D018021:Lithium Chloride; D007785:Lactose