Effects of anterior basolateral amygdala lesions on taste aversions produced by high and low oral doses of LiCl and lactose in the rat.

Adult male hooded rats (n = 12) with bilateral electrolytic lesions centered on the anterior basolateral amygdala (BLA) were given training using procedures meant to produce two different types of conditioned taste aversions (CTAs) to test whether the disruptive effects of such lesions on this form of learning were dependent upon the dosages of the illness-inducing agents used as unconditioned stimuli (UCSs). The CTAs were produced by either LiCl-induced toxicosis or lactose malabsorption. Comparison with sham-operated control subjects (n = 8) indicated that the disruptive effects of the lesions were inversely related to the dosage level of LiCl but not lactose: whilst the lesions disrupted CTAs produced by a low i.p. dose of LiCl and by a low, but not a high, oral dose of LiCl, they did not alter CTA learning produced by either high or low oral doses of lactose. These results were interpreted as providing further evidence that BLA mediates only certain types of CTA learning.