Effects of excitotoxic lesions of the gustatory thalamus on latent inhibition and blocking of conditioned taste aversion in rats.

The influence of bilateral excitotoxic lesions of the gustatory thalamus on latent inhibition and blocking of conditioned taste aversion (CTA) was examined in two experiments. In Experiment 1, rats with thalamic lesions showed normal latent inhibition by acquiring a CTA that was significantly weaker when the conditioned stimulus (CS) was familiar than when it was novel. In Experiment 2, the preconditioned element (sodium chloride) of a compound CS blocked the acquisition of a CTA to the novel element (sucrose) in normal rats. Irrespective of whether sodium chloride was preconditioned or not, rats with thalamic lesions showed little or no aversion to sucrose following compound conditioning. Overall, the results provide no support for the experimental hypothesis that thalamic lesions disrupt decremental changes in the attentional processing of gustatory stimuli.