Thalamocortical relations in taste aversion learning: II. Involvement of the medial ventrobasal thalamic complex in taste aversion learning.

Examined the involvement of the gustatory thalamic nuclei in fundamental taste reactivity, gastrointestinal reactivity, and conditioned taste aversion (CTA) learning. In Exp I, using 72 male Long-Evans rats, bilateral electrolytic lesions were produced in the medial ventrobasal thalamic complex (VBm), including the thalamic gustatory nuclei, in 1 group of Ss. For a 2nd group, at the conclusion of conditioning, lesions were produced in the anterior insular gustatory neocortex (AIGN). Results indicate that destruction of VBm thalamus attenuated taste reactivity to sucrose, citric acid, and quinine hydrochloride. Elimination of VBm thalamus markedly attenuated CTA learning. Results of neocortical lesion manipulations showed that the AIGN contributed to initial CTA learning in Ss lacking a mediodorsal-periventricular thalamus. Whether Ss lacking VBm thalamus used olfactory cues associated with drinking solutions to acquire CTAs was evaluated in Exp II, using 72 male Long-Evans rats. Results demonstrate that Ss lacking VBm thalamus and the olfactory bulbs could not acquire aversions to ingested LiCl following 8 conditioning trials. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)