Taste reactivity in rats following lesions of the zona incerta or amygdala

Abstract

Rats with amygdala lesions (n=12) and rats with zona incerta lesions (n=12) were compared to normal rats (n=12) in their response to various taste stimuli. Five concentrations each of sucrose, sodium chloride, quinine hydrochooride, and hydrochloric acid were presented to all animals in single bottle tests during a schedule of restricted fluid access. Results indicated that both groups of rats with lesions had significantly lower baseline water consumption than normal rats. Using taste consumption measures expressed as a percent of water baseline, it was found that zona incerta lesions did not significantly alter normal taste reactivity. Animals with zona incerta lesions did fail to show normal habituation to a 0.0001 M quinine solution over repeated presentations. Lesions of the amygdala resulted in an increase in consumption of the acid solutions; consumption of sucrose, quinine, and sodium chloride was normal across concentrations. Amygdala damaged rats failed to show normal neophobia when first presented with the 0.0001 M quinine solution. It was concluded that taste response functions of rats with lesions of the zona incerta or amygdala remain essentially normal following surgery but that subtle changes in reactivity do occur, particularly with regard to neophobia.