Disturbances of Neophobia and Taste-Aversion Learning After Bilateral Kainate Microlesions in the Rat Pallidum

These experiments aimed to elucidate feeding-associated behavioral roles of globus pallidus (GP) neurons in gustatory functions: The effects of bilateral microiontophoretic kainate (KA) lesions of the ventromedial pallidal (vmGP) region on neophobia and conditioned taste aversion (CTA) were studied. Lesioned rats displayed strong and persistent neophobia to a mild citric acid solution. Neuron-specific damage to the vmGP also prevented rats from proper acquisition of CTA. Rats that previously showed normal neophobia and successfully learned CTA demonstrated difficulties in CTA retention after GP lesions. KA-lesioned rats, in addition, exhibited deficits in orientation reactions but did not have aphagia, adipsia, or motor disturbances seen after larger pallidal lesions. These findings suggest that neurons of the GP are significant in acquisition, memory storage, and retrieval mechanisms of feeding-associated taste information.