| Summary: | The experiments reported in the present dissertation investigated the contribution of the pyriform cortex and of the basolateral amygdala to three classes of affective behavior: conditioned aversions, conditioned preferences, and neophobia. It was demonstrated that lesions of the pyriform cortex cause an impairment in the acquisition of aversions to olfactory, but not gustatory, stimuli and that this impairment is not secondary to alterations in primary olfactory function. The acquisition of a preference for a particular odor paired with reward was also shown to be impaired by such lesions. These results are discussed in terms of the rich innervation of the pyriform cortex by olfactory fibers, and of its projections to sub-cortical structures. Ibotenic-acid lesions of the basolateral amygdala caused a significant deficit in conditioned taste aversion, whereas these same lesions did not affect conditioned odor aversion. This dissociation was examined in light of the differences in anatomical projections from the olfactory and gustatory cortical areas to the basolateral region. The performance of animals with electrolytic lesions of the basolateral amygdala on a conditioned taste- and a conditioned odor-preference task raised some important questions concerning the contribution of this neural structure to stimulus-reward associations. The last two experiments demonstrated that the pyriform cortex plays an important role in neophobia, a role that is not limited to olfactory stimuli. This suggests that the analysis and subsequent transmission of olfactory information is critical to the expression of the neophobic response.
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