EFFECTS OF LESIONS TO AMYGDALA, VENTRAL SUBICULUM, MEDIAL PREFRONTAL CORTEX, AND NUCLEUS-ACCUMBENS ON THE REACTION TO NOVELTY - IMPLICATIONFOR LIMBIC-STRIATAL INTERACTIONS

The effects of bilateral excitotoxic lesions of 3 major sources of aff erents to the ventral striatum (nucleus accumbens) were compared on an open field test of food neophobia allowing the choice between familia r and novel food. Whereas lesions of the basolateral amygdala and vent ral subiculum had qualitatively similar effects to reduce food neophob ia (although not affecting the latency to eat), amygdala lesions incre ased and the ventral subiculum decreased locomotor activity. In contra st, damage to the ventromedial prelimbic prefrontal cortex only affect ed initial food choice and latency measures. By comparison, excitotoxi c lesions of the nucleus accumbens itself and intra-accumbens infusion of the N-methyl-D-aspartate (NMDA) receptor antagonist AP5 increased activity and attenuated food neophobia. Results are discussed in terms of the role of limbic and prefrontal neuronal networks converging in the nucleus accumbens to control different aspects of the behavioral r esponse to novelty.