Dissociative effects of selective lesions in the caudate nucleus of cats and rats.

Lesions in the neostriatal region connected to the prefrontal cortex severely impaired delayed alternation in both cats and rats, whereas no such effect was found after damage to other neostriatal regions. These results indicate that the processes mediating delayed alternation are well localized in the neostriatum of both cats and rats. Two possible models of neostriatal functioning are discussed, one of functional heterogeneity, the other of functional homogeneity.