EFFECTS OF PARIETAL CORTEX LESIONS ON SPATIAL PROBLEM-SOLVING IN THE RAT

The Maier 3-table task was used to examine spatial representations in rats with lesions of the parietal cortex. Some animals had anteriorly placed lesions, some posteriorly placed in cortical areas, sometimes r egarded as 'parietal' in earlier studies. After 5 days of familiarizat ion, animals were given 18 days of testing on the standard Maier task. Both parietal groups were initially impaired, but reached the same le vel of performance as controls by the end of the test period. Learning occurred both within and between sessions for the anterior group, but only between sessions for the posterior group. There was no major fun ctional differentiation apparent on this task between the two 'parieta l' areas. Rate of exploration increased in both parietal groups across test sessions as task performance improved. It is argued that the cha nge in exploratory activity across sessions in parietal groups may ref lect the adoption of a compensatory strategy which improved performanc e, but that improvement could also have been due to neural changes, as structures, such as the frontal cortex or hippocampus, assume some fu nctions normally mediated by the parietal area.