POSTERIOR PARIETAL CORTEX LESIONS SEVERELY DISRUPT SPATIAL-LEARNING IN DBA MICE CHARACTERIZED BY A GENETIC HIPPOCAMPAL DYSFUNCTION

C57BL/6 (C57) and DBA/2 (DBA) inbred mice with posterior parietal cort ex or sham lesions were tested in a radial eight-arm maze task with al l the paths baited. In the high learner C57 strain, parietal lesions p roduced a limited impairment of performance without affecting maze-run ning strategies while the same lesions were found to affect more sever ely performance in the poor learner DBA strain. Because (1) the proces sing of spatial information has been found to depend on the conjunctiv e participation of the hippocampus and the posterior parietal cortex, and (2) DBA mice represent a genetic model of hippocampal dysfunction, the fact that parietal lesions impair spatial performance more severe ly in the DBA strain suggests that the contribution of the posterior p arietal cortex to spatial learning depends on the degree of functional ity of the hippocampus. (C) 1998 Elsevier Science B.V. All rights rese rved.