THE FLEXIBLE USE OF MULTIPLE-CUE RELATIONSHIPS IN SPATIAL NAVIGATION - A COMPARISON OF WATER MAZE PERFORMANCE FOLLOWING HIPPOCAMPAL, MEDIALSEPTAL, PREFRONTAL CORTEX, OR POSTERIOR PARIETAL CORTEX LESIONS

Rats prepared with lesions of the prefrontal cortex, posterior parieta l cortex, hippocampus, or medial septal area were tested for acquisiti on of a number of variations of the open-field water maze using a vers ion of place learning assessment described by Eichenbaum, Stewart, and Morris (1991). Specifically, the individual role of the aforementione d cortical and subcortical structures in tasks with differing represen tational demands on navigation were assessed. The results suggest that the sham-operated control, posterior parietal cortex-lesioned rats, a nd medial septal area-lesioned rats were able to navigate effectively under changing task conditions. Conversely, the navigational performan ces of the prefrontal cortex-and hippocampal formation-lesioned rats w ere impaired when task demands changed. The results are discussed in t erms of the flexible use of multiple distal cues to guide navigation a nd the resulting loss of this flexibility after lesions to either the prefrontal cortex or the hippocampus. (C) 1997 Academic Press.