THE EFFECTS OF DORSAL VERSUS VENTRAL HIPPOCAMPAL, TOTAL HIPPOCAMPAL, AND PARIETAL CORTEX LESIONS ON MEMORY FOR ALLOCENTRIC DISTANCE IN RATS

To test for the contribution of the parietal cortex and hippocampus to memory for allocentric spatial cues, the authors trained rats on a go /no-go task that required the rat to remember the distance between two visual cues. Total hippocampal lesions impaired working-memory repres entation for allocentric distance, whereas parietal cortex lesions res ulted in only a transient impairment. In a second experiment, neither hippocampal nor parietal cortex lesions impaired allocentric distance discrimination. A third experiment showed that both the dorsal and ven tral areas of the hippocampal formation must be destroyed to impair wo rking memory for allocentric distance information. There appears to be a dissociation between the hippocampus and parietal cortex in mediati ng memory for allocentric distance information.