IMPAIRED SPATIAL INFORMATION-PROCESSING IN AGED MONKEYS WITH PRESERVED RECOGNITION MEMORY

SPATIAL information processing was examined in a nonhuman primate mode l of cognitive aging, using procedures formally similar to tasks desig ned for rats. The test apparatus was a large open field containing eig ht reward locations. Monkeys rapidly learned to visit each location on ce per trial, and probe manipulations confirmed that young animals nav igated according to the distribution of cues surrounding the maze. In contrast, aged monkeys solved the task using a response sequencing str ategy, independent of extramaze spatial information. Object recognitio n memory was normal in the aged group. The results reveal substantial correspondence in the cognitive effects of aging across rat and primat e models, and they establish appropriate procedures for testing the lo ng-standing proposal that the role of the hippocampus in normal spatia l learning is similarly conserved.