EXECUTIVE SYSTEM DYSFUNCTION IN THE AGED MONKEY - SPATIAL AND OBJECT REVERSAL-LEARNING

As part of an effort to characterize age-related cognitive changes in executive system function in a nonhuman primate model of human aging, the performance of seven rhesus monkeys, 20 to 28 years of age, was co mpared to that of five young adult monkeys, 6 to 11 years of age, on s patial and object reversal tasks. No differences in performance were f ound between the two groups in the initial learning of either task. On spatial reversals, aged monkeys were impaired relative to young adult s, but there was no difference in overall performance between the grou ps on object reversals. Central to this article, a perseverative tende ncy was noted in the aged group on both spatial and object reversal ta sks. Changes in executive system dysfunction may represent an importan t aspect of age-related cognitive decline.