Recent memory in aged non-human primates: hypersensitivity to visual interference during retention.

The effect of irrelevant visual information presented during retention of recent memory was investigated in young and aged monkeys. The monkeys were required to remember the location of a visual stimulus over short durations, during which time, on certain trials, irrelevant visual stimulation was presented. It was found that although the young monkeys performed as well with or without the irrelevant stimulation, the aged monkeys were significantly impaired when irrelevant stimulation was presented. Thus, these data provide direct support for the notions that aged subjects suffer a decreased ability to suppress visual stimuli from interfering with accurate behavior, and that this disability contributes to the memory impairments reported with old age. When considered with previous research in humans and non-human primates, these results suggest that this disability to suppress sensory interference may reflect a general effect of aging which may contribute to many other age-related behavioral impairments. Finally, it was suggested that the striking similarities of the behavioral profile now established for the aged monkey to that of younger monkeys suffering destruction of the frontal cortex (and anatomically related subcortical sites) offers the heuristic possibility that these two syndromes share a common neurological etiology.