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Although cognitive decline has been well established as a consequence of aging in non-human primate models, the prevalence or frequency of impairment for specific age ranges has not been described. The first aim of this study was to estimate prevalence of cognitive impairment on each of the six tests of cognitive performance by comparing the performance of(More)
This study investigated the effects of different rearing conditions on neural and cognitive development of male rhesus monkeys (Macaca mulatta). Infants raised individually in a nursery from 2 to 12 months of age (NURSERY, n=9) were compared to age-matched infants raised in a semi-naturalistic, social environment (CONTROL, n=11). Various brain regions were(More)
Assessment of recognition memory was performed on eight rhesus monkeys of advanced age (25 to 27 years of age) using the delayed recognition span test (DRST). Their performance was compared to that of five young adult animals (5 to 7 years of age) on two stimulus conditions of the DRST: spatial position and color. Both trial unique and repeating series were(More)
Studies on human postmortem material report lower brain weights in older than in younger cohorts, whereas there is no apparent change with age in the rhesus monkey. In view of these contrasting results, we examined the pattern of brain weight across the life span in the chimpanzee, one of the closest biological relatives of humans. To place the study in(More)
The Simian immunodeficiency virus (SIV) infected macaque model exhibits neuropathological symptoms similar to those of HIV(+) patients, and is ideal for studying cognitive impairment and neuropathological sequelae of disease in repeated measurements. The aim of this study is to use Diffusion Tensor Imaging (DTI) and perfusion MRI to longitudinally access(More)
The "frontal aging hypothesis" has been proposed by many researchers suggesting that the earliest and most severe age-related changes in the cortex occur in the frontal lobes. Two of these changes include decreases in cognitive functions mediated by the prefrontal cortex (PFC) and significant decreases in norepinephrine (NE) and dopamine (DA). To(More)
Understanding the nature of changes in cognition with aging has increased in importance as the number of individuals over the age of 65 years grows. To date, studies have demonstrated that age-related changes occur most extensively in the cognitive domains of memory and executive function. Whereas a large number of studies have been conducted about the(More)
As our understanding of age-related cognitive decline advances, studies are now focusing on identification of those areas of cognitive function that undergo the first changes with age. In the present study, in order to determine whether executive function is sensitive to the aging process, we assessed the performance of 16 monkeys of middle-age (12-19 years(More)
Estrogen deficiency following ovariectomy or menopause increases the risk of developing diseases such as osteoporosis and may also lead to memory impairment. Although estrogen replacement therapy (ERT) alleviates many symptoms associated with estrogen loss, it is not clear whether it also benefits cognitive function. The effect of estrogens upon cognition(More)
The nigrostriatal system is critical for fine motor function and its deterioration during aging is thought to underlie the decline in fine manual ability of old persons. Because estrogen has a neuroprotective effect on this system, one might expect women's motor function to be less vulnerable to the detrimental effects of aging than that of men. We examined(More)