Age-related impairments in spatial memory are independent of those in sensorimotor skills

Seventy-five aged rats were tested for a variety of motor and cognitive tests which generated 20 separate measures of performance. Considerable variability was observed on many measures in the aged population. Multivariate analyses were performed on the data to determine 1) the extent of intercorrelations between the measures for the aged rats, and 2) whether clusters of related and/or unrelated behavioral measures could be determined. Aged rats that were impaired on measures of cognitive performance are not necessarily impaired in their motor performance and vice versa. These results demonstrate that different age-related variables affect cognitive and motor systems, and suggest that age-related declines in different functional anatomical systems, such as the limbic system and the basal ganglia may progress independently.