Relationship of age-related decline across several behavioral domains.

These studies were designed to assess whether aged rats have a similar degree of impairment across a number of behavioral tasks. In Experiment 1, no relationship between the severity of a spatial learning impairment and reaction time performance was found among aged rats. This result is in contrast with a relationship that was found in aged rats between spatial learning and the rate of recovery from gustatory neophobia (results of Experiments 2 and 3). Experiment 3 further showed that the relative spatial learning abilities of two subgroups of aged rats, i.e., "impaired" and "unimpaired," were related to transfer training in the water maze conducted six weeks after the completion of original training. The subgroups of aged animals were also distinguished by their latencies (but not errors) on a circular holeboard maze, and the pattern of water consumption during the light/dark cycle determined at the end of the entire protocol (13th week of testing). Other measures, however, did not distinguish the aged subgroups that were formed on the basis of spatial learning ability.