Motor performance achievements in rats of different ages.

Motor performance of rats of different ages was determined in a cross sectional study. The design includes a test battery of seven motor tasks of graduated complexity. The results show a hierarchical order of impairments of motor functions in aging rats; that is, the more complex the task requirement, the earlier and more pronounced is the susceptibility to deterioration of motor coordination. In spontaneous activity and swimming no difference could be observed between young and old rats. With increasing requirements for the tilting-plane, horizontal wire, climbing and chimney tests as well as the rotarod test, the older rats show a differentiated decrease in performance. The findings are discussed in respect to the theory that aging is a reverse process of early development.