QUANTITATIVE-ANALYSIS OF THE AGE-RELATED FRAGMENTATION OF HAMSTER 24-H ACTIVITY RHYTHMS

The continuous monitoring of spontaneous locomotor activity has emerge d as one of the most widely used metrics in rodent circadian research. This behavioral measure is also extremely useful for the description of the effects of aging on circadian rhythms. The present study descri bes the successful use of a log-survivorship approach to identify disc rete bouts of hamster wheel-running activity and provides a detailed d escription of the age-related fragmentation in the 24-h profile of thi s behavioral variable. In addition, stepwise discriminant analysis ide ntified the most important quantitative measures for distinguishing be tween the individual patterns of wheel-running activity of young (3 mo ) and old (17-18 mo) golden hamsters. The results suggest that this me thod of bout analysis can be a valuable tool for the study of genetic, developmental, neurochemical, physiological, and environmental factor s involved in the temporal control of rodent locomotor behavior.