Neurobehavioral biomarkers of aging: influence of genotype and dietary restriction.

Because of the importance of central nervous system (CNS) functions to productive capacity and quality of life, biomarkers of these functions will play a key role in evaluating the success of interventions targeting aging processes. The CNS biomarkers may also be useful for predicting aging in other systems and in the organism as a whole. Age-related behavioral changes, the products of CNS aging, have content and predictive validity with respect to human functional capacities and may, therefore, represent important "neurobehavioral" markers of functional aging. This article presents a discussion of some behavioral paradigms which are currently being considered as neurobehavioral biomarkers of aging in mice and the experimental approaches being employed in the assessment of their validity. Studies conducted in the authors' laboratory using dietary restriction and genetic comparisons to evaluate the validity of neurobehavioral biomarkers have revealed several methodological concerns, and hypothetical and empirical examples of these pitfalls are described and discussed. In spite of those concerns, it is concluded that approaches to validity using genetic comparisons and dietary restriction can be successfully implemented and should ultimately lead to identification of valid and useful neurobehavioral biomarkers of aging.