Normal Aging: Cognition and the Brain

In Paul Baltes words, the Janus head of aging is that we all wish to get old, but at the same time we do not wish to be old. With respect to the demographic development at least in the industrialized countries, we need a clear understanding of the problems involved in normal (sound) aging in addition to what we have learned about pathological aging. There are many social, psychological and neurobiological facets of normal aging, a few of them discussed in this contribution. The problem is looked at from the perspective of cog-nition (mainly executive functions), morphometry/stereology, and neuroimaging (functional MRI). Normal aging is a structurally heterogeneous brain process. Regional (areal) differences as well as differences in the age-sensitivity of cerebral tissue components may or may not provide a plausible structural basis for understanding individually markedly differing profiles of functional (cognitive) deterioration with advancing age. It is stated that the frontal lobes seem to be affected by the process of normal aging both earlier than other brain areas and at a more rapid pace. Because neuroimaging can in principle provide rich empirical evidence on normal aging, functional MRI in elderly persons is briefly discussed with respect to potential age-sensitive changes of the hemodynamic response when making use of the standard BOLD contrast.