require all these types of measurements. These markers can be utilized to test the efficacy of interventions aimed at maintaining and recovering neural health.
2. Identifying factors that affect neural health during aging.
Research under this element of the neural health initiative would examine the extent to which changes in brain function are due to neural dysfunction other than neural loss. These studies would examine hypotheses regarding mechanisms that underlie neural dysfunction, especially those affecting brain function and neural health through gene expression and through such homeostatic processes as apoptosis, inflammation, and oxidative activity, which may have either beneficial or detrimental effects.
Research under this element of the initiative would also examine factors in life experience that may affect neural health. These studies would focus on such factors as past cognitive training, occupational experience, mental activity across the life span, and other life history and cultural factors that may affect neural health during the aging process, thus linking the neural health initiative to the initiative on cognition in context (see Chapter 3). This element of the initiative would seek to specify the life course of processes affecting neural health in aging. It would support research to develop and test models of the processes that affect neural health in aging and that link neural health to cognitive perfornance.
3. Devising interventions for the maintenance of healthy neurons and the rescue and repair of neural networks.
Studies are needed to develop strategies for maintaining healthy neurons and recovering dysfunctional neurons. These strategies may involve interventions at the molecular, cellular, and behavioral levels. Studies may involve such diverse interventions as transplantation of differentiated and genetically engineered stem cells; gene delivery by transgenic and viral vector mediated approaches; the administration of drugs and nutritional supplements, especially those predicted to be beneficial from epidemiological studies; and training and other behavioral and cognitive interventions. Government support is particularly necessary for trials aimed at clinically testing the efficacy of non-prescription items, such as over-the-counter drugs and nutritional supplements, that have anti-inflammatory or antioxidant properties. Some of these have been associated with reduced incidence of dementia in epidemiological studies (Breitner, 1996; Morris et al., 1998), but the private sector is unlikely to support clinical trials of inexpensive, freely available therapeutics for which there is no patent protection. The NIA might support some such studies in