Education, homeostasis, and longevity.

The effects of education in lengthening life expectancy and reducing disability and disease in old age are examined for neural and hormonal correlates. Hormones and local factors influencing growth, in regulating neural cell death, proliferation, and differentiation, support the view of a "brain reserve capacity" built up during early learning years and capable of affording a protective action (increased threshold to damage) against the losses of normal and abnormal aging. Observation from studies on the effects of estrogen, dexamethasone, and a number of local factors on growth and differentiation of human neuroblastoma cells and of glial cells are supportive of a role for these factors in maintenance of homeostasis at an advanced age. Continuing education and learning is proposed as an effective means to promote longevity and improve life in old age.