AGING OF the nervous system is the theme for this issue of the ARCHIVES. Eight reviews are included which represent critical thinking of this complex and rapidly emerging scientific discipline. Evolutionary causes, molecular genetics and genomics, regeneration, and endocrinologic and neuropsychologic changes with normal and pathologic aging are included, written by major figures in the field.
Acquired mutations have accumulated for tens of thousands of years and have provided our species fitness to survive through natural selection. Fitness to reproduce and pass on one's genes to the next generation and for those progeny to survive has been the emphasis of evolution. After the reproductive years, evolution does not provide a great deal of support for enhanced survival. Aging is not a positive attribute to spend genetic energy to ameliorate its consequences. Evolution has not treated aging as an important biologic event beyond the reproductive and parenting years. The clinical consequences are the frequently seen diseases associated with aging, including cerebrovascular disease, Alzheimer disease (AD), Parkinson disease, amyotrophic lateral sclerosis, the frontotemporal dementias, and progressive brain atrophy with aging.1,2