Viale San Michele del Carso 15, 20144 Milan, Italy.
Brain Struct Funct. 2011 Jun;216(2):85-9. doi: 10.1007/s00429-011-0308-y. Epub 2011 Mar 23.
During normal aging, widespread loss of nerve cells does not occur. Neuronal loss is limited to restricted regions of the nervous system and is slight (probably no more than 10%). The commonest age-related structural changes undergone by nerve cells are as follows: dendrites decrease in number and length and many dendritic spines are lost; axons decrease in number and their myelin sheaths may become less compact and undergo segmental demyelination followed by remyelination; and significant loss of synapses occurs. These changes probably make a significant contribution to the behavioral impairment and cognitive decline that often accompany normal aging.
在正常衰老过程中，不会发生广泛的神经细胞损失。神经元损失仅限于神经系统的受限区域，且程度轻微（可能不超过 10%）。神经细胞经历的最常见的与年龄相关的结构变化如下：树突数量和长度减少，许多树突棘丢失；轴突数量减少，其髓鞘可能变得不那么紧密，并发生节段性脱髓鞘，随后进行髓鞘再生；突触大量丢失。这些变化可能对伴随正常衰老出现的行为障碍和认知能力下降做出重要贡献。
