Juraska Janice M, Lowry Nioka C
Department of Psychology and Program in Neuroscience, University of Illinois, 603 E Daniel, Champaign, IL, 61820, USA,
Curr Top Behav Neurosci. 2012;10:137-62. doi: 10.1007/7854_2011_137.
The literature on the neuroanatomical changes that occur during normal, non-demented aging is reviewed here with an emphasis on the improved accuracy of studies that use stereological techniques. Loss of neural tissue involved in cognition occurs during aging of humans as well as the other mammals that have been examined. There is considerable regional specificity within the cerebral cortex and the hippocampus in both the degree and cellular basis for loss. The anatomy of the prefrontal cortex is especially vulnerable to the effects of aging while the major subfields of the hippocampus are not. A loss of neurons, dendrites and synapses has been documented, as well as changes in neurotransmitter systems, in some regions of the cortex and hippocampus but not others. Species differences are also apparent in the cortical white matter and the corpus callosum where there are indications of loss of myelin in humans, but most evidence favors preservation in rats. The examination of whether the course of neuroanatomical aging is altered by hormone replacement in females is just beginning. When hormone replacement is started close to the time of cycle cessation, there are indications in humans and rats that replacement can preserve neural tissue but there is some variability due to the type of hormones and regimen of administration.
本文回顾了有关正常、非痴呆衰老过程中发生的神经解剖学变化的文献，重点强调了使用体视学技术的研究在准确性上的提高。在人类以及其他已被研究的哺乳动物的衰老过程中，均会出现参与认知的神经组织丧失。在大脑皮层和海马体中，丧失的程度和细胞基础在区域上具有相当大的特异性。前额叶皮层的解剖结构尤其容易受到衰老的影响，而海马体的主要亚区则不然。在皮层和海马体的某些区域，已记录到神经元、树突和突触的丧失以及神经递质系统的变化，但其他区域则未出现这些变化。在皮层白质和胼胝体中，物种差异也很明显，有迹象表明人类存在髓鞘丧失，但大多数证据表明大鼠的髓鞘得以保留。关于激素替代疗法是否会改变女性神经解剖学衰老进程的研究才刚刚开始。在接近绝经时开始激素替代疗法，在人类和大鼠中均有迹象表明这种替代可以保留神经组织，但由于激素类型和给药方案的不同，存在一定的变异性。
