Preserved neuron number in the hippocampus of aged rats with spatial learning deficits
Preserved neuron number in the hippocampus of aged rats with spatial learning deficits
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DOI：
10.1073/pnas.93.18.9926
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发表时间：
1996-09-03
影响因子：
11.1
通讯作者：
Gallagher, M
中科院分区：
文献类型：
--
作者：
Rapp, PR;Gallagher, M
海马神经元损失被广泛视为正常衰老的标志。此外，神经元变性被认为直接导致海马体支持的与年龄相关的学习和记忆缺陷。通过利用改进的量化神经元数量的方法，本研究报告了挑战这些长期存在的概念的证据。使用 Morris 水迷宫评估年轻和老年 Long-Evans 大鼠的海马依赖性空间学习状态，并根据光学分馏器技术定量齿状回和海马主细胞层中的神经元总数。对于每个海马区，老年受试者作为一个群体以及记录有表明海马功能障碍的学习和记忆缺陷的老年个体的神经元数量都被保留。研究结果表明，海马神经元变性并不是正常衰老的必然结果，海马体主要神经元的丧失并不能解释与年龄相关的学习和记忆障碍。观察到的神经元数量的保留为识别海马衰老导致认知能力下降的神经生物学影响奠定了重要基础。
Hippocampal neuron loss is widely viewed as a hallmark of normal aging. Moreover, neuronal degeneration is thought to contribute directly to age-related deficits in learning and memory supported by the hippocampus. By taking advantage of improved methods for quantifying neuron number, the present study reports evidence challenging these long-standing concepts. The status of hippocampal-dependent spatial learning was evaluated in young and aged Long-Evans rats using the Morris water maze, and the total number of neurons in the principal cell layers of the dentate gyrus and hippocampus was quantified according to the optical fractionator technique. For each of the hippocampal fields, neuron number was preserved in the aged subjects as a group and in aged individuals with documented learning and memory deficits indicative of hippocampal dysfunction. The findings demonstrate that hippocampal neuronal degeneration is not an inevitable consequence of normal aging and that a loss of principal neurons in the hippocampus fails to account for age-related learning and memory impairment. The observed preservation of neuron number represents an essential foundation for identifying the neurobiological effects of hippocampal aging that account for cognitive decline.