Age-related reduction in microcolumnar structure in area 46 of the rhesus monkey correlates with behavioral decline
Age-related reduction in microcolumnar structure in area 46 of the rhesus monkey correlates with behavioral decline
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DOI：
10.1073/pnas.0407002101
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发表时间：
2004-11-09
影响因子：
11.1
通讯作者：
Rosene, DL
中科院分区：
文献类型：
--
作者：
Cruz, L;Roe, DL;Rosene, DL
许多与年龄相关的认知功能下降都归因于前额叶皮质，其中46区尤为关键。然而，在正常衰老中，研究表明神经元不会在第46区丢失，这表明损伤是由更微妙的过程造成的。一个在功能上很重要，但由于缺乏有效的定量方法而在正常衰老过程中没有被研究过的皮质特征是，神经元垂直排列成微柱，这是皮质的基本计算单位。通过使用一种源自凝聚态物理的密度图方法，我们对七只年轻恒河猴和七只老年恒河猴的46区微柱进行了量化，这些恒河猴已经接受了认知测试。这项分析表明，总神经元密度或微柱宽度、长度或周期没有随年龄而减少。然而，微柱的强度有统计上的显著下降，表明微柱无序。在与年龄无关的空间工作记忆和再认记忆测试中，这种力量的下降与年龄相关的认知能力下降显着相关。模拟表明，神经元直径的30%左右的随机神经元移位(
Many age-related declines in cognitive function are attributed to the prefrontal cortex, area 46 being especially critical. Yet in normal aging, studies indicate that neurons are not lost in area 46, suggesting that impairments result from more subtle processes. One cortical feature that is functionally important, but that has not been examined in normal aging because of a lack of efficient quantitative methods, is the vertical arrangement of neurons into microcolumns, a fundamental computational unit of the cortex. By using a density-map method derived from condensed-matter physics, we quantified microcolumns in area 46 of seven young and seven aged rhesus monkeys that had been cognitively tested. This analysis demonstrated that there is no age-related reduction in total neuronal density or in microcolumn width, length, or periodicity. There was, however, a statistically significant decrease in the strength of microcolumns, indicating microcolumnar disorganization. This reduction in strength was significantly correlated with age-related cognitive decline on tests of spatial working memory and recognition memory independent of the effect of age. Modeling demonstrated that random neuron displacements of approximate to30% of a neuronal diameter (