Maturation of rat visual cortex. I. A quantitative study of Golgi-impregnated pyramidal neurons
Maturation of rat visual cortex. I. A quantitative study of Golgi-impregnated pyramidal neurons
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大鼠视觉皮层的成熟。
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发表时间：
1981
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通讯作者：
Michael Miller
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文献类型：
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作者：
Michael Miller
摘要 对大鼠视觉皮层 II/III 层和 V 层锥体神经元的出生后早期成熟进行了检查，试图阐明其成熟形态的一些决定因素。使用高尔基体浸渍的锥体细胞量化了三个指数：沿顶端树突的棘密度、初级基底树突的数量和细胞体的体积。所有锥体神经元顶端树突上的平均棘密度逐步增加。第一次显着增加发生在第 6 天和第 9 天之间，第二次显着增加发生在第 12 天和第 15 天之间；这些增加可能分别与膝状传入神经的到来和眼睛的张开有关。在较年轻的动物中，棘沿顶轴的分布相对均匀，而在年长的动物中，棘密度在近端 125 μm 部分显着增加，而在其余远端部分则相对恒定。到第 21 天，V 层锥体细胞比 II/III 层细胞获得了更多的初级基底树突和更大的体细胞体积。此外，随着细胞成熟，II/III 层和 V 层神经元的这些特征的变化率显着不同。对于这两个细胞群，初级基底树突的平均数量在下降到稳定水平之前增加到最大值，但对于 V 层神经元，最大值更高，并且比 II/III 层细胞早三天达到最大值。此外，V层神经元细胞体体积的增加比II/III层细胞的细胞体体积早三天开始。这三天的成熟阶段差异可能反映了细胞的出生日期，因为放射自显影证据表明，V 层锥体神经元比占据成人视觉皮层 II/III 层的神经元早大约三天到达皮层板。
SummaryThe early postnatal maturation of pyramidal neurons in layers II/III and V of the rat visual cortex has been examined in an attempt to elucidate some determinants of their mature morphology. Three indices have been quantified using Golgi-impregnated pyramidal cells: densities of spines along apical dendrites, numbers of primary basal dendrites and volumes of cell bodies. The mean density of spines on the apical dendrites of all pyramidal neurons increases in a stepwise fashion. The first significant increase occurs between days 6 and 9 and the second, between days 12 and 15; these increases may correlate with the arrival of geniculate afferents and with the opening of the eyes, respectively. In younger animals, the distribution of spines along the apical shafts is relatively even, whereas in older animals, spine density increases significantly over the proximal 125 μm portion and is relatively constant over the remaining distal portion. By day 21, layer V pyramidal cells have acquired more primary basal dendrites and larger somatic volumes than layer II/III cells. Furthermore, as the cells mature the rates of change in these characteristics are significantly different for neurons in layer II/III and in layer V. For both cell populations, the mean number of primary basal dendrites increases to a maximum before falling to a steady level, but for neurons in layer V, the maximum is higher and attained three days earlier than for layer II/III cells. Moreover, the increase in volume of cell bodies of layer V neurons begins three days before that of layer II/III cells. This three day phase difference in maturation may reflect the cell birth dates, since autoradiographic evidence indicates that layer V pyramidal neurons reach the cortical plate about three days prior to those which occupy layer II/III in the adult visual cortex.