Structural inhomogeneity in the neuropil of lamina II/III in rabbit visual cortex
Structural inhomogeneity in the neuropil of lamina II/III in rabbit visual cortex
复制标题
兔视觉皮层 II/III 层神经纤维的结构不均匀性
DOI：
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发表时间：
2004
影响因子：
2
通讯作者：
A. Schleicher
中科院分区：
文献类型：
--
作者：
C. Schmolke;A. Schleicher
由于顶树突在大脑皮质的第四层至第二层中成束分布，神经纤维可分为两个区室：（1）由锥体细胞的顶树突及其之间的细细胞突起组成的树突束的神经纤维区;（2）将树突束分隔开的神经纤维区。本研究的目的是获得更多的信息有关的组成和安排的细微细胞过程中的两个隔间的差异，并量化的细胞外空间的配置和大小的差异。为此，在8只成年家兔的视皮层中，在板层II/III的上半部分进行了两个室的比较体视学研究。在电子显微照片中，对神经细胞的各种组成元素进行了评价，评价内容涉及（a）它们的体积分数和（B）它们的表面分数，即包含在给定体积的组织中的它们的膜的表面积。结果发现，薄的轴突，神经胶质细胞的过程和刺的体积分数显着高于之间比内的树突束，而树突的体积分数是约50%，高出的车厢中的束。然而，当从计算中排除两个隔室中的树突时，发现树突束内和树突束之间的剩余神经元的组成是相同的。就表面组分而言，除树突和有髓轴突外，各种细胞突起均存在显著差异。树突束之间的小轴突、胶质突起和棘的表面分数高于树突束内的表面分数。如果把各种过程放在一起考虑，膜的表面密度也是如此。这些发现表明，树突束之间的细胞外空间是相当多的曲折比束内。计算表明，枝晶束之间的细胞外空间的体积分数比束内高约32%。
SummaryDue to the bundling of apical dendrites throughout laminae IV-II of the cerebral cortex, two compartments of neuropil are distinguished: (1) the neuropil of the dendrite bundles consisting of closely associated, vertically oriented apical dendrites of pyramidal cells and the fine cell processes between them and (2) the neuropil separating the dendrite bundles. The aim of the present study is to obtain more information concerning differences in composition and arrangement of fine cell processes in the two compartments and to quantify differences in the configuration and size of the extracellular space. To this end, a comparative stereological study of the two compartments has been performed in the upper half of lamina II/III in the visual cortex of 8 adult rabbits. The various constituent elements of the neuropil have been evaluated in electron micrographs with respect (a) to their volume fractions and (b) to their surface fractions, i.e. the surface areae of their membranes comprised in a given volume of tissue. It was found that the volume fractions of thin axons, glial processes and spines are significantly higher between than within dendrite bundles, whereas the volume fraction of dendrites is about 50% higher in the compartment of the bundles. However, when excluding the dendrites in both compartments from calculations, the composition of the remaining neuropil within and between dendrite bundles was found to be identical. As far as surface fractions are concerned, significant differences were shown to exist for all kinds of cell processes except dendrites and myelinated axons. Surface fractions of small axons, glial processes and spines are higher between than within dendrite bundles. The same is true for the surface density of membranes if all kinds of processes are taken together. These findings indicate that the extracellular space between dendrite bundles is considerably more tortuous than that within bundles. Calculation reveals that between dendrite bundles the volume fraction of the extracellular space is about 32% higher than within the bundles.
影响因子：
5.5
作者：
NICHOLSON, C;PHILLIPS, JM
通讯作者：
PHILLIPS, JM