DEVELOPMENTAL HISTORY OF THE TRANSIENT SUBPLATE ZONE IN THE VISUAL AND SOMATOSENSORY CORTEX OF THE MACAQUE MONKEY AND HUMAN BRAIN
DEVELOPMENTAL HISTORY OF THE TRANSIENT SUBPLATE ZONE IN THE VISUAL AND SOMATOSENSORY CORTEX OF THE MACAQUE MONKEY AND HUMAN BRAIN
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DOI：
10.1002/cne.902970309
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发表时间：
1990-07-15
影响因子：
2.5
通讯作者：
RAKIC, P
中科院分区：
文献类型：
--
作者：
KOSTOVIC, I;RAKIC, P
在一系列人和猴胎脑中研究了发育中的视觉和体感皮层下的短暂亚板带的细胞学组织和出现和溶解的时间表。用Nissl、Golgi、电子显微镜和组织化学方法处理的脑壁显示，该区域由迁移和迁移后神经元、生长锥、松散排列的轴突、树突、突触和神经胶质细胞组成。在这两个物种中，亚板区在妊娠中期三分之一开始时变得可见，作为位于中间区和发育中的皮质板之间的细胞贫乏/纤维丰富层。亚板带出现早于在视觉区的躯体感觉，并达到最大宽度在妊娠的最后三分之一的开始这两个地区。在其大小的峰值，在体感皮层中，基板区和皮质板的宽度之比在猴中为2：1，在人中为4：1，而在枕叶中，这些结构在两种物种中具有大致相等的宽度。底板区的溶解开始于妊娠的最后三分之一，伴随着一些底板神经元的变性和纤维终末向皮质的迁移。亚板带在视觉区比在躯体感觉区消失得更快。目前的结果与我们以前的研究结果一起支持的假设，subplate区可能作为一个“等待”的车厢短暂的细胞相互作用和基板的竞争，隔离和传入源顺序从脑干，基底前脑，丘脑，并从同侧和对侧大脑半球的增长。经过一个可变的和部分重叠的时间段后，这些纤维进入皮质板，而基板区消失，只留下一个痕迹的细胞分散在整个皮质下白色物质。物种之间的比较表明，在哺乳动物的进化过程中，基板区的大小和持续时间增加，并在人类胎儿中达到高潮，伴随着皮质-皮质纤维系统的扩大。亚板区的大小、模式和分辨率的区域差异也与脑回的模式相关。我们的研究结果表明，与流行的观念相反，亚板可能不是遗传学上古老的网络的遗迹，而是一种短暂的胚胎结构，在进化过程中扩展，以满足其连接数量的增加。
The cytological organization and the timetable of emergence and dissolution of the transient subplate zone subjacent to the developing visual and somatosensory cortex were studied in a series of human and monkey fetal brains. Cerebral walls processed with Nissl, Golgi, electron-microscopic, and histochemical methods show that this zone consists of migratory and postmigratory neurons, growth cones, loosely arranged axons, dendrites, synapses, and glial cells. In both species the subplate zone becomes visible at the beginning of the mid-third of gestation as a cell-poor/fiber-rich layer situated between the intermediate zone and the developing cortical plate. The subplate zone appears earlier in the somatosensory than in the visual area and reaches maximal width at the beginning of the last third of gestation of both regions. At the peak of its size the ratio between the width of the subplate zone and cortical plate in the somatosensory cortex is 2:1 in monkey and 4:1 in man while in the occipital lobe these structures have about equal width in both species. The dissolution of the subplate zone begins during the last third of gestation with degeneration of some subplate neurons and the relocation of fiber termials into the cortex. The subplate zone disappears faster in the visual than in the somatosensory area. The present results together with our previous findings support the hypothesis that the subplate zone may serve as a "waiting" compartment for transient cellular interaction and a substrate for competition, segregation, and growth of afferents originated sequentially from the brain stem, basal forebrain, thalamus, and from the ipsi- and contralateral cerebral hemisphere. After a variable and partially overlapping time period, these fibers enter the cortical plate while the subplate zone disappears leaving only a vestige of cells scattered throughout the subcortical white matter. A comparison between speices indicates that the size and duration of the subplate zone increases during mammalian evolution and culminates in human fetuses concomitantly with an enlargement of cortico-cortical fiber systems. The regional difference in the size, pattern, and resolution of the subplate zone correlates also with the pattern of cerebral convolutions. Our findings indicate that, contrary to prevailing notions, the subplate may not be a vestige of the phylogenetically old network but a transient embryonic structure that expanded during evolution to subserve the increasing number of its connections.