ONTOGENY OF THE PYRAMIDAL CELL OF THE MAMMALIAN NEOCORTEX AND DEVELOPMENTAL CYTOARCHITECTONICS - A UNIFYING THEORY
ONTOGENY OF THE PYRAMIDAL CELL OF THE MAMMALIAN NEOCORTEX AND DEVELOPMENTAL CYTOARCHITECTONICS - A UNIFYING THEORY
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DOI：
10.1002/cne.903210205
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发表时间：
1992-07-08
影响因子：
2.5
通讯作者：
MARINPADILLA, M
中科院分区：
文献类型：
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作者：
MARINPADILLA, M
在各种实验动物(仓鼠、小鼠、大鼠和猫)和人类身上，用快速高尔基方法分析了哺乳动物新皮质的产前发育。讨论了哺乳动物新皮质结构组织的一种新的发育概念。新皮质的发育始于原始丛状层(PPL)的建立，它先于皮质板(CP)的形成，是随后形成的先决条件。CP的形成全部发生在PPL内。在其发育过程中，神经元发生了三个基本事件：迁移、早期分化和晚期成熟。所有迁移的神经元，在放射状神经胶质纤维上移动，到达第I层，发展出顶端树突，并与其元素建立联系。这些新分化的神经元具有类似于胚胎锥体细胞的形态。因此，建立了CP所有神经元共同的早期分化阶段。在成熟后期，所有的CP神经元都获得了其特定的表型、结构和功能特征。只有锥体神经元保留和扩大了它们与第I层的原始联系，而其他类型的神经元失去了这些联系。锥体细胞在发育过程中被重新定义：新皮质的锥体细胞在结构和功能上都被锁定在第i层和其胞体的皮质深度之间。在哺乳动物的进化过程中，锥体细胞被迫在结构和功能上向外延长其顶端树突，以适应越来越多的信息，而不会失去它们最初固定在I层的位置或皮质深度。锥体神经元的这种独特特性被认为是哺乳动物的创新。在此基础上，提出了一个适用于所有哺乳动物的统一的发育细胞构筑理论。该理论认为CP是哺乳动物的创新，代表了一个单一的、分层的和不断扩大的端脑核团。该理论设想哺乳动物的新皮质是一个开放的生物系统，能够通过从上层II招募原始神经元并将其转变为锥体细胞来逐步扩张。因此，在哺乳动物的系统发育过程中，锥体细胞层的数量不断增加。强调了I层在神经元的迁移、CP的形成、锥体细胞的独特形态和哺乳动物新皮质的整体结构组织中的发育作用。
The prenatal development of the mammalian neocortex has been analyzed, with the rapid Golgi method, in a variety of experimental animals (hamster, mouse, rat, and cat) and in humans. A new developmental conception of the structural organization of the mammalian neocortex is discussed. Neocortical development begins with the establishment of the primordial plexiform layer (PPL) which precedes and is a prerequisite for the subsequent formation of the cortical plate (CP). The formation of the CP occurs, in its entirety, within the PPL. During its development, three fundamental neuronal events occur: migration, early differentiation, and late maturation. All migrating neurons, travelling on radial glial fibers, reach layer I, develop an apical dendrite, and establish contacts with its elements. These newly differentiated neurons assume similar morphology resembling embryonic pyramidal cells. As such, an early differentiation stage common to all neurons of the CP is established. During the late maturation stage, all CP neurons acquire their specific phenotypic structural and functional features. Only pyramidal neurons retain and expand their original connections with layer I while other neuronal types lose these connections. The pyramidal cell is redefined in developmental terms: the neocortex's pyramidal cell is both structurally and functionally locked into position between layer I and the cortical depth of its soma. During mammalian evolution pyramidal cells are forced to structurally and functionally elongate their apical dendrite outwardly to accommodate an increasing amount of information without losing either their original anchorage to layer I or their cortical depth. This unique property of pyramidal neurons is considered to be a mammalian innovation. Based on these observations, a unifying developmental cytoarchitectonic theory applicable to all mammals is proposed. The theory considers the CP to be a mammalian innovation and to represent a single, stratified, and expanding telencephalic nucleus. The theory envisions the mammalian neocortex as an open biological system capable of progressive expansion by the recruitment and transformation of primitive neurons from upper layer II into pyramidal cells. Hence, the number of pyramidal cell strata increases over the course of mammalian phylogeny. The developmental roles of layer I in the migration of neurons, formation of the CP, unique morphology of pyramidal cells, and overall structural organization of the mammalian neocortex are emphasized.