EARLY PRENATAL ONTOGENESIS OF CEREBRAL CORTEX (NEOCORTEX) OF CAT (FELIS-DOMESTICA) - A GOLGI STUDY .1. PRIMORDIAL NEOCORTICAL ORGANIZATION
EARLY PRENATAL ONTOGENESIS OF CEREBRAL CORTEX (NEOCORTEX) OF CAT (FELIS-DOMESTICA) - A GOLGI STUDY .1. PRIMORDIAL NEOCORTICAL ORGANIZATION
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DOI：
10.1007/bf00519296
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发表时间：
1971-01-01
期刊：
影响因子：
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通讯作者：
MARINPADILLA, M
中科院分区：
文献类型：
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作者：
MARINPADILLA, M
在早期的胎儿期皮质个体发育过程中，猫的新皮质经历了一系列的纤维-神经元组织的基本转变。这些转变中的一些具有结构特征和神经元特征，类似于那些在系统发育上更古老的皮质组织。随着皮质纤维到达脑泡的边缘地带，一个非常原始的新皮质组织，原始的丛状层发展起来。它的特点是白质的外部位置，既有皮质纤维，也有少数皮质分离纤维，纤维之间夹着一些未成熟的神经元。原始丛状层在妊娠第20天至第25天出现在猫体内。猫新皮质原始丛状层白质的外部(浅)位置使人联想到两栖动物的皮质组织。它也类似于中枢神经系统的其他原始结构(脊髓)。鉴于其持续时间短，以及其纤维-神经元成分的不成熟，原始网状层被认为是猫的暂时性新皮质组织，可能在猫中没有功能活动。皮质板的出现(孕25天)导致原始网状层细分为外区和内区。外层成为新皮质的第I层，内层成为第VI层。在整个皮质发育过程中，这两个层都保持不变。从第25天到第45天，第I层和第VI层的纤维神经元结构发育，而皮质板随着新细胞的逐渐增加而被动生长。猫大脑皮层I层和VI层的渐进性纤维-神经元组织以及它们之间结构和功能相互作用的发展构成了猫大脑皮层的原始新皮质组织。它的特点是浅层(第I层)和深层(第VI层)丛状层，主要由到达发育中皮质的皮质纤维的侧枝和三种基本类型的神经元组成。第I层水平神经元，下行轴突终止于第VI层，Martinotti神经元第VI层，上升轴突终止于第I层，为联合神经元。第VI层的大型星状神经元为投射神经元。这些细胞的轴突在进入白质之前将递增的回返侧支发送到第I层。在这个妊娠期，新皮质的纤维-神经元组织(原始新皮质组织)类似于爬行动物新皮质的组织。据推测，猫的原始新皮质组织在妊娠期间是功能活跃的。新类型的传入纤维到达皮质板下部(妊娠45d)导致了该区域锥体神经元的成熟。这些神经元在这个年龄段被认为是猫新皮质V层的锥体神经元。这些传入纤维的出现和V层锥体神经元的成熟标志着新皮质从原始的爬行动物结构转变为明显的哺乳动物组织。据推测，皮质板(锥体板)是新皮质系统发育中的一个新成员，代表了哺乳动物的转变。在两栖类皮质的锥体状神经元、爬行类新皮质的锥体状神经元和哺乳动物新皮质VI层的金字塔状神经元(星状)之间似乎存在类似的情况。这个比喻不同于经典的…比喻
The neocortex of the cat undergoes a series of fundamental transformations of its fibrillar-neuronal organization during the course of early prenatal cortical ontogenesis. Some of these transformations assume structural chracteristics and neuronal features which resemble those of phylogenetically older cortical organizations. Following the arrival of corticipetal fibers at the marginal zone of the cerebral vesicle a very primitive neocortical organization,the primordial plexiform layerdevelops. It is characterized by the external location of the white matter with both corticipetal and a few corticofugal fibers and a few immature neurons sandwiched between the fibers. The primitive plexiform layer is present in the cat from the 20th to the 25th day of gestation. The external (superficial) location of the white matter of the primordial plexiform layer of the cat neocortex is reminiscent of the amphibian cortical organization. It also resembles other primitive structures (spinal cord) of the central nervous system. In view of its short duration and because of the immaturity of its fibrillar-neuronal elements, the primordial plexiform layer is considered to be a transient neocortical organization possibly without functional activity in the cat.The appearance of the cortical plate (25th day of gestation) causes the subdivision of the primordial plexiform layer into an outer and an inner zone. The outer zone becomes layer I and the inner zone layer VI of the neocortex. Both of these layers remain as such throughout cortical development. From the 25th to the 45th day of gestation the fibrillarneuronal structure of layers I and VI develop while the cortical plate grows, passively, by the progressive addition of new cells. The progressive fibrillar-neuronal organization of layers I and VI and the development of structural and functional interactions between them constitutes theprimordial neocortical organizationof the cerebral cortex of the cat. It is characterized by a superficial (layer I) and a deep (layer VI) plexiform layer composed predominantly of collaterals from the corticipetal fibers arriving at the developing cortex and by three basic types of neurons. The horizontal neurons of layer I with descending axons terminating in layer VI, and the Martinotti neurons of layer VI with ascending axons terminating in layer I, are associative neurons. The large stellate neurons of layer VI are projective neurons. The axons of these cells before entering the white matter send ascending recurrent collaterals to layer I. The fibrillar-neuronal organization of the neocortex during this gestational period (primordial neocortical organization) resembles the organization of the reptilian neocortex. It is postulated that the primordial neocortical organization of the cat is functionally active during this gestational period.The arrival of new types of afferent fibers at the lower region of the cortical plate (45th day of gestation) causes the maturation of the pyramidal neurons of this region of the neocortex. These neurons are recognized at this age as the pyramidal neurons of layer V of the neocortex of the cat. The appearance of these afferent fibers and the maturation of the pyramidal neurons of layer V marks the transformation of the neocortex from its primitive reptilian structure into a distinctly mammalian organization. It is postulated that the cortical plate (pyramidal plate) is a recent addition in neocortical phylogeny representing a mammalian transformation. An analogy seems to exists among the pyramid-like neurons of the amphibian cortex, the pyramid-like neurons of the reptilian neocortex and the pyramid-like neurons (stellate) of layer VI of the mammalian neocortex. This analogy differs from the classical one …