The origin of the cranial ganglia in ameiurus
The origin of the cranial ganglia in ameiurus
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阿梅鲁斯颅神经节的起源
DOI：
10.1002/cne.920200404
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发表时间：
1910
影响因子：
--
通讯作者：
F. L. Landacre
中科院分区：
文献类型：
--
作者：
F. L. Landacre
310 FL LANDACRE站在巨大的劳动花费在这个问题上，很难说有任何普遍的协议在工人之间的起源模式或基本关系的各种大脑神经彼此。除了这个问题本身的困难之外，缺乏一致意见还有几个原因。在这些原因中，最主要的原因是大脑神经的研究从属于更普遍的问题，如脊椎动物头部的同色异谱和头部与躯干的关系。这些基本问题引起了形态学家和胚胎学家的浓厚兴趣，因此，即使在神经的起源、组成和分布还没有被准确地知道的情况下，脑神经也被用作研究它们的一种手段，这是很自然的。然而，由于这种研究方法，研究脑神经的学者们在很长一段时间里，对于脑神经干和头部各段之间应该存在的关系，有着先入为主的观念。从某种意义上说，脑神经序列同源性的想法阻碍了人们清楚地了解它们的真实关系。神经系统作为协调机制的主要功能在试图将脑神经简化为某种基本类型时被忽视了，这种基本类型将使它们彼此协调并与脊神经协调。在原始脊椎动物中，可能存在着某些脑神经之间的基本关系，如序列同源性概念所涉及的关系;但是，在这样的基础上，很难理解鱼纲动物的脑神经。生物体的基本需要已经如此改变了这种原始类型，以至于采用某种功能单位（如感觉系统）作为分析脑神经的基础要容易得多，也更雅阁事实。试图将脑神经干等同化的基本困难来自于这样一个事实，即它们在本质上不是单位而是复合体，因此组成它们的成分为理解它们的真实关系提供了逻辑基础。
310 FL LANDACRE standing the enormous amount of labor expended on this problem, it can hardly be said that there is any general agreement among workers as to the mode of origin or fundamental relationships of the various cerebral nerves to each other. The lack of agreement may be traced to several causes aside from the difficulty inherent in the problem. Chief among these causes must be placed the subordination of the study of the cerebral nerves to more general problems, such as the metamerism of the vertebrate head and the relation of the head to the trunk. These fundamental problems have been a source of intense interest to both morphologists and embryologists and it was only natural that the cerebral nerves should be used as a means of shedding light on them, even when the origin, composition and distribution of the nerves were not accurately known. Owing to this method of approach, however, students of the cerebral nerves were for a long time handicapped by preconceived notions as to the relations which ought to exist between the trunks of the cerebral nerves and the various head segments. The idea of the serial homology of the cerebral nerves has been in a sense a barrier to a clear understanding of their true relationships. The chief function of the nervous system as a coördinating mechanism was lost sight of in the attempt to reduce the cerebral nerves to some fundamental type that would bring them into harmony with each other and with the spinal nerves. Some such fundamental relationship among the cerebral nerves as that involved in the idea of serial homology probably existed in a primitive vertebrate; but the cerebral nerves of the Ichthyopsida are not most easily understood on such a basis. The fundamental needs of the organism have so modified this primitive type that it is much easier and more in accord with the facts to take some functional unit, such as a sensory system, as a basis for the analysis of the cerebral nerves. The fundamental difficulty in the attempt to homologize the trunks of the cerebral nerves comes from the fact that they are not units but composite in nature, so that the components of which they are made up furnish the logical basis for getting at their true relationships.