The Functions of the Pyramidal Tracts
The Functions of the Pyramidal Tracts
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锥体束的功能
DOI：
10.1086/394499
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发表时间：
1936
期刊：
影响因子：
--
通讯作者：
C. Marshall
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文献类型：
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作者：
C. Marshall
克莱德马歇尔耶鲁大学医学院神经解剖学系尽管“锥体束”一词在神经病学中被广泛使用，但对其正确定义似乎存在一定的混淆。因此，有些人将其定义为所有向下穿过髓质锥体到达脊髓的纤维，或者所有皮质脊髓纤维的总和。另一些人将其定义为仅由大脑皮层中某个区域（如初级运动皮层或布罗德曼4区）产生的皮质脊髓纤维组成。根据最后一个定义，任何从运动前区（布罗德曼6区）或中央后回发出的皮质脊髓纤维都被认为是“锥体外系”。“从历史的角度来看，优先考虑第一个定义，因为这个名字的出现并不像许多人想象的那样，因为这条路起源于大脑皮层的锥体细胞，而是因为它代表了髓质金字塔的延续。事实上，这个名字是在该神经束与大脑皮层建立任何联系之前给出的。蒂尔克（1851年，1853年）首先描述了它，他将现在被称为交叉锥体束的东西命名为“侧-侧-柱-束”，并将现在被称为直接锥体束或蒂尔克束的东西命名为“囊-侧-柱-束”。他认为这两条神经束是在基底神经节区域，特别是豆状核中出现的下行神经束。Flechsig在1876年以“锥体束”的名称描述了这两种成分。他同意Tiirck关于其可能的晶状体起源的观点，但由于他不能确定可能的皮质连接，他拒绝使用他更喜欢的术语“晶状体-核-外侧柱-束”。直到后来（1877年，188 i年），弗莱希才用骨髓发生学方法出色地证明了锥体系统与大脑皮层的联系，特别是中央前回和中央旁小叶。遵循Flechsig的实验解剖学家同意将锥体系统定义为穿过锥体进入脊髓的纤维或皮质脊髓系统的总和。然而，关于它起源于大脑皮层的程度，人们还没有达成一致意见。坎贝尔（'os）根据他对肌萎缩侧索硬化症的研究（后来被证明是不正确的）和其他一些证据，肯定了这条神经束完全来自贝茨的巨细胞，这些巨细胞位于细胞结构定义的运动区内。术语“运动区”或“运动皮层”是不能令人满意的，因为已经给出了如下四个定义：（1）一个特定的细胞结构皮层区，如Brodmann的4区，或Economo的FA区;（2）锥体束的起源区;（3）皮层的电兴奋区;（4）当移动时将产生最大麻痹的皮层区。在本讨论中，始终使用第一个定义。Holmes和May（'og）从他们对各种脊髓损伤后的溶色素细胞变化的研究中，
BY CLYDE MARSHALL Department of Anatomy, Section of Neuro-Anatomy, Yale University School of Medicine IN SPITE of the fact that the term "pyramidal tract" is commonly used in neurology, a certain confusion seems to exist as to its proper definition. Thus some define it as all those fibers passing downwards through the pyramids of the medulla to the spinal cord, or as the sum total of all cortico-spinal fibers. Others define it as consisting of only those cortico-spinal fibers arising from a certain region in the cerebral cortex, such as the primary motor cortex or area 4 of Brodmann. By the last definition any cortico-spinal fibers passing from the premotor area (area 6 of Brodmann) or from the postcentral gyrus would be regarded as "extra-pyramidal." On historical grounds the priority goes to the first definition, for the name arose not as many suppose, because the tract arises from pyramidal cells in the cerebral cortex, but because it represents a continuation of the pyramids of the medulla. The name was given, indeed, before any connection of the tract with the cerebral cortex was established. Tiirck (i85I, I853) who first described it, gave the name "pyramidal-lateral-column-tract" for what is now known as the crossed pyramidal tract, and the name "capsularanterior-column-tract," to what is now called the direct pyramidal tract or the tract of Tiirck. He regarded these two as descending tracts which arose in the region of the basal ganglia, particularly in the lenticular nucleus. Flechsig in I876 described both components under the name "pyramidal tract." He agreed with Tiirck as to its probable lenticular origin, but since he could not be certain of possible cortical connections he declined to use the term "lenticular-nucleus-lateral-column-tract" which he otherwise preferred. It was not till a later date (I877, i88i) that Flechsig brilliantly demonstrated by the myelogenetic method the connections of the pyramidal system with the cerebral cortex, particularly the precentral gyrus and the paracentral obule. The experimental anatomists following Flechsig agree in defining the pyramidal system as those fibers passing through the pyramids into the spinal cord or as the sum total of the corticospinal system. Agreement has not been reached, however, as to the extent of its origin from the cerebral cortex. Campbell ('os) on the basis of his studies on amyotrophic lateral sclerosis (which were later proved to be incorrect) and some other evidence, affirmed that the tract arose exclusively from the giant cells of Betz within the cytoarchitecturally defined motor area. The term "motor area" or "motor cortex" is an unsatisfactory one, since four definitions have been given it as follows: (i) A specific cytoarchitectural cortical area, such as area 4 of Brodmann, or, area FA of Economo; (X) the area of origin of the pyramidal tract; (3) the electrically excitable area of the cortex; (4) that cortical area which when rcmoved will give the maximal paralysis. In the present discussion the first definition is consistently used. Holmes and May ('og) from their studies of chromatolytic ell changes following spinal cord lesions in a large variety of ex-