NEUROANATOMY OF THE VISUAL AFFERENTS IN THE HORSESHOE-CRAB (LIMULUS-POLYPHEMUS)
NEUROANATOMY OF THE VISUAL AFFERENTS IN THE HORSESHOE-CRAB (LIMULUS-POLYPHEMUS)
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DOI：
10.1002/cne.901920212
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发表时间：
1980-01-01
影响因子：
2.5
通讯作者：
BARLOW, RB
中科院分区：
文献类型：
--
作者：
CHAMBERLAIN, SC;BARLOW, RB
鲎的中枢神经系统由食管周围的融合神经节环和一对腹神经索组成。前部，即前脑，接收包括视觉信息在内的感觉输入。三条视神经，分别来自侧眼、中单眼和腹眼，进入大脑的每一侧。通过用氯化钴染色切断的神经干来确定每个视神经的中枢连接。外侧视神经支配板层、髓质、视束、腹侧中央体和单眼神经节。观察到单个轴突的分支模式，可能是侧眼视网膜中偏心细胞的轴突。外侧视神经中的单个大直径轴突在7个位点分叉，包括由外侧视神经作为整体支配的每个结构中的位点。正中视神经支配单眼神经节、中央体、视束和延髓。三种类型的分支模式，观察到单一的，大直径的纤维在正中视神经。一种绕过单眼神经节并支配中央体。第二类通过单眼神经节和视束，无分支，并支配后延髓。第三型支配单眼神经节、腹侧中央体、视束和延髓。腹侧视神经由腹侧光感受器的大直径轴突组成。每个轴突进入髓质的神经节细胞层并在直径小于150 μ m的平面区域上分支。来自前甲壳上的机械感受器的轴突支配延髓的后神经元，并且在延髓神经节细胞层中约5%的神经元将轴突发送到同侧的食管周围结缔组织。
The CNS of Limulus consists of circumesophageal ring of fused ganglia and a paired ventral nerve cord. The anterior portion, the protocerebrum, receives sensory inputs including visual information. Three optic nerves, one each from the lateral eye, median ocellus and ventral eye enter each side of the protocerebrum. The central connections of each optic nerve were determined by staining cut nerve trunks with cobalt chloride. The lateral optic nerve innervates the lamina, medulla, optic tract, ventral central body and ocellar ganglion. The branching patterns of single axons, probably those of eccentric cells in the lateral eye retina, were observed. Single, large-diameter axons in the lateral optic nerve ramify at 7 loci including sites in each of the structures innervated by the lateral optic nerve as a whole. The median optic nerve innervates the ocellar ganglion, central body, optic tract and medulla. Three types of branching patterns were observed for single, large-diameter fibers in the median optic nerve. One type bypasses the ocellar ganglion and innervates the central body. A 2nd type passes through the ocellar ganglion and optic tract without branching, and innervates the posterior medulla. A 3rd type innervates the ocellar ganglion, ventral central body, optic tract and medulla. The ventral optic nerve is composed of large-diameter axons of ventral photoreceptors. Each axon enters the ganglion cell layer of the medulla and branches over a planar area less than 150 .mu.m in diameter. Axons from mechanoreceptors on the anterior carapace innervate the posterior neuropil of the medulla, and about 5% of the neurons in the medullar ganglion cell layer send axons to the ipsilateral circumesophageal connective.