Patterns of Axon Collateralization of Identified Supragranular Pyramidal Neurons in the Cat Auditory Cortex
Patterns of Axon Collateralization of Identified Supragranular Pyramidal Neurons in the Cat Auditory Cortex
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DOI：
10.1093/cercor/1.1.80
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发表时间：
1991-01-01
期刊：
影响因子：
3.7
通讯作者：
Jones, Edward G.
中科院分区：
文献类型：
--
作者：
Ojima, Hisayuki;Honda, Christopher N.;Jones, Edward G.
细胞内注射辣根过氧化物酶或生物细胞素后，猫初级听觉皮层（Al）第二层和第三层的9个锥体神经元被完全重建。每个神经元根据其相对于最佳频率响应的前后序列的位置进行功能表征。所有被标记的体细胞都位于第II层或第III层，并产生典型的顶端和基部树突乔木以及广泛的轴突侧枝系统。除1个细胞外，其余细胞的初级轴突均进入白质，可能是单侧或对侧指向皮层其他区域。两个主要的皮层内侧支系统从Al的主要轴突出现，一个在细胞附近结束，另一个在远处结束。(1)在第III层和第V层释放出的许多局部和反复的侧枝，促成了终末分支的形成，终末分支从表面和深处延伸到体细胞的柱状模式。(2)每个细胞的轴突在第三层和（或）第五层也产生了2-5层厚的长侧枝，这些侧枝平行于脑顶表面数毫米。在这些长水平侧枝的几个点上，垂直方向的分支出现，形成柱状终止，再次延伸到第I-V层。这些柱与细胞附近形成的柱不重叠，位于距离细胞体500-1200 μ m的地方。在切向平面上观察时，水平侧枝相对于皮层表面总体上是背侧的。这可能与先前在猫身上描述的同频段组织相对应。结果表明，Al中兴奋的主要传播是由锥体细胞的水平侧支介导的，并沿等频域线发生。在后者中，侧枝可以连接具有类似属性的细胞列和/或用于协调ai空间分离部分的活动模式。
Nine pyramidal neurons in layers II and III of cat primary auditory cortex (Al) were fully reconstructed after intracellular injections of horseradish peroxidase or biocytin. Each neuron was functionally characterized according to its position relative to an anteroposterior sequence of best frequency responses. All labeled somata were in layers II or III and gave rise to typical apical and basal dendritic arbors as well as to extensive systems of axon collaterals.The primary axon of all except 1 cell entered the white matter and was probably directed toward other cortical areas ipsi- or contralaterally. Two major intra-cortical collateral systems emerged from the main axon in Al, one ending in the vicinity of the cell and the second at a distance. (1) Many local and recurrent collaterals, given off in layers III and V, contributed terminal branches to the formation of a columnar pattern of terminations extending superficially and deeply into the soma. The column extended through layers I-V, with some constriction in the middle portion corresponding to layer IV. (2) The axon of each cell also gave rise to 2-5 thick, long-range collaterals in layers III and/or V. These ran parallel to the pial surface for several milli-meters. At several points along these long horizontal collaterals, vertically directed branches emerged to form columnar terminations, again extending through layers I-V. These columns did not overlap with that formed in the vicinity of the cell, and were situated at distances 500-1200 mu m from the cell body.When viewed in the tangential plane, horizontal collaterals were oriented, on the whole, dorsoventrally with respect to the surface of the cortex. This may correspond to the organization of isofrequency bands previously described in cats. The results suggest that the major spread of excitation in Al is mediated by horizontal collaterals of pyramidal cells and that it occurs along the lines of isofrequency domains. Within the latter the collaterals may link columns of cells with like properties and/or serve to coordinate activity patterns in spatially separated portions of Al.