Harris R M, Woolsey T A
J Comp Neurol. 1981 Mar 1;196(3):357-76. doi: 10.1002/cne.901960302.
Neonatal damage to a row of mystacial vibrissae in the mouse causes cytoarchitectonic alterations in the contralateral SmI barrel Cortex. The region for the appropriate row of barrels develops as a smaller homogeneous zone while barrels in adjacent rows are expanded. To investigate the effects of this phenomenon on the morphology of individual neurons, adult mice in which Row-C vibrissae (the middle row) had been cauterized on days 1--5 following birth were processes by the Golgi-Cox method. All neurons in layer IV of the Row-C zones, of the Row-C barrels of a control hemisphere, and some neurons in the adjacent enlarged Row-B barrels were measured with a computer-assisted microscope. Their location with respect to cytoarchitectonic boundaries was determined from a Nissl counterstain. Data from 239 cells are presented. For each cell, measures of dendritic length and branching were obtained. The orientation of the dendritic trees with respect to the barrel sides was also measured. The measures of dendritic lengths and branching did not show any differences between control and experimental animals or between animals damaged on different days. Measures of orientation did show changes related to the age at the time of damage. In animals damaged on postnatal day (PND)-3 or earlier, many cells in the Row-C zone were observed with dendrites orienting toward the adjacent Rows-B or -D. "Putative" Row-C cells in the expanded parts of Rows-B and -D were strongly oriented toward barrels in those rows. These results suggest that dendritic length and branching may be determined intrinsically but that the orientation of the dendritic trees appears to be strongly influenced by the pattern of extrinsic afferent inputs from the thalamus. In the case of the whisker-damaged animals, the orientation of the Row-C neuron dendritic trees toward the "functional" thalamocortical inputs in Rows-B and -D contributes strongly to the resultant cytoarchitectonic changes. The implications of these results for normal developmental processes and their relationship to functional studies of the cortex are considered.
新生小鼠一排触须受损会导致对侧初级体感皮层桶状区出现细胞结构改变。受损触须对应桶状区发育为较小的均匀区域，而相邻排的桶状区则扩大。为研究此现象对单个神经元形态的影响，对出生后第1至5天灼除C排触须（中间一排）的成年小鼠采用高尔基-考克斯法进行处理。用计算机辅助显微镜测量C排区域第IV层的所有神经元、对照半球C排桶状区的神经元以及相邻扩大的B排桶状区的一些神经元。根据尼氏染色确定它们相对于细胞结构边界的位置。给出了239个细胞的数据。对每个细胞，获取树突长度和分支的测量值。还测量了树突树相对于桶状区边缘的方向。树突长度和分支的测量值在对照动物和实验动物之间或不同损伤日的动物之间未显示任何差异。方向测量值确实显示出与损伤时的年龄相关的变化。在出生后第3天或更早受损的动物中，观察到C排区域的许多细胞的树突朝向相邻的B排或D排。B排和D排扩大部分的“假定”C排细胞强烈朝向这些排的桶状区。这些结果表明，树突长度和分支可能由内在因素决定，但树突树的方向似乎受来自丘脑的外在传入输入模式的强烈影响。在触须受损的动物中，C排神经元树突树朝向B排和D排“功能性”丘脑皮质输入的方向对由此产生的细胞结构变化有很大贡献。考虑了这些结果对正常发育过程的意义及其与皮层功能研究的关系。
