Meininger V, Baudrimont M
J Comp Neurol. 1981 Aug 10;200(3):339-55. doi: 10.1002/cne.902000305.
Postnatal modifications of dendrites have been quantitatively studied by network analysis of the dendritic tree in the two central nuclei of the inferior colliculus in the cat. This analysis revealed cells with two types of branching patterns suggesting two different modes of growth. The predominant pattern is characterized by dichotomous branching on random segments (DR cells). However, a purely collateral branching pattern is particular to certain cells (CB cells). These two branching patterns were found in both nuclei of the IC in adult and young cats, but the exact significance of these two cell types remains unclear. The dendritic trees of cells in kittens differed from those of the adult cat. Also, the types of modification were different in the two functionally distinct nuclei of the inferior colliculus that we studied. The most dramatic modifications were observed in the dendritic tree of DR cells in the central nucleus, which receives fibers from the auditory nuclei in the brainstem. Two parameters were modified: the mean number of terminal segments and the mean total length of segments. Both parameters increased in the sagittal plane and decreased in the frontal plane. These modifications indicate a reorientation of the dendritic tree in the sagittal plane, along the incoming axons from the auditory nuclei. As these afferents become functionally mature only after birth, this spatial remodeling of the dendrites seems closely related to functional maturation of secondary auditory axons. In the dorsomedial nucleus that receives fibers from the auditory cortices, the dendritic tree of DR cells also undergoes spatial reorientation. This is more evident in the horizontal plane and with respect to the incoming axons. Our results suggest that the characteristic orientation of the dendritic tree of cells observed in the inferior colliculus of the adult cat is established only after the first postnatal weeks. This orientation seems to result from an active process of remodeling concomitant with the functional maturation of afferents, a fact already established for various cell types in the nervous system.
通过对猫下丘两个中央核中树突树的网络分析，对树突的产后修饰进行了定量研究。该分析揭示了具有两种分支模式的细胞，提示了两种不同的生长模式。主要模式的特征是在随机节段上的二叉分支（DR细胞）。然而，纯侧支分支模式是某些细胞所特有的（CB细胞）。在成年猫和幼猫的下丘两个核中均发现了这两种分支模式，但这两种细胞类型的确切意义仍不清楚。小猫细胞的树突树与成年猫不同。此外，在我们研究的下丘两个功能不同的核中，修饰类型也不同。在接受来自脑干听觉核纤维的中央核中，DR细胞的树突树观察到最显著的修饰。有两个参数发生了改变：终末节段的平均数量和节段的平均总长度。这两个参数在矢状面增加而在额状面减少。这些修饰表明树突树在矢状面沿着来自听觉核的传入轴突重新定向。由于这些传入纤维仅在出生后才功能成熟，树突的这种空间重塑似乎与次级听觉轴突的功能成熟密切相关。在接受来自听觉皮层纤维的背内侧核中，DR细胞的树突树也经历空间重新定向。这在水平面和相对于传入轴突方面更为明显。我们的结果表明，成年猫下丘中观察到的细胞树突树的特征性定向仅在出生后的头几周后才建立。这种定向似乎是与传入纤维功能成熟相伴的主动重塑过程的结果，这一事实已在神经系统的各种细胞类型中得到证实。
