Nixdorf-Bergweiler B E, Wallhäusser-Franke E, DeVoogd T J
Department of Psychology, Cornell University, Ithaca, New York 14853, USA.
J Neurobiol. 1995 Jun;27(2):204-15. doi: 10.1002/neu.480270207.
We investigated the development of spiny neurons in the lateral magnocellular nucleus of the anterior neostriatum before, during, and after song learning in male zebra finches (Taeniopygia guttata). The frequency of dendritic spines, dendritic field size, and branching characteristics were quantified at different ages in Golgi-stained tissue using a three-dimensional computerized tracing system. During development, overall spine frequencies increase between 3 and 5 weeks and decrease thereafter. In particular, spine frequencies of middle segments decrease significantly by 14% between 5 and 7 weeks posthatching (p = 0.017). A further reduction of 48% occurs between 7 weeks and adulthood (p < 0.001), resulting in a spine reduction of 56% on middle segments between 35 days of age and adulthood. In addition to the reduction of spine frequencies, we find regressive events also on some of the neuronal parameters that we have quantified. In general, dendrites of adult animals terminate closer to the cell body than those of 7-, 5-, or 3-week-old birds. Whereas no changes in segment length of first- and second-order dendrites have been identified, third-order dendrites end 19% closer to the cell body in adults than in younger birds (p < 0.024). Second-order dendrites in adult animals branch less frequently than in 3-week-old animals (35%, p = 0.017). There is also a trend of a smaller number of tertiary branches in adulthood compared with 3-week-old birds (41%, p = 0.060). The morphological changes may be related to the function of this nucleus and the sensitive phase for song acquisition.
我们研究了雄性斑胸草雀（Taeniopygia guttata）在鸣叫学习之前、期间和之后，新纹状体前部外侧大细胞内核中棘状神经元的发育情况。使用三维计算机追踪系统，对不同年龄的高尔基染色组织中的树突棘频率、树突野大小和分支特征进行了量化。在发育过程中，总的棘频率在3至5周龄之间增加，之后下降。特别是，孵化后5至7周龄之间，中间节段的棘频率显著下降了14%（p = 0.017）。在7周龄至成年期之间，进一步下降了48%（p < 0.001），导致35日龄至成年期之间，中间节段的棘减少了56%。除了棘频率的降低，我们还发现我们量化的一些神经元参数也存在退行性变化。一般来说，成年动物的树突比7周龄、5周龄或3周龄鸟类的树突更靠近细胞体终止。虽然未发现一级和二级树突的节段长度有变化，但成年动物的三级树突比幼鸟的三级树突更靠近细胞体终止19%（p < 0.024）。成年动物的二级树突分支频率低于3周龄动物（35%，p = 0.017）。与3周龄鸟类相比，成年期的三级分支数量也有减少的趋势（41%，p = 0.060）。形态学变化可能与该核的功能以及鸣叫习得的敏感期有关。
