Ling C, Zuo M, Alvarez-Buylla A, Cheng M F
Department of Brain & Cognitive Science, Massachusetts Institute of Technology, Cambridge 02139, USA.
J Comp Neurol. 1997 Mar 10;379(2):300-12.
Studies in songbirds suggest that neurogenesis during the first few years of life is related to song learning. In this study, we examined whether postnatal neurogenesis occurs in a nonsongbird, the ring dove (Streptoplia risoria), and whether it persists to old age. Twenty-four hours after a single intramuscular injection of [3H]thymidine, labeled cells were present in the brains, particularly in the lateral wall of the lateral ventricle of juvenile (3-month and 8-month) and adult (1-year to 8-year) doves. Two months after multiple [3H]thymidine injections, there were fewer labeled cells in the ventricular zone (VZ), but many labeled cells with neuronal morphology in the parenchyma of the forebrain; labeled cells were confirmed as neurons by using neuron-specific markers, microtubule-associated protein-2 (MAP-2) and anti-neuronal nucleus (NeuN). In general, new neurons were distributed in the forebrain without clustering in any particular nucleus. During the first year of life, however, neostriatum caudale and hyperstriatum, the regions known to be essential for proper integration of sensory cues and reproductive behavior, contained more new neurons than any other brain regions. These neuronal additions showed an age-related decline; the first reduction coincided with the dove's attainment of adult physical size (about 3 months old) and the second occurred when the dove would normally attain reproductive fitness (about 1 year old). A low level of forebrain neurogenesis persisted up to 8 years of age (the oldest animals studied). These observations suggest that neurogenesis in adulthood is widespread among birds but that the biological significance of adult neurogenesis in the ring dove remains to be determined.
对鸣禽的研究表明，生命最初几年的神经发生与鸣叫学习有关。在本研究中，我们检测了非鸣禽环鸽（Streptoplia risoria）出生后是否会发生神经发生，以及这种现象是否会持续到老年。单次肌肉注射[3H]胸腺嘧啶核苷24小时后，大脑中出现了标记细胞，尤其是幼年（3个月和8个月）和成年（1岁至8岁）环鸽侧脑室的侧壁。多次注射[3H]胸腺嘧啶核苷两个月后，脑室区（VZ）的标记细胞减少，但前脑实质中有许多具有神经元形态的标记细胞；通过使用神经元特异性标记物微管相关蛋白2（MAP-2）和抗神经元核（NeuN），确认标记细胞为神经元。一般来说，新神经元分布在前脑，没有聚集在任何特定的核中。然而，在生命的第一年，已知对感觉线索和生殖行为的正确整合至关重要的尾侧新纹状体和上纹状体，比其他任何脑区含有更多的新神经元。这些新增的神经元数量呈现出与年龄相关的下降；第一次减少与鸽子达到成年体型（约3个月大）同时发生，第二次减少发生在鸽子通常达到生殖适能时（约1岁）。前脑神经发生的低水平一直持续到8岁（所研究的最年长动物）。这些观察结果表明，成年期神经发生在鸟类中很普遍，但环鸽成年期神经发生的生物学意义仍有待确定。
