Kirn J, O'Loughlin B, Kasparian S, Nottebohm F
Department of Biology, Wesleyan University, Middletown, CT 06459-0170.
Proc Natl Acad Sci U S A. 1994 Aug 16;91(17):7844-8. doi: 10.1073/pnas.91.17.7844.
Adult male canaries modify their song every year. Most of these changes occur during late summer and early fall, after the end of the breeding season, and in late winter, immediately before the onset of the next breeding season. The high vocal center (HVC) is an important nucleus in the brain pathway that controls this learned behavior. New neurons continue to be added to the HVC of adult male canaries, where they replace older neurons that have died. The present report describes the monthly incidence of cell death and neuronal addition in the HVC of such birds. Different groups of 1- to 2-year-old male canaries were treated with [3H]thymidine, a marker of cell birth, during each month of the year and killed 27 days later. The ratio of 3H-labeled neurons to all neurons in the HVC showed seasonal peaks and troughs. This ratio was highest in October and March. Peaks in the ratio of pycnotic (dying) HVC cells to all neurons in HVC preceded the peaks in the ratio of 3H-labeled neurons. We suggest that seasonal peaks in cell loss and neuronal recruitment in HVC are related to endocrine changes and that all three play a role in the seasonality of song modification.
成年雄性金丝雀每年都会改变它们的歌声。这些变化大多发生在夏末和秋初，即繁殖季节结束后，以及冬末，紧接着下一个繁殖季节开始之前。高级发声中枢（HVC）是大脑控制这种习得行为的神经通路中的一个重要核团。新的神经元会持续添加到成年雄性金丝雀的HVC中，在那里它们取代已经死亡的较老的神经元。本报告描述了此类鸟类HVC中细胞死亡和神经元添加的月度发生率。在一年中的每个月，对不同组的1至2岁雄性金丝雀注射[3H]胸腺嘧啶核苷（一种细胞诞生的标记物），并在27天后将它们处死。HVC中3H标记神经元与所有神经元的比例呈现出季节性的高峰和低谷。这个比例在10月和3月最高。HVC中固缩（即将死亡）细胞与所有神经元的比例高峰出现在3H标记神经元比例高峰之前。我们认为，HVC中细胞损失和神经元补充的季节性高峰与内分泌变化有关，并且这三者都在歌声改变的季节性中发挥作用。
