白腰文鸟发声行为的神经发育

本文研究了 5～ 15 0日龄雄性白腰文鸟 (Lonchurastriataswinhoei)不同年龄段的声谱变化以及这种变化的神经调制机制。结果如下 :(1)HVC、RA和AreaX三个发声核团的神经联系基本接近成年鸟的水平后 ,幼鸟才开始学习鸣叫 (约 45日龄 ) ;(2 )HVC、RA和AreaX达到成年核团体积时 (约 80日龄 ) ,幼鸟才具有成年雄鸟的鸣叫模式 ;(3)发声控制核团的发育与核团间的神经支配有关 ,而基本不受鸣唱行为的影响 ,HVC、RA和AreaX的最快增长时间段各不相同 ,三个核团随年龄增长而呈现体积增长的显著变化 (one wayANOVA ,P <0 0 5 ) ,但各核团在任意两个时间段的体积差异并不都显著。结果提示 :发声行为产生的时间和发展与发声控制核团的发育、核团间的神经联系有关 ,最终的体积发育程度受内在遗传力的作用 ,同时可能还受神经核团建立正常神经联系时间的影响

NEURAL DEVELOPMENT OF VOCAL BEHAVIOR IN STRIATED MANNIKIN (LONCHURA STRIATA SWINHOEI)

Songbird has specialized areas in the brain that are necessary for the generation of song.In striated mannikin(Lonchura striata swinhoei), the discrete nuclei, robust nucleus of the archistriatum(RA), high vocal center(HVC), lateral magnocellular nucleus of the anterior neostriatum(LMAN) and Area X, make up one part of the song system that is thought to be important for such early song acquisition.However, the relation between development of song nuclei and behavior of song learning has not been well documented.The male striated mannikin, aged from 5 days (P5) to 150 days (P150) post-hatching were studied in this experiment.We examined the development of control vocal nuclei and behavior of learned song by analyzing the spectrogram structures.The results were as follows: (1)After neural connections by day 45 were established among the HVC, RA and Area X, juvenile striated mannikin began to learn singing;(2)The striated mannikin could not get the adult song structures prior to day 80 until the volumes of HVC,RA and Area X respectively reached their adult size;(3)The volumetric growth of three song nuclei were not correlated with the process of song learning, but seem to be affected by the establishment of neural connections among the three related song nuclei.The RA, HVC, or Area X volumes increased most rapidly at different stage.Multivariate analysis of variance indicated the effect on age from P5 to P150 (P<0.05) for the RA, HVC or Area X (one-way ANOVA).However, the difference of nuclei volumes between any two groups at different stages was not always significant.The results suggested that the onset and development of song behavior of striated mannikin depend on the normal development in nuclei and the establishment of the neural connections within song control nuclei.The final volumes of the adult song nuclei may be decided mainly by inheritance and affected by the formation of normal projections within song nuclei, but not by the song behaviors.