鸣禽栗鹀发声控制核团体积的侧别差异

为确定雄性鸣禽前脑发声控制核团体积的侧别差异,进而为一侧优势提供形态学依据,以东北常见鸣禽栗鹀(Emberiza rutila)成体为实验材料,采用冰冻连续冠状切片、焦油紫染色、图像分析等方法比较了雄性栗鹀左右侧发声控制核团的体积差异.结果表明:雄性栗鹀前脑发声控制核团的体积有明显的侧别差异,即左侧高级发声中枢(high vocal center,HVC)、古纹状体粗核(nucleus robust archistriatum,RA)、嗅叶X区(Xarea)的体积均比右侧的体积大,分别是右侧同名核团体积的1.14,1.30和1.1倍;而与鸣唱运动无关的核团,如位于延髓的螺旋内核(nucleus spitiformis medialis,SpM)则无明显的侧别差异.说明鸣禽鸣唱运动的高级控制中枢在形态学上存在明显的侧别差异.     

秋季黄胸巫鸟发声相关核团体积的雌雄差异

利用组织方法及微机处理技术测量了秋季成年雌、雄鸣禽黄胸巫鸟（ Ｅｍ ｂｅｒｉｚａ ａｕｒｅｏｌａ）发声相关核团 Ｈ Ｖｃ、 Ｒ Ａ、 Ｘ 区、ｎⅩⅡｔｓ 以及与发声无关的核团（ Ｓｐ Ｍ）的体积．结果表明：前脑的发声相关核团 Ｈ Ｖｃ、 Ｒ Ａ 及 Ｘ区具有明显的雌雄差异,而延髓的ｎⅩⅡｔｓ 以及与发声无关的核团 Ｓｐ Ｍ 则差异不明显     

栗鹀前脑发声控制核团的季节性差异

本实验测量了雄性成年栗鹀(Emberiza rutila)前脑及延髓的三个发声控制核团HVc、RA及nXIIts的体积。结果发现,前脑HVc用RA体积具有明显的季节性差异:春季明显大于秋季(P<0.01),而直接支配鸣肌的延髓NXIIts无季节性差异(P>0.05)。这表明,栗鹀鸣啭能力的春秋季差异与其前脑发声控制核团的春秋季体积变化有关。     

鸣禽鸟大脑发声中枢的性别差异和左侧优势

鸣禽雄、雌鸟的鸣转能力有明显差异。其原因是控制发声的大脑神经中枢HVC和RA在雄、雌之间有明显差异。雄性鸟的HVC和RA的体积及中枢内神经细胞体都比雌鸟大,其核内的神经细胞数量也比雌鸟多。这种差异又与性激素水平有关。雄激素可增加控制发声核内神经细胞蛋白质合成速度促进神经细胞发育。在鸣禽鸟高位发声中枢中有左侧优势现象即左侧HVC和RA都大于右侧HVC和RA。     

虎皮鹦鹉发声控制神经核团与鸣叫行为的性双态性研究

本文应用石蜡切片的方法，对成年虎皮鹦鹉的前脑发声控制神经核团：上纹状体腹侧尾核（Hyperstriatum ventrale pars Canssle,HVC)。古纹状体粗核（Nucleus robustus archistriaylis,RA)和嗅叶X区（Area X)进行了观察和比较；并采用计算机鸣声分析技术对虎皮鹦鹉的鸣声进行了分析。结果发现：雄鸟的三个发声控制神经核团体积明显大于雌鸟的三个发声控制神经核团体积。雄鸟的叫声明显比雌鸟的叫声复杂多变。这些结果提示虎皮鹦鹉的发声控制神经核团与鸣叫行为都存在着性双态性。     

燕雀发声核团体积与睾丸体积相关性的研究

利用组织方法及微机处理技术测量了成年鸣禽燕雀（ Ｆｒｉｎｇｉｌｌａ ｍ ｏｎｔｉｆｒｉｇｉｌｌａ）发声相关核团 Ｈ Ｖｃ、 Ｒ Ａ、 Ｘ 区与发声无关核团 Ｓｐ Ｍ （螺旋内核）及睾丸的体积。结果表明，发声相关核团 Ｈ Ｖｃ、 Ｒ Ａ、 Ｘ、区的体积与睾丸的体积变化具有明显的正相关，而发声无关核团 Ｓｐ Ｍ 与睾丸体积变化相关不明显     

白腰文鸟前脑发声控制核团的雌雄差异性研究

鸣禽的鸣叫行为在性别间存在着差异，这可能与其前脑内控制发声的神经核团有关．本实验采用石蜡切片、显微镜观察的方法，对雌雄白腰文鸟（onchura striata swinhoci）前脑发声控制核团的大小、神经元数量和密度进行了观察与对比．结果发现：雄鸟的三个发声控制核团均大于雌鸟；雄鸟核团中神经元的数量均超过雌鸟，而神经元的密度则小于雌鸟．以上结果差异均显著（P〈0．05），这说明白腰文鸟的发声控制核团存在着性双态性（Sexual dimorphism），     

声谱分析软件Wavesurfer在鸟类鸣声分析中的应用

由瑞典皇家技术学会（KTH）于2000年开发的Wavesurfer声谱分析软件能对声音数据进行观察、编辑、分类等多种分析．将其运用到鸟类鸣声分析中,更简单直观的获得鸟类鸣声的声学特性,为深入研究鸟类发声机理和发声行为提供技术支持．     

鸣禽栗鹀秋季发声相关核团体积的雌雄差异

实验利用组织学方法及微机处理技术测量了秋季成年雌雄鸣禽栗鹀(Emberiza ru-tile)的发声相关核团HVC、RA、X区、nXⅡts以及与发声无关核团SpM体积。结果表明,前脑的发声相关核团HV_c、RA及X区具有明显的雌雄差异,而延髓的mxⅡts以及发声无关核团SpM则雌雄差异不明显。     

秋季黄胸Wu发声相关核团体积的雌雄差异

利用组织方法及微机处理技术测量了秋季成年雌、雄鸣禽黄胸Ｗｕ（Ｅｍｂｅｒｉｚａ ａｕｒｅｏｌａ）发声相关核团ＨＶｃ、ＲＡ、Ｘ区、ｎｘⅡｔｓ以及与发声无关的核团（ＳｐＭ）的体积。结果表明：前脑的发声相关核团ＨＶｃ、ＲＡ及Ｘ区具有明显的雌雄差异,而延髓的ｎＸⅡｔｓ以及与发声无关的核团ＳｐＭ则差异不明显。     

The role of nonlinear dynamics of the syrinx in the vocalizations of a songbird

Birdsong is characterized by the modulation of sound properties over a wide image of timescales. Understanding the mechanisms by which the brain organizes this complex temporal behaviour is a central motivation in the study of the song control and learning system. Here we present evidence that, in addition to central neural control, a further level of temporal organization is provided by nonlinear oscillatory dynamics that are intrinsic to the avian vocal organ. A detailed temporal and spectral examination of song of the zebra finch (Taeniopygia guttata) reveals a class of rapid song modulations that are consistent with transitions in the dynamical state of the syrinx. Furthermore, in vitro experiments show that the syrinx can produce a sequence of oscillatory states that are both spectrally and temporally complex in response to the slow variation of respiratory or syringeal parameters. As a consequence, simple variations in a small number of neural signals can result in a complex acoustic sequence.     

Projection neurons within a vocal motor pathway are born during song learning in zebra finches

Many birds learn song during a restricted 'sensitive' period. Juveniles memorize a song model, and then learn the pattern of muscle contractions necessary to reproduce the song. Of the neural changes accompanying avian song learning, perhaps the most remarkable is the production of new neurons which are inserted into the hyperstriatum ventralis pars caudalis (HVc), a region critical for song production. We report here that in young male zebra finches many of the new neurons incorporated into the HVc innervate the robust nucleus of the archistriatum (RA) which projects to motor neurons controlling the vocal musculature. Furthermore, far fewer of these new neurons are incorporated into the HVc of either adult males that are beyond the sensitive learning period, or young females (who do not develop song). Thus, a major portion of the vocal motor pathway is actually created during song learning. This may enable early sensory experience and vocal practice to not only modify existing neuronal circuits, but also shape the insertion and initial synaptic contacts of neurons controlling adult song.     

鸣禽鸣啭控制核团内GABA能神经元的分布研究

应用免疫组化方法对鸣禽粟鹀(Emberiza rutila)鸣啭控制核团内GABA能神经元的分布进行了研究，在高级发声中枢(HVC，high vocal center)，古纹状体粗核(RA，the robust nucleus of the archistrialum)，X区(Arca X)3个前脑核团内有GABA样免疫反应出现．HVC和RA中GABA能神经元胞体大小存在性别和季节间的差异．结果提示GABA能神经元可能参与了鸣禽鸣啭的产生和鸣啭学习。     

去势对成年雄性斑胸草雀HVC神经元电生理特性的影响

鸣唱控制系统的高级发声中枢HVC（high vocal center）是发声运动通路和前端脑通路的始端，是发声行为的起始控制脑区，亦可接受听觉信号的输入及反馈，是鸣禽鸣唱调控最为重要的脑区.以往研究表明,雄激素及其代谢产物对鸣禽鸣唱控制有重要作用.去势显著改变鸣禽体内激素含量，进而影响鸣禽鸣曲稳定性，但其具体机制尚未阐明.我们运用全细胞膜片钳记录法，在离体细胞水平研究了去势引起的雄激素水平降低对HVC不同神经元电生理特性的影响.研究结果显示,去势组与对照组相比，投射神经元HVCRA，HVCX膜输入电阻减小，膜时间常数降低，动作电位后超极化幅值升高及达到峰值时间延长，表明雄激素可以提高两类投射神经元的兴奋性. 综上所述，雄激素可以一定程度上提高HVC神经元的兴奋性，雄激素可增强HVC对发声运动通路（vocal motor pathway,VMP)的控制，抑制前端脑通路(anterior forebrain pathway,AFP)来实现维持鸣曲的稳定.     

The role of sex steroids in the acquisition and production of birdsong

Male birdsong is generally regarded as a secondary sexual characteristic under the control of gonadal steroids. Song typically waxes and wanes with the seasonal cycle of testicular growth and regression and decreases after adult castration. Testosterone therapy reinstates song, induces it in females, augments it in intact males, and spring testosterone profiles correlate with seasonal song production. Thus, testosterone has been viewed as a major factor in song acquisition and production acting either directly, or after aromatization within the brain. We show here, however, that song learning and early phases of the development of singing both take place in castrated male birds with no significant levels of testosterone in their blood plasma. Testosterone seems to be required for song crystallization, however. Oestradiol was unexpectedly still present after castration, evidently from a non-testicular source, throughout the period of male song acquisition.     

Female visual displays affect the development of male song in the cowbird

The role of social stimulation in avian vocal learning is well documented. The separate contribution of social, as opposed to vocal, stimulation has been difficult to address, however, because in almost all cases both tutor and pupil sing. The opportunity to isolate such effects arose in cowbirds (Molothrus ater ater) after discovering that males housed with non-singing female cowbirds made vocal changes which related directly to the female preferences for native song. Here we report how females communicate with males about songs. We describe a visual display by females, a wing stroke, that is elicited by specific vocalizations. The songs that trigger wing strokes are in turn highly effective releasers of copulatory postures, and thus this previously unnoticed female display has biological significance. The data not only provide the first evidence of the tutorial role of male-female interactions during song ontogeny, they also clearly implicate visual stimulation in song learning, a process that has until now been assumed to be affected only by auditory information.     

两种鸣禽鸣啭控制核团体积的季节性变化

用Ｎｉｓｓｌ染色和ＨＥ染色,通过定量分析研究了鸣禽粟巫和燕雀鸣啭控制核团体积的季节性变化,同时对睾丸体积的季节性变化进行了观察,结果表明,鸣禽前脑三个主要鸣啭相关核团上纹状体腹侧尾核,古纹状体粗核,旁嗅叶的Ｘ区的体积存在显著的季节性差异。睾丸的体积和重量亦呈显著的季节性变化,这些结果揭示,鸣禽鸣啭能力的季节性变化是受鸣啭控制核团体积和睾酮水平季节性变化的影响。     

Performance variability enables adaptive plasticity of 'crystallized' adult birdsong

Significant trial-by-trial variation persists even in the most practiced skills. One prevalent view is that such variation is simply 'noise' that the nervous system is unable to control or that remains below threshold for behavioural relevance. An alternative hypothesis is that such variation enables trial-and-error learning, in which the motor system generates variation and differentially retains behaviours that give rise to better outcomes. Here we test the latter possibility for adult bengalese finch song. Adult birdsong is a complex, learned motor skill that is produced in a highly stereotyped fashion from one rendition to the next. Nevertheless, there is subtle trial-by-trial variation even in stable, 'crystallized' adult song. We used a computerized system to monitor small natural variations in the pitch of targeted song elements and deliver real-time auditory disruption to a subset of those variations. Birds rapidly shifted the pitch of their vocalizations in an adaptive fashion to avoid disruption. These vocal changes were precisely restricted to the targeted features of song. Hence, birds were able to learn effectively by associating small variations in their vocal behaviour with differential outcomes. Such a process could help to maintain stable, learned song despite changes to the vocal control system arising from ageing or injury. More generally, our results suggest that residual variability in well learned skills is not entirely noise but rather reflects meaningful motor exploration that can support continuous learning and optimization of performance.     

鸣禽鸣啭系统的可塑性及长时程增强研究

鸣禽的鸣唱控制系统已成为研究神经系统与学习、行为和发育相关的一个重要模型.鸣禽的鸣啭表现出一种复杂的学习过程.鸣禽学习鸣啭的过程可以分为两个阶段.在感觉学习期,幼鸟必须听到成鸟的鸣啭,并形成鸣啭模板记忆;在感觉运动学习期,鸣禽通过听觉反馈与模板匹配逐步建立稳定的鸣啭.该文对近年来鸣禽鸣啭学习过程中的新生神经元及长时程增强研究进展进行综述.     

Contributions of an avian basal ganglia-forebrain circuit to real-time modulation of song

Cortical-basal ganglia circuits have a critical role in motor control and motor learning. In songbirds, the anterior forebrain pathway (AFP) is a basal ganglia-forebrain circuit required for song learning and adult vocal plasticity but not for production of learned song. Here, we investigate functional contributions of this circuit to the control of song, a complex, learned motor skill. We test the hypothesis that neural activity in the AFP of adult birds can direct moment-by-moment changes in the primary motor areas responsible for generating song. We show that song-triggered microstimulation in the output nucleus of the AFP induces acute and specific changes in learned parameters of song. Moreover, under both natural and experimental conditions, variability in the pattern of AFP activity is associated with variability in song structure. Finally, lesions of the output nucleus of the AFP prevent naturally occurring modulation of song variability. These findings demonstrate a previously unappreciated capacity of the AFP to direct real-time changes in song. More generally, they suggest that frontal cortical and basal ganglia areas may contribute to motor learning by biasing motor output towards desired targets or by introducing stochastic variability required for reinforcement learning.