白腰文鸟发声相关核团体积在发育中的变化及神经机制

首先研究了5-120日龄雌雄白腰文鸟（Lonchura striata swinhoei)4个主要发声核团（RA,LMAN,AreaX和HVC）的体积变化,再通过神经示踪技术研究这些核团与其他核团神经联系的建立时间,以了解发声核团发育及性别分化的神经机制,结果表明：（1）雌雄RA体积均在20,30日龄前后表现出急剧的变化和雌雄差异;雌雄RA在15和25日龄分别接受LMAN和HVC的神经支配,（2）雌雄LMAN体积分别在20,30日龄前先增长,之后均缩小,雌雄LMAN的神经元大小均在15和20日龄间急剧增长,但在该时段之后,不再发生明显变化,雌雄LMAN均在15日龄接受RA的神经支配。（3）AreaX核体积,神经元大小最明显的变化位于20-25日龄间;雌雄AreaX核均在15日龄时接受HVC的神经支配,（4）AreaX核体积,神经元大小最明显的变化位于20-25日龄间;雌雄AreaX核均在15日龄时接受HVC的神经支配,（4）雌雄HVC体积变化的最大值在20和30日龄前后,雄乌HVC的神经元大小在20,30日龄前后,雌鸟在15-20日龄发生较大的变化,其余组间变化小或不明显,雌雄HVC分别在15,25日龄同AreaX核,RA建立神经联系,因此,4个发声核团组织学的明显变化与核团间神经联系的建立相关,说明发声核团间的神经联系可能影响和决定了核团体积在发育中的变化。     

鸣禽白腰文鸟前脑古纹状体粗核性双态发育的神经机制

对鸣禽白腰文鸟 (Lonchurastriata)发声控制核团古纹状体粗核 (robustnucleusofarchistriatum ,RA)的性双态分化过程进行了组织学研究 ,并应用双向神经示踪剂 (biotinylateddextranamine ,BDA) ,追踪新纹状体外侧巨细胞核 (lateralnucleusmagnocellularisofanteriorneostriatum ,LMAN)和高级发声中枢 (highvocalcenter,HVC)与RA建立纤维联系的时间和过程。结果发现 :5～ 3 5日龄段为雌雄RA体积、神经元大小和神经元密度变化最集中的时间。在该时段内 ,RA体积、神经元大小均增加 3～ 4倍 ,而RA神经元密度减少约 4倍。这些变化在雌雄间无显著差异 (P >0 0 5 ,非配对 ,双尾t 检验 ) ,但与RA同LMAN、HVC建立神经联系的时间一致。RA同LMAN、HVC建立联系的时间分别为 5～ 15和 15～ 3 5日龄。 4 5日龄后 ,RA体积大小在雌、雄间出现显著差别 (P <0 0 5 )。 4 5～ 60日龄为雌鸟神经元凋亡数量最多时期 ,4 5和 60日龄神经元凋亡数分别为 19 4± 8 0和 17 9± 8 2 (× 10 3/mm3)。结果提示 :4 5日龄后雌雄鸟RA体积和神经元凋亡的变化可能是鸣禽发声核团性双态产生的主要原因。     

血清性激素在白腰文鸟前脑发声控制核团神经元早期性双态分化中的作用

本文究了雌、雄白腰文鸟(Lonchura striata swinhoei)不同发育时期前脑四个控制发声重要核团古纹状体栎核(RA)、新纹状体前部巨细胞核外侧部(LMAN)、X区(Area X)和高级发声中枢(HVC)中神经元数量、体积和体内雌二醇(E2)和睾酮(T)浓度的变化,以揭示性激素对鸣禽发声核团性双态性分化的影响。结果发现：(1)HVC、LMAN和X区在发育早期神经元数量和体积均呈显著性双态性差异,而RA神经元直至30日龄(P30)后才显示出明显性别差异(P＜0．05);(2)除RA外,HVC、LMAN和X区神经元体积的显著性双态性差异均发生在P20左右,P20后雌、雄核团内的神经元体积仅有较小范围的波动;(3)RA和LMAN神经元数量随年龄增长而逐渐减少;雌、雄鸟HVC和雄鸟X区的神经元数量在P20—30间均增长,雄鸟HVC的增长幅度显著大于雌鸟。P30后HVC和X区的神经元数量不再增加,开始小幅度减少;(4)四个发声核团的神经元数量和体积在P5-120期间均出现1—2个急剧变化期,此变化期与体内雌激素水平开始出现显著性差异的临界期及核团间神经联系开始建立的时期相对应;(5)雌、雄鸟血清中E2的水平在核团发育初期(P5)差异显著,雌鸟为雄鸟的7．45倍,P5后则呈相反方向变化趋势,在P15时雄鸟中的E2水平反超过雌鸟,差异显著(P＜0．05)。睾酮仅在发育P50后的雄鸟体内被检测出,雌鸟中始终未能检测出T的存在。结果提示：雌、雄白腰文鸟发育早期体内E2浓度的变化启动了HVC、LMAN和X区早期神经元性双态性的分化和持续发育;睾酮对雌、雄鸣禽发声控制核团中早期神经元的性双态性分化作用较小[动物学报49(3)：353—361,2003]。     

10种鸣禽控制鸣啭神经核团大小与鸣唱复杂性的相关性

为进一步揭示鸣禽鸣唱行为的神经生物学机制 ,本实验先对 8个科 10种鸣禽的鸣唱行为进行了观察和录音 ,并借助声谱软件分析了每种鸣禽的鸣唱复杂性。鸣唱语句复杂性的评价指标包括 :短语总数、每个短语中所含的平均音节数及音节种类数、所有短语的总音节数及音节种类数、最长短语的音节数及音节种类数。然后 ,测定了前脑三个鸣啭学习控制核团和一个与发声无关的视觉参考核团体积 ,分析了鸣唱语句复杂性和这些核团大小间的相关关系。结果表明 :1)HVC和HVC/Rt与 7种鸣唱语句复杂性指标无关 ;RA和RA/Rt与总音节种类数相关 ;AreaX与总音节数及音节种类数相关 ;2 )HVC/RA和HVC/X比值与多个鸣唱语句复杂性指标相关。结果提示 :鸣禽鸣唱复杂性不同特征可能受不同神经控制     

鸣禽栗鹀前脑古纹状体粗核及其周区的神经联系

鸣禽的发声及其学习过程涉及前脑不同部位的几个核团,其中高级发声中枢(high vocal center,HVC)是发声控制的主导核团(Nottebohm等,1976);古纹状体粗核(robust nucleus of archistriatalis,RA)是前脑多种信息的会聚点(Wild,1994),并在呼吸与发声协调等方面有相当重要的作用(Vicario,1991).国外曾对金丝雀、斑胸草雀RA的纤维联系有过系统的研究(Nottebohm等,1982;Wild,1993),国内张信文等(1994)也曾对黄雀RA的纤维联系进行过报道.     

不同生长发育期的虎皮鹦鹉发声行为与发声控制神经核团的研究

鸟类的鸣叫依赖于发育完善的鸣管并接受各级发声中枢组成的机能控制系统的调控,善鸣唱的鸟类前脑控制发声的神经核团发达.用石蜡切片法和生物信号采集处理系统对不同生长发育期的虎皮鹦鹉的发声控制神经核团的体积和声音进行了比较性研究.结果发现:(1)随着虎皮鹦鹉的成长,核团体积逐渐增大,核团轮廓逐渐清晰,而且雄鸟的核团明显大于雌鸟;(2)在鸟类成长的过程中,鸟的叫声越来越复杂,幅度越来越高,雄鸟的叫声比雌鸟更复杂,雌鸟的叫声比雄鸟的叫声幅度更高;(3)鸟类鸣叫的复杂程度和发声控制神经核团的体积呈相关性.     

白腰文鸟发声行为的性别差异及其机制

通过声谱分析,研究了５－１２０日龄雌、雄白腰文鸟（Lonchura striata swinhoei)的声谱变化,及该时段３个主要发声控制核团）ＨＶＣ、ＲＡ、Ａrea X)体积、睾丸（睾酮）的相应改变。结果如下：①４５日龄以前,雌雄鸟只能发出简单鸣叫（call),鸣声基本不会鸣唱。②雄性ＨＶＣ,ＲＡ,ＡreaX体积均比雌性大２－６部。３个核团的大小发育不完全一致。各核团的快速生长期与鸣唱学习的主要时段（６０－１２０日龄）不同步,说明核团的个体发育可能不完全受发声行为的影响。③睾丸的充分发育（１２０日龄后）及血液中具有较高的睾酮水平是雄鸟发出成熟鸣唱语句的重要条件。     

鸣禽栗鹀前脑鸣啭控制核团与性腺体积的相关性 *

用组织学技术和微机处理方法研究了春秋两季雄性成年鸣禽栗鹂前脑鸣啭相关核团体积与性腺体积之间的相关性。结果表明,与鸣啭控制直接相关的核团HVC、RA以及在鸣啭学习中具有重要作用的X区体积均随睾丸体积变化而发生显著的正相关性变化,而与发声无关的对照核团则没有这种相关性。     

白腰文鸟嗅叶X区的神经回路与P物质的免疫组化定位

用双向神经示踪剂生物素结合的葡聚糖胺和SP-免疫组织化学方法研究白腰文鸟发声学习中枢嗅叶X区的神经投射和P物质在发声中枢及相关核团内的分布。结果表明：X区接受发声与听觉整合中枢上纹状体腹侧尾核(HVC)以及中脑AVT的传入投射,由X区发出的神经纤维投射到丘脑外侧核内侧部(DLM)。在HVC、DLM、新纹状体前部巨细胞核和发声控制中枢古纹状极核内有许多的SP-免疫阳性神经细胞,在X区、中脑背内侧核和延髓舌下神经核等有大量的SP-免疫阳性神经纤维或终末等。提示P物质可能在发声中枢内起重要的生理作用。     

鸣禽锡嘴雀(Coccothraustes coccothraustes)发声中枢的定位研究

用常规组织学,HRP 逆行示踪,电生理等方法确定了鸣禽锡嘴雀控制发声的神经核团及这些核团的定位坐标值。锡嘴雀控制发声的神经通路由四级神经核团组成。位于端脑上纹状体腹侧的尾部区域(HVc)是控制鸣禽发声的高位中枢,它发出的神经纤维投射到端脑原纹状体腹内侧的粗核(RA),由 RA 又发出两束纤维,分別投射到中脑丘间核(ICo)和延脑的中间核(IM)。左右侧发声控制神经通路并非严格单侧性,每侧气管鸣管肌群分別受双侧发声中枢的交叉控制。中脑 ICo 在控制发声行为中具有相对独立性。各级发声核团的定位坐标值为,HVc∶p1.3,L/R2.4,H0.8;RA∶1.4,L/R3.2,H6.0;ICo∶p0.3,L/R2.6,H8.5:IM∶P3.1,L/R1.0,H∶7.8。     

Testosterone-induced changes in adult canary brain are reversible

Brain nuclei that control song are larger in male canaries, which sing, than in females, which sing rarely or not at all. Treatment of adult female canaries with testosterone (T) induces song production and causes song-control nuclei to grow, approaching the volumes observed in males. For example, the higher vocal center (HVC) of adult females approximately doubles in size by 1 month following the onset of T treatment. Male HVC projects to a second telencephalic nucleus, RA (the robust nucleus of the archistriatum), which projects in turn to the vocal motor neurons. Whether HVC makes a similar connection in female canaries is not known, although HVC and RA are not functionally connected in female zebra finches, a species in which testosterone does not induce neural or behavioral changes in the adult song system. This experiment investigated whether HVC makes an efferent projection to RA in normal adult female canaries, or if T is necessary to induce the growth of this connection. In addition, we examined whether T-induced changes in adult female canary brain are reversible. Adult female canaries received systemic T implants that were removed after 4 weeks; these birds were killed 4 weeks after T removal (Testosterone-Removal, T-R). Separate groups of control birds received either (a) T implants for 4 weeks which were not removed (Testosterone-Control, T-C) or (b) empty implants (Untreated Control, øO-C). Crystals of the fluorescent tracer DiI were placed in the song-control nucleus HVC in order to anterogradely label both efferent targets of HVC, RA and Area X. Projections from HVC to RA and Area X were present in all treatment groups including untreated controls, and did not appear to differ either qualitatively or quantitatively. Thus, formation of efferent connections from HVC may be prerequisite to hormone-induced expression of song behavior in adult songbirds. The volumes of RA and Area X were measured using the distribution of anterograde label as well as their appearance in Nissl-stained tissue. RA was larger in T-treated control birds than in untreated controls. Experimental birds in which T was given and then removed (T-R) had RA volumes closer in size to untreated controls (ø-C). Because the volume of RA in T-treated controls (T-C) was larger than that of birds that did not receive T (ø-C), we conclude that the volume of RA increased in both T-C and T-R birds but regressed upon removal of T in T-R birds. Surprisingly, the volume of Area X did not increase in T-treated birds. Birds in this study were maintained on short days, suggesting that T-induced growth of Area X reported previously may have resulted from an interaction between T and another seasonal or photoperiodic factor induced by exposure to long daylengths. © 1993 John Wiley & Sons, Inc.     

Learning-Related Neuronal Activation in the Zebra Finch Song System Nucleus HVC in Response to the Bird's Own Song

Like many other songbird species, male zebra finches learn their song from a tutor early in life. Song learning in birds has strong parallels with speech acquisition in human infants at both the behavioral and neural levels. Forebrain nuclei in the 'song system' are important for the sensorimotor acquisition and production of song, while caudomedial pallial brain regions outside the song system are thought to contain the neural substrate of tutor song memory. Here, we exposed three groups of adult zebra finch males to either tutor song, to their own song, or to novel conspecific song. Expression of the immediate early gene protein product Zenk was measured in the song system nuclei HVC, robust nucleus of the arcopallium (RA) and Area X. There were no significant differences in overall Zenk expression between the three groups. However, Zenk expression in the HVC was significantly positively correlated with the strength of song learning only in the group that was exposed to the bird's own song, not in the other two groups. These results suggest that the song system nucleus HVC may contain a neural representation of a memory of the bird's own song. Such a representation may be formed during juvenile song learning and guide the bird's vocal output.     

Sex differences in the telencephalic song control circuitry in Bengalese finches (Lonchura striata var. domestica)

Bengalese finches, Lonchura striata, are extremely sexually dimorphic in their singing behavior; males sing complex songs, whereas females do not sing at all. This study describes the developmental differentiation of the brain song system in Bengalese finches. Nissl staining was used to measure the volumes of four telencephalic song nuclei: Area X, HVC, the robust nucleus of the arcopallium (RA), and the lateral portion of the magnocellular nucleus of the anterior nidopallium (LMAN). In juveniles (circa 35 days old), Area X and the HVC were well developed in males, while they were absent or not discernable in females. The RA was much larger in males but barely discernable in females. In males, the volumes of Area X and the RA increased further into adulthood, but that of the HVC remained unchanged. The LMAN volume was greater in juveniles than in adults, and there was no difference in the LMAN volume between the sexes. The overall tendency was similar to that described in zebra finches, except for the volume of the RA, where the degree of sexual dimorphism is larger and the timing of differentiation occurs earlier in Bengalese finches. Motor learning of the song continues until day 90 in zebra finches, but up to day 120 in Bengalese finches. Earlier neural differentiation and a longer learning period in Bengalese finches compared with zebra finches may be related to the more elaborate song structures of Bengalese finches.     

Comparative analyses of song complexity and song-control nuclei in fourteen oscine species

Most studies on the relationship between measures of song behavior and the sizes of song control nuclei have focused on one or two oscine species, and often show inconsistent results. To address this issue, we first measured four variables for song complexity, i.e., song repertoire size, syllable repertoire size, the mean number of syllables per phrase (MNS) and the number of syllables in the longest phrase (NSLP), and the sizes of three song control nuclei, i.e., HVC, RA (the robust nucleus of the arcopallium), and Area X in 14 oscine species from eight families. To tackle the problem of statistical non-independence that probably existed among the closely related species, we reconstructed the phylogeny of the species studied using mitochondrial cytochrome b DNA sequences from GenBank. By using the methods adopted in most previous reports, we tested the relationship between song complexity and the sizes of the song control nuclei. We found that: 1) the absolute sizes of RA and Area X, but not of HVC, were positively correlated to the three measures of song complexity, but that only the residual size of RA in regard to telencephalon size was significantly correlated to the song measures; 2) independent contrasts analysis showed RA and Area X to be significantly associated with NSLP. Our results indicated that the relationship between song behavior and its neural structures varied among song nuclei, suggesting that each song control nucleus may play a different role in song behavior.     

10种鸣禽鸣唱复杂性与发声核团体积的聚类分析

选用捕自野外和人工繁殖的10种雄性成鸟(一年龄以上)作为实验材料。当鸟适应环境后录音,用VS-99语音工作站软件进行声谱分析。鸣唱的复杂性采用语句短语总数、短语的音节数之和、短语的音节种类数之和、每个短语中所含的平均音节数、每个短语中所含的平均音节种类数、每种鸣禽最长短语的音节数和最长短语的音节种类数7项指标表示。然后测定前脑的上纹状体腹侧尾端(HVC)、古纹状体粗核(RA)以及嗅叶的X核(Areax)3个主要鸣唱控制核团的体积。最后分别对10种鸣禽3个发声控制核团体积和鸣唱复杂性的7项指标进行聚类分析。10种鸣禽的7项指标值相差较大,即使同一科也如此。蒙古百灵的3种核团体积比值均最大,其次是金丝雀和黄喉鹉。10种鸣禽鸣唱语句复杂性的7个指标和3种核团体积聚类分析树形图显示的结果各不相同;仅RA和Areax核团体积的树形图显示蒙古百灵远离其他9种鸣禽,与现代分类学和DNA分析得到的进化树一致。     

Differential estrogen accumulation among populations of projection neurons in the higher vocal center of male canaries

The higher vocal center (HVC) of adult male canries undergoes a seasonal change in volume that corresponds to seasonal modifications of vocal behavior: HVC is large when birds produce stereotyped song (spring) and is small when birds produce plastic song and add new song syllables into their vocal repertoires (fall). We reported previously that systemic exposure to testosterone (T) produces an increase in the volume of HVC similar to that observed with long-day photoperiods. T-induced growth of HVC occured regardless of wheter the borders of HVC were defined by Nissl-staining, the distribution of androgen-concentrating cells, or the distribution of projection neurons [separate neuronal populations within HVC project to the robust nucleus of the archistriatum (RA) and to Area X of the avian striatum (X)]. In the present study we used steroid autoradiography to determine whether T can influence the distribution of HVC cells that bind estrogen, and we combined estrogen autoradiography with retrograde labeling to determine whether HVC neurons that project to RA versus X differ in their ability to accumulate estrogen. Results showed that T increased the volume of Nissl-defined HVC and although HVC contained a low density of estrogen-concentrating cells, T increased the spatial distribution of these cells to match the Nissl borders of HVC. We also identified a region containing a high density of estrogenconcentrating cells located medial to HVC [we call this region paraHVC (pHVC)], and T also increased the volume of pHVC. pHVC also contained numerous X-projecting neurons, but few if any RA-projecting neurons. Double-labeling analysis revealed the RA-projecting neurons did not accumulate estrogen, a small percentage of X-projecting neurons in HVC accumulated estrogen, and the majority of X-projecting neurons in pHVC showed heavy accumulation of estrogen. The data reported here and in our previous article suggest distinct roles for gonadal steroids within the HVC-pHVC complex: estrogens are concentrated by neurons that project to a striatal region that influences vocal production during song learning (X), whereas androgens are concentrated primarily by neurons that project to a motor region that is involved in vocal production during both song learning and the recitation of already-learned song (RA). © 1995 John Wiley & Sons, Inc.