雄激素调节前脑RA突触可塑性对成年鸣禽鸣曲稳定性的影响

Androgens, especially testosterone, are closely related to the maintenance of the song stability of adult songbirds. The robust nucleus of the arcopallium (RA), which is a vital target of androgens, receives the projection from the nucleus HVC in vocal motor pathway (VMP) and the nucleus LMAN in anterior forebrain pathway (AFP) respectively，and involves in sensorimotor integration. The RA plays a key role in controlling the vocal output and maintaining the song stability. Androgens may cause the song change by modulating the morphological and functional changes of RA. Based on our previous studies, we are going to investigate the mechanism of androgens between the synaptic plasticity in RA and the song stability using two kinds of songbirds, canary and zebra finch, in which the former is seasonal breeding and the latter is non-seasonal breeding songbird. Combining the techniques of changing photoperiod, castration and implanting testosterone，we attempt to compare the differences between two species of songbirds in the neural structures,electrophysiological properties and synaptic functions. This research will provide scientific evidences for revealing the effects of androgens on the neural mechanisms of changing of vocal behavior and RA synaptic plasticity and provide references for the research on the learning of human language in the perspective of comparative physiology.

雄激素尤其是睾酮在成年鸣禽鸣唱稳定性方面发挥重要作用。前脑弓状皮质栎核（RA）分别接受来自发声运动通路HVC和前端脑通路LMAN的输入，不仅参与感觉运动整合，也是雄激素作用的重要靶点，在发声运动和鸣曲稳定方面扮演关键角色。雄激素可通过调节RA形态和功能引起鸣唱行为的改变。本课题在前期工作基础上，以两种不同繁殖类型成年雄性鸣禽-金丝雀和斑胸草雀为实验材料，通过改变光周期、去势和埋植睾酮，从RA神经元形态结构、神经元电生理特性和突触功能等方面探究雄激素对RA突触可塑性调节的相关机制及对鸣曲稳定性的影响，以期为深入阐明成年鸣禽鸣唱维持的神经机制提供科学依据，并从比较生理学角度为人类语言学习研究提供借鉴。

雄激素尤其是睾酮在成年鸣禽鸣唱稳定性方面发挥重要作用。前脑弓状皮质栎核（RA）分别接受来自发声运动通路HVC和前端脑通路LMAN的输入，不仅参与感觉运动整合，也是雄激素作用的重要靶点，在发声运动和鸣曲稳定方面扮演关键角色。雄激素可通过调节RA形态和功能引起鸣唱行为的改变。本课题在前期工作基础上，以成年雄性斑胸草雀为实验材料，通过去势和埋植睾酮，从RA神经元形态结构、神经元电生理特性和突触功能等方面探究雄激素对RA突触可塑性调节的相关机制及对鸣曲稳定性的影响，以期为深入阐明成年鸣禽鸣唱维持的神经机制提供科学依据，并从比较生理学角度为人类语言学习研究提供借鉴。.我们分别观察了去势和埋置睾酮对鸣曲的影响，对RA投射神经元电生理特性的影响以及HVC，LMAN，X等核团形态学及功能变化。血浆睾酮水平去势后明显降低，并引起前脑鸣唱核团NR2B表达增加。鸣曲熵值增加，相似度下降。去势鸣曲不稳定性可被损毁LMAN逆转鸣曲的变化表明，LMAN对睾酮调节鸣曲变化至关重要。雄激素可能通过影响HVC-RA通路的LTD水平来维持鸣曲稳定性，并对该通路的短时程突触可塑性有一定的调节作用。使用全细胞膜片钳记录了RA神经元自发兴奋性突触后电流和微小兴奋性突触后电流，发现其频率幅值存在性别差异，且去势后频率有改变，幅值无改变。也记录了RA自发放和诱发放，膜特性和后超级化等电生理指标，表明去势可降低鸣曲稳定性和RA神经元的兴奋性。