界面核和高级发声中枢与鸣禽鸣曲的学习和维持

Connections of NIf-HVC and Vocal Learning and Maintenance in Songbirds

鸣禽鸣唱和人类语言都是经过后天学习而获得的.幼鸟在学习鸣唱时先记住教习曲模板,再通过发声反馈比较自鸣曲和模板并调整发声输出,成年后同样需要听觉反馈来维持自鸣曲的特征和稳定.因此,鸣禽听觉系统和运动系统对刺激的感觉运动整合非常重要.近年研究发现,感觉期幼鸟编码并记忆模板的过程需要NIf-HVC投射的参与;这一突触联系与维持成年鸣禽可塑性鸣曲空间特征和鸣曲节律至关重要.其中,NMDAR、AchR和NE可能参与调节NIf-HVC突触的效能.HVC类似于人类的Broca's Area,而NIf类似于人类的Spt区,因此研究NIf-HVC突触在神经环路中的作用有助于揭示人类这2个脑区在语言形成中潜在的功能,有利于探索发声过程相关的感觉运动信息整合的机制.

Birdsong and human languages are both acquired by learning. During sensory period, templates are formed in the brain after juveniles heard tutor songs and stored in the related areas and in the motor-learning phase, juveniles compare their own songs to the templates and modify them to match the templates in their memories. When the songs are crystallized in the adult stage, auditory feedback is required to maintain the features and stabili- ty of their own songs. Hence, the sensory＇motor integration of auditory and motor systems is vitally important to the formation of templates and the maintenance of crystallized songs. In the recent years, it is found that NIf-HVC syn- apses are related with the formation of templates memory and the maintenance of spatial features of plastic songs in the juveniles while this projection is crucial for the grammar structure of crystallized songs in the Bengalese finches. In songbirds, HVC if homologous to human Broca＇s Area and NIf has many similarities with Area Spt in the human speech processing circuit. Therefore the research on the function of NIf-HVC synapses in the speech circuit is not only helpful for the study of Area Broca and Spt of human but also advantageous for exploring the mechanism con- cerning sense and motion information integration involved in vocal learning.