Motor Correlates of Song Production

描述(申请人提供)：鸣禽和鹦鹉是为数不多的人类语音动物模型之一，在这种模型中，可以通过实验研究产生复杂的、可学习的发声所涉及的基本生理和声学问题。然而，这些鸟类作为外周语音产生机制的模型的有用性受到以下事实的限制：尽管喉上声道在语音清晰度中起着突出的作用，但它是鸟类发声的最不为人所知的组成部分之一。这项研究旨在通过探讨脊髓上声道在鸟鸣中的作用和功能来填补这一空白。将通过实验测定禽类气管和口咽腔的声学特性。声道运动模式可能会在歌曲中通过改变声道的长度或形状来调节声音，从而改变其共鸣或滤波特性，这些模式将被监测和量化。将测量气管、喉咙、声门、舌头、喙和口咽运动的声学作用。可以跟踪发声的基频、改变宽带声音的共振峰结构或抑制选定的谐波分量的可调声道滤波器的位置和性质将被确定。将测试一个由鹦鹉产生的英语元音的两室模型。这些声道运动程序的个体发育与歌曲学习的其他方面有关，将在幼鸟身上进行调查。控制这些运动模式的运动神经元的位置及其运动前输入将被确定，将声道的运动控制与大脑中的歌曲控制电路联系起来的中央路径将被绘制出来，来自肺和空洞的反馈路径也将被绘制出来。听觉和体感反馈在提供可补偿不可预测的外周干扰的声道运动程序的闭环、实时调制方面的相对作用也将被研究。从这些实验中获得的知识将显著提高对歌曲产生的理解，并有助于研究同样适用于言语的发声控制的基本机制，包括口吃等重要言语流利性障碍的运动基础。

DESCRIPTION (provided by applicant): Songbirds and parrots are among the few animal models for human speech in which it is possible to experimentally study the basic physiological and acoustic problems involved in producing complex, learned vocalizations. The usefulness of these birds as a model for peripheral mechanisms of speech production is limited however by the fact that, although the supralaryngeal vocal tract plays a preeminent role in the articulation of speech, it is one of least well understood components of sound production in birds. This research aims to fill that gap by addressing the role and function of the suprasyringeal vocal tract in birdsong. The acoustic properties of the avian trachea and oropharyngeal cavity will be experimentally determined. Vocal tract motor patterns that may modulate sound by varying the length or shape of the vocal tract during song, thus altering its resonant or filter properties will be monitored and quantified. The acoustic role of tracheal, laryngeal, glottal, lingual, beak and oropharyngeal movements will be measured. The location and the nature of tunable vocal tract filters that may track the fundamental frequency of vocalizations, vary the formant structure of broadband sounds or suppress selected harmonic components will be determined. A two chamber model of English vowel production by parrots will be tested. The ontogenetic development of these vocal tract motor programs in relation to other aspects of song learning will be investigated in juvenile birds. The location of motor neurons controlling these motor patterns and their premotor inputs will be determined and the central pathways linking motor control of the vocal tract to the song control circuitry in the brain will be mapped, as will feedback pathways from the lungs and syrinx. The relative roles of auditory and somatosensory feedback in providing closed-loop, real-time modulation of vocal tract motor programs that may compensate for unpredictable peripheral perturbations will also be examined. The knowledge gained from these experiments will significantly improve the understanding of song production and the usefulness of birdsong for studying fundamental mechanisms of vocal control that also apply to speech, including the motor basis of important speech fluency disorders such as stuttering.