Villacorta Virgilio M, Perkell Joseph S, Guenther Frank H
Speech Communication Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Room 36-591, 50 Vassar Street, Cambridge, Massachusetts 02139, USA.
J Acoust Soc Am. 2007 Oct;122(4):2306-19. doi: 10.1121/1.2773966.
The role of auditory feedback in speech motor control was explored in three related experiments. Experiment 1 investigated auditory sensorimotor adaptation: the process by which speakers alter their speech production to compensate for perturbations of auditory feedback. When the first formant frequency (F1) was shifted in the feedback heard by subjects as they produced vowels in consonant-vowel-consonant (CVC) words, the subjects' vowels demonstrated compensatory formant shifts that were maintained when auditory feedback was subsequently masked by noise-evidence of adaptation. Experiment 2 investigated auditory discrimination of synthetic vowel stimuli differing in F1 frequency, using the same subjects. Those with more acute F1 discrimination had compensated more to F1 perturbation. Experiment 3 consisted of simulations with the directions into velocities of articulators model of speech motor planning, which showed that the model can account for key aspects of compensation. In the model, movement goals for vowels are regions in auditory space; perturbation of auditory feedback invokes auditory feedback control mechanisms that correct for the perturbation, which in turn causes updating of feedforward commands to incorporate these corrections. The relation between speaker acuity and amount of compensation to auditory perturbation is mediated by the size of speakers' auditory goal regions, with more acute speakers having smaller goal regions.
在三个相关实验中探究了听觉反馈在言语运动控制中的作用。实验1研究了听觉感觉运动适应：即说话者改变其言语产生以补偿听觉反馈扰动的过程。当在辅音-元音-辅音（CVC）单词中产生元音时，受试者听到的反馈中第一共振峰频率（F1）发生偏移，受试者的元音表现出补偿性共振峰偏移，当随后听觉反馈被噪声掩盖时这种偏移仍会持续——这是适应的证据。实验2使用相同的受试者，研究了对F1频率不同的合成元音刺激的听觉辨别。那些F1辨别更敏锐的人对F1扰动的补偿更多。实验3包括使用言语运动计划的发音器模型从方向到速度的模拟，结果表明该模型可以解释补偿的关键方面。在该模型中，元音的运动目标是听觉空间中的区域；听觉反馈的扰动会调用听觉反馈控制机制来校正该扰动，这反过来又会导致前馈命令更新以纳入这些校正。说话者的敏锐度与对听觉扰动的补偿量之间的关系由说话者听觉目标区域的大小介导，更敏锐的说话者具有更小的目标区域。
