Neural Control of Vocal Production in Tone-Deafness

描述（由申请人提供）：虽然我们都知道一个或多个人谁不能唱歌的调子，这种疾病的神经相关性和它可能揭示的沟通控制模型仍然难以捉摸。除了不能唱准调子外，音盲的一个特征性标志是心理物理音高辨别阈值异常大，超过1000。无法区分细微的音高差异可能是这种疾病的附带现象，也可能与假定的运动障碍有关，这种运动障碍是音高产生障碍的基础。来自形态测量、功能成像和事件相关电位（ERP）研究的先导和先前数据指向参与听觉反馈控制和声音-运动映射的区域的功能和结构异常，而不是初级听觉皮层的功能障碍。在考虑到无法唱歌可能是反映的问题，包括前馈和反馈控制机制的运动整合，目前的理论框架允许我们推广现有的模型的语音感知和生产领域的歌唱作为一个实例的“吟诵语音”。我们的一般假设是，音聋是一个涉及听觉反馈和音高产生前馈控制的大脑区域网络功能障碍的结果。我们计划通过首先确定音调聋的行为和神经基础来验证这一假设。通过结合音高产生的神经影像学和心理物理学实验，包括使用音高移位听觉反馈，我们将测试负责听觉反馈控制和声音-运动映射的神经机制以及这两个系统的相互作用（目的1）。然后，我们将通过使用一种新的非侵入性脑刺激方法（经颅直流电刺激- TDCS）创建暂时的区域功能障碍来反向工程感知通路（目标2）。根据试点音高生产的结果，大脑刺激可以暂时诱导音聋正常人，从而使我们能够评估我们的区域假设使用心理物理措施，已在实验中评估从第一个目标。检查音盲的神经相关性，并在正常受试者中创建一个音盲等效物，将为正常和障碍言语以及非言语交流中大脑中听觉和运动系统的相互作用提供新的见解。

DESCRIPTION (provided by applicant): Although we all know one or more individuals who can't sing in tune, the neural correlates of this disorder and what it might reveal about models of communication control remain elusive. In addition to an inability to sing in tune, one characteristic marker of tone-deafness is an abnormally large psychophysical pitch discrimination threshold of more than one semitone. The inability to discriminate fine pitch differences may be an epiphenomenon of the disorder, or it could be related to the presumed auditory-motor dysfunction that underlies disabled production of vocal pitch. Pilot and previous data from morphometric, functional imaging, and Event- Related Potential (ERP) studies point towards functional and structural abnormalities in regions involved in auditory feedback control and sound-motor mapping, rather than dysfunctions in primary auditory cortex. In considering that the inability to sing might be reflective of problems in auditory-motor integration including feedforward and feedback control mechanisms, the present theoretical framework allows us to generalize existing models of speech perception and production to the domain of singing as an instance of "intoned-speech". Our general hypothesis is that tone-deafness is a result of dysfunction in a network of brain regions involved in auditory feedback and feedforward control of vocal pitch production. We plan to test this hypothesis by first identifying the behavioral and neural substrates of tone-deafness. By combining neuroimaging and psychophysical experiments of pitch production, including the use of pitch- shifted auditory feedback, we will test the neural mechanisms responsible for auditory feedback control and sound-motor mapping as well as the interaction of these two systems (Aim 1). We will then reverse-engineer the perceptuomotor pathway by creating temporary regional dysfunctions using a new method of non-invasive brain stimulation (transcranial direct current stimulation - TDCS) (Aim 2). Based on pilot pitch production results, brain stimulation can temporarily induce tone-deafness in normal individuals, thus allowing us to assess our regional hypotheses using psychophysical measures that have been evaluated in experiments from the first aim. Examining the neural correlates of tone-deafness and creating a tone-deaf equivalent in normal subjects will offer new insights into the interactions of auditory and motor systems in the brain in normal and disordered speech as well as in non-speech communication.