Using Neuroimaging to Test Models of Speech Motor Control

为了让听者理解，说话者必须准确地从他或她的语言中发出声音。虽然这对大多数人来说似乎毫不费力，但实际的语音产生涉及复杂的心理和生理过程，包括语音肌肉的激活和声道中精确定时的运动（例如，嘴巴、下巴等动作的组合）。个体的言语器官的独特性质（例如，嘴的大小），再加上这些特性在一生中的发展变化，将直接影响每个人发出语音的方式。人类的大脑是如何完成这一壮举的不断调整控制声道，使它总是产生所需的声音？在美国国家科学基金会的支持下，研究人员将研究说话过程如何涉及大脑预测感官反馈，并在反馈与预测不匹配时纠正声道的控制。虽然先前的研究表明，这种预测和纠正过程确实发生在说话过程中，但关于大脑中的电路如何完成这一过程的信息很少。在拟议的研究中，研究人员将检查说话过程中对音频反馈扰动（音调，振幅或共振峰频率的短暂变化）的神经反应的时间过程。他们将使用脑磁图（MEG）和皮层脑电图（ECOG）方法记录正常人和癫痫患者，癫痫患者的大脑中植入电极以定位癫痫发作。这两种方法都能以毫秒级的时间分辨率记录大脑中的神经活动，这些实验的结果将允许测试不同的模型，这些模型被提出来解释语言运动控制的神经基础。这项研究的结果将有助于将说话的控制与运动控制研究的其他领域中所知的联系起来，并导致对人类运动控制的更全面的理解。使用先进的功能性神经影像学来研究说话的神经基础将提供一个特殊的机会来培训和教育广泛的研究生，博士后培训生和医学生谁将参与研究。拟议的研究还将进一步发展多用户研究设施，特别是在UCSF生物磁成像实验室，该实验室拥有美国数量有限的MEG扫描仪设施之一。

To speak so a listener understands, the speaker has to accurately produce the sounds from his or her language. While this may seem effortless for most people, the actual speech production involves complex mental and physical processes involving the activation of speech muscles and the precisely timed movements in the vocal tract (e.g., the combination of movements in the mouth, jaw, and so on). The unique properties of the individual's speech organs (e.g., size of mouth), combined with the developmental changes of these properties over a lifetime, will directly influence the way speech sounds are produced by each individual. How does the human brain accomplish this feat of continually tuning the control of vocal tract so that it always produces the sounds desired? With support from the National Science Foundation, the investigators will study how the speaking process involves the brain predicting the sensory feedback and correcting the control of the vocal tract when the feedback does not match the prediction. While previous research suggests that this prediction and correction process does occur during speaking, there is little information about how the circuitry in the brain would accomplish such a process. In the proposed research the investigators will examine the timecourse of neural responses to audio feedback perturbations (brief changes in pitch, amplitude, or formant frequencies) during speaking. They will use magnetoencephalography (MEG) and electrocorticography (ECOG) methods to record normal individuals and epilepsy patients who have electrodes implanted in their brain to localize seizures. Both methods allow neural activity in the brain to be recorded at a millisecond time resolution.The results of these experiments will allow for the testing of different models that have been proposed to explain the neural substrate of speech motor control. The outcome of the research will facilitate relating the control of speaking to what is known in other domains of motor control research, and lead to a more complete understanding of the control of movements in humans. The use of advanced functional neuroimaging to study the neural basis of speaking will provide a special opportunity to train and educate a wide range of graduate students, post-doctoral trainees, and medical students who will get involved in the research. The proposed research will also further the development of multi-user research facilities, especially at the UCSF Biomagnetic Imaging Laboratory that has one of a limited number of MEG scanner facilities in the US.