The Neural Basis of Perceptually-Relevant Auditory Modulations in Humans

描述（由申请人提供）：听觉神经科学的目标之一是了解语音和其他自然声音是如何在人类听觉皮层中分析和编码的。一个主要的发现是，感知和语音处理的声学信号中的时间调制的影响至关重要。然而，识别人类的生理机制，分析感知相关的时间调制提出了相当大的技术挑战。细胞外记录方法是研究基于时间的神经编码机制的理想方法，但它们通常限于单个听觉区域，并且不能普遍用于人类受试者。脑磁图（MEG）是一种非侵入性工具，适用于人类，记录来自整个大脑的高速神经信号，但代价是空间分辨率明显较粗。幸运的是，最近的工作表明，调查的神经编码的声学调制确实可以进行使用脑磁图与人类受试者。因此，脑磁图和细胞外记录都可以采用，以互补的方式，来研究时间调制是如何编码的听觉皮层。这项研究计划的目标是了解这些声学调制，语音和其他自然声音的构建模块是如何在听觉皮层中编码的。声学调制的编码研究嵌入在一个嘈杂的背景下，在一个自然的听觉场景，或调制的频率和幅度，独立和同时，在语音。该研究计划采用平行的实验组：一组使用MEG记录人类听觉皮层，另一组使用动物模型中的细胞外记录方法。通过记录单个神经元、细胞外局部场电位和整个皮层的信号，我们有可能统一不同的神经编码方案，在神经层级中上下对声音调制进行编码。 公共卫生相关性：最近的研究表明，各种听力和认知障碍是由声音的时间处理问题引起的（例如发育性语言障碍，以及由于衰老、听神经病或人工耳蜗植入引起的听力障碍）。目前的工作将提供新的实验方法，以及丰富的经验数据库在正常人的大脑皮层的时间处理，然后可以在临床环境中使用。

DESCRIPTION (provided by applicant): One of the goals of auditory neuroscience is to understand how speech and other natural sounds are analyzed and encoded in the human auditory cortex. One major finding is that perception and speech processing are crucially affected by temporal modulations in the acoustic signal. However, identifying in humans the physiological mechanisms that underlie the analysis of perceptually-relevant temporal modulations presents a considerable technical challenge. Extracellular recording methods are ideal for the investigation of time-based neural coding mechanisms, but they are typically limited to a single auditory area and cannot be generally used in human subjects. Magnetoencephalography (MEG) is a non-invasive tool, suitable for use in humans that records high-speed neural signals from the entire brain, though at the cost of significantly coarser spatial resolution. Fortunately, recent work has shown that investigations of the neural coding of acoustic modulations can indeed be conducted using MEG with human subjects. Thus MEG and extracellular recording can both be employed, in complementary ways, to investigate how temporal modulations are encoded by auditory cortex. The goal of this proposed research program is to understand how these acoustic modulations, the building blocks of speech and other natural sounds are encoded in auditory cortex. The acoustic modulations whose encoding is investigated are either embedded in a noisy background, as in a natural auditory scene, or modulated in both frequency and amplitude, independently and simultaneously, as in speech. The research program employs parallel sets of experiments: one set using MEG to record from human auditory cortex, and the other using extracellular recording methods in an animal model. With recordings from individual neurons, from the extracellular local field potential, and from the whole cortex, it may be possible to unify the different schemes used to neurally encode acoustic modulations, up and down the neural hierarchy. PUBLIC HEALTH RELEVANCE: Recent research suggests that a variety of hearing and cognitive impairments result from problems in temporal processing of sounds (e.g. developmental language disorders, and hearing impairment due to aging, auditory neuropathy, or cochlear implants). The present work will provide novel experimental approaches, as well as a rich empirical database on cortical temporal processing in normal human subjects, that can then be used in clinical settings.