STUDIES OF TONAL INTERACTIONS IN THE AUDITORY SYSTEM

这是一个有竞争力的更新的电生理学研究， 听神经和耳蜗腹侧核的刺激编码 完整的成年猫 有两条独立但相关的路线 research. 第一行是对神经系统的研究的延续， 声音刺激的编码。 这些活动的目标是确定 听觉反应的非线性特征如何结合联合收割机来定义 神经放电模式，并检查频率和 强度信息被编码在听觉神经中， 在耳蜗核中转化。 具体项目需要 速率和同步抑制的定量分析，时间 响应中谐波复合体频谱的编码 第一和第二阶听觉神经元，调查 复杂神经加工中的刺激转换 听觉神经和耳蜗核之间的音调，以及 听神经纤维反应过度适应的研究 在高刺激频率下。 在有待检验的假设中 刺激波形精细结构决定了 激励和抑制的瞬时幅度， 耳蜗核神经元的相敏反应是 数量上但质量上与 听觉神经纤维，以及高频“钩”区域 是代谢脆弱的。 这些研究 有助于阐明耳蜗机制， 复杂音调和语音的神经编码， 理解人类对复杂音调的感知， 频率分析和音高感知理论的验证。 研究的第二条线包括定量研究， 神经编码的电刺激传递通过带状 多通道人工耳蜗 这些的目的是描述 深入了解听神经的基本特性和局限性， 纤维对电刺激的反应，并推断 植入后行为表现的神经生理学基础 人类 具体项目包括详细的定量分析 听觉神经纤维的反应 系统地改变参数，电生理学 脑内电流分布和电极测量 通道隔离，神经纤维群对语言的反应 通过当代语音处理方案编码的刺激，以及 检查编码电刺激的替代方法 从而扩大动态范围。 这些研究是相关的 理解耳蜗所传递的信息的类型和局限性 植入物能够编码，它们提供的数据可以 指导未来的语音处理器设计。

This is a competitive renewal of electrophysiological studies of stimulus coding in the auditory nerve and ventral cochlear nucleus of intact adult cats. There are two separate but related lines of research. The first line is a continuation of studies of neural coding of acoustic stimuli. The goals of these are to determine how nonlinear features of auditory response combine to define neural firing patterns and to examine ways that frequency and intensity information is encoded in the auditory nerve and transformed in the cochlear nucleus. Specific projects entail quantitative analyses of rate and synchrony suppression, temporal coding of frequency spectra of harmonic complexes in responses of first- and second-order auditory neurons, investigations of stimulus transforms involved in neural processing of complex tones between the auditory nerve and cochlear nucleus, and studies of excessive adaptation in auditory nerve fiber responses at high stimulus frequencies. Among the hypotheses to be tested are that stimulus waveform fine structure determines the instaneous magnitudes of both excitation and suppression, that responses of phase-sensitive cochlear nucleus neurons are quantitatively but not qualitatively different from responses of auditory nerve fibers, and that the high-frequency "hook" region of the cat cochlea is metabolically fragile. These studies contribute to the elucidation of cochlear mechanisms underlying the neural coding of complex tones and speech, to the understanding of human perception of complex tones, and to the validation of theories of frequency analysis and pitch perception. The second line of research consists of quantitative studies of neural coding of electrical stimuli delivered through a banded multi-channel cochlear implant. The goal of these is to describe thoroughly the basic properties and limitations of auditory nerve fiber responses to electrical stimuli and to infer the neurophysiological basis of behavioral performance in implanted humans. Specific projects include detailed quantitative analyses of auditory nerve fiber responses as electrical stimulus parameters are varied systematically, electrophysiological measurements of intracochlear current spread and electrode channel isolation, nerve fiber population responses to speech stimuli encoded via contemporary speech-processing schemes, and examination of alternative ways to encode electrical stimulus intensity so as to expand dynamic range. The studies are relevant to understanding the types and limits of information that cochlear implants are capable of encoding and they provide data that can guide future speech processor designs.