STUDIES OF TONAL INTERACTIONS IN THE AUDITORY SYSTEM

这是电生理学研究的竞争性更新。 听神经和耳蜗腹侧核的刺激编码 完整的成年猫科动物。有两条独立但相关的线路 研究。第一行是神经学研究的继续。 对声音刺激进行编码。这些活动的目标是确定 听觉反应的非线性特征如何结合在一起来定义 神经放电模式，并检查频率和 强度信息被编码在听神经中，并且 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 响应中谐和波谱的编码 关于一阶和二阶听觉神经元的研究 复合体神经加工中的刺激转换 听神经和耳蜗核之间的音调，以及 听神经纤维反应的过度适应研究 在高刺激频率下。在需要检验的假设中 是刺激波形的精细结构决定了 激发和抑制的瞬时大小，即 相敏感的耳蜗核神经元的反应是 在数量上但在质量上与 听神经纤维和高频“钩”区 猫的耳蜗在新陈代谢上是脆弱的。这些研究 有助于阐明潜在的耳蜗学机制 复杂音调和语音的神经编码，到 理解人类对复杂色调的感知，以及对 频率分析和基音感知理论的验证。 第二条研究线包括对以下方面的定量研究 通过条带传输的电刺激的神经编码 多通道人工耳蜗术。这些内容的目标是描述 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 植入者行为表现的神经生理学基础 人类。具体项目包括详细的量化分析 作为电刺激的听神经纤维反应 参数是系统变化的，电生理 耳廓内电流扩散和电极的测量 通道隔离，神经纤维群对语音的反应 通过当代语音处理方案编码的刺激，以及 研究对电刺激进行编码的替代方法 强度，从而扩大动态范围。这些研究是相关的 了解耳蜗所含信息的类型和限制 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.