NEURAL ENCODING OF COMPLEX SOUNDS

描述(由申请人提供)：正常的听觉系统具有从环境中提取与行为相关的声信号的精细而适配的过程，特别是在具有挑战性的听条件下，例如在存在竞争信号或背景噪声的情况下。然而，从生理学角度来看，人们对这些过程知之甚少。这个建议的目的是了解一种特殊的听觉加工非线性(听觉光谱对比度调谐)的神经生物学，因为它与哺乳动物听觉系统中噪声发声的表征有关。目标1将包括测量听觉神经元用来估计光谱对比度的声音频率范围。这些信息将被证明对理解对比度调节是如何从生物学上计算的至关重要。目标2将确定调整到光谱对比度的神经元的输入/输出函数的编码部分。这一功能的性质将允许对神经元在稍后的处理阶段如何读出这一特定的处理特征做出推断。Aim 3将直接测试对比度调整的神经元对嵌入背景噪声中的发声的反应，期望噪声发声将在这些神经元中产生尖峰反应，随着噪声量的增加，这些反应携带更多的信息，直到达到一个极限。这项研究完成后，将有助于更好地理解中央听觉系统中潜在的重要反应特性，这与工程降噪系统具有潜在的相关性，对于依赖听力假体进行日常生活行为的个人来说，这可能具有巨大的潜力。这个项目解决了我们的长期目标，即更清楚地了解环境和交流声音是如何在嘈杂条件下在哺乳动物的听觉系统中编码的。我们将通过探索灵长类听觉皮质神经元特殊的非线性处理特征是如何产生的，如何编码刺激特征以及如何对噪声退化的发声做出反应来实现这一目标。最终，这些信息可能有助于改进算法，使助听器和人工耳蜗等听觉假体设备在日常嘈杂环境中更好地发挥作用。

DESCRIPTION (provided by applicant): The normal auditory system possesses exquisitely well-adapted processes for extracting behaviorally relevant acoustic signals from the environment, especially under challenging listening conditions such as in the presence of competing signals or background noise. These processes are poorly understood physiologically, however. The objective of this proposal is to understand the neurobiology of a particular auditory processing nonlinearity (auditory spectral contrast tuning) as it relates to noisy vocalization representation in the mammalian auditory system. Aim 1 will involve measuring the sound frequency range that auditory neurons use for making estimates of spectral contrast. This information will prove critical for understanding how contrast tuning is computed biologically. Aim 2 will determine the coding portion of the input/output function for neurons tuned to spectral contrast. The nature of this function will allow inferences to be made about how this particular processing feature is read out by neurons at a later processing stage. Aim 3 will directly test the responses of contrast-tuned neurons to vocalizations embedded in background noise, with the expectation that noisy vocalizations will produce spiking responses in these neurons that carry more information as the amount of noise increases, up to a limit. When completed, this research will result in an improved understanding of a potentially important response property in the central auditory system with potential relevance for engineered noise-reduction systems, which could have great potential for individuals reliant upon a hearing prosthesis for acts of daily living. This project addresses our long-term goal of understanding more clearly how environmental and communication sounds are encoded in the mammalian auditory system under noisy conditions. We will achieve this goal by exploring how particular nonlinear processing features of neurons in primate auditory cortex are created, encode stimulus features and respond to vocalizations degraded by noise. Ultimately, this information may aid in refining algorithms that could allow auditory prosthesis devices such as hearing aids and cochlear implants to function better in everyday noisy environments.