Subcortical neural basis of hearing in noise

描述(申请人提供)：听觉系统的基本功能是允许听者检测信号。这需要在安静和嘈杂的环境中进行。老年人和听力受损的人在嘈杂环境中探测声音的能力受到影响，即使使用辅助听力设备也是如此。本项目的目标是确定灵长类动物耳蜗核(CN)和下丘(IC)在安静和嘈杂环境中调节检测的神经机制。对噪声的检测依赖于听觉传出通路，只有在清醒和行为正常的生物体中才能完全发挥作用。灵长类动物是这项研究的选择，因为它们与人类的系统发育相似，以及灵长类动物和人类脑干的相似性，这与其他哺乳动物不同。对听觉和其他感觉系统的研究表明，对噪声中信号的反应通过抑制噪声的影响而增强，这种抑制影响抑制了噪声的影响，同时允许信号反应得到表达。IC内的局部处理增加了抑制，特别是宽带抑制，这消除了对噪声的响应，同时保持了对信号的响应，并调节了检测，从而使ICC响应与IC响应的关系比CN更好。该项目建议通过记录清醒和行为灵长类动物耳蜗核和下丘的单个单位反应，并将它们与同时测量的行为反应联系起来，来检验这些假说。总体而言，这项研究将有助于确定一些使我们能够在自然环境中探测和感知声音的机制。 公共卫生相关性：本建议中描述的实验旨在调查在噪音中对声音的神经生理反应，以及它们与同时测量的清醒和行为灵长类动物的检测表现的相关性。这些研究将为今后研究听力损失后听觉系统的反应变化，以及研究声场景分析的神经生理学基础奠定基础。最后，对两个相互连接的皮质下区域的反应特性和神经元与行为之间的相关性的评估将使我们更好地了解听觉系统中的皮质下回路，以及大脑一般使用的信号处理策略，并将有助于皮质下辅助听力植入物的设计和放置。

DESCRIPTION (provided by applicant): The basic function of the auditory system is to allow listeners to detect signals. This needs to happen in both quiet and noisy environments. The ability to detect sounds in noisy environments is compromised in the elderly and the hearing impaired, even with assistive hearing devices. The goal of this project is to determine the neuronal mechanisms in the cochlear nucleus (CN) and inferior colliculus (IC) of primates that mediate detection in quiet and noisy environments. Detection in noise depends on auditory efferent pathways that are fully functional only in awake and behaving organisms. Primates are the choice for this study due to their phylogenetic similarity with humans, as well as the similarity of the primate and human brainstem, which are different from other mammals. Studies in auditory and other sensory system have shown that responses to signals in noise are enhanced by inhibitory influences that suppress the effects of the noise while allowing the signal response to be expressed. Local processing within the IC increases the inhibition, specially wideband inhibition, which cancels the responses to noise while maintaining responses to signals, and mediating detection, thereby rendering ICC responses better related to IC responses than CN. This project proposes to test these hypotheses by recoding single unit responses in the cochlear nucleus and inferior colliculus in awake and behaving primates, and relating them to simultaneously measured behavioral responses. Overall, this study will help determine some of the mechanisms that allow us to detect and perceive sounds in natural environments. PUBLIC HEALTH RELEVANCE: Experiments described in this proposal are designed to investigate the neurophysiological responses to sounds in noise, and their correlation with simultaneously measured detection performance in awake and behaving primates. These studies will lay the foundation for future studies investigating the response changes in the auditory system after hearing loss, and for those investigating the neurophysiological basis of acoustical scene analysis. Finally, evaluation of response properties and the correlations between neurons and behavior at two connected sub-cortical areas will allow us a better understanding of sub-cortical circuitry in the auditory system, and signal processing strategies used by the brain in general, and will help in the design and placement of sub-cortical assistive hearing implants.