Subcortical neural basis of hearing in noise

描述（由申请人提供）：听觉系统的基本功能是让听者检测信号。这需要在安静和嘈杂的环境中进行。老年人和听力受损者在嘈杂环境中探测声音的能力受到损害，即使有辅助听力设备。本项目的目的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介导检测的神经元机制。对噪音的探测依赖于听觉传出通路，而听觉传出通路只有在清醒和有行为的生物体中才完全发挥作用。由于灵长类动物与人类的系统发育相似，以及灵长类动物与人类脑干的相似性，这与其他哺乳动物不同，因此选择灵长类动物作为本研究的对象。听觉和其他感觉系统的研究表明，对噪声信号的反应通过抑制影响而增强，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，它在保持对信号的响应的同时消除了对噪声的响应，并介导了检测，从而使ICC响应与IC响应的相关性优于CN。本项目拟通过重新记录清醒和行为灵长类动物的耳蜗核和下丘的单一单元反应，并将它们与同时测量的行为反应联系起来，来验证这些假设。总的来说，这项研究将有助于确定我们在自然环境中探测和感知声音的一些机制。

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.