Efferent inhibitory mechanisms in binaural processing

描述(由申请人提供)：拟议的研究调查中枢听觉系统的传出抑制回路。在鸟类和哺乳动物中，参与声音定位的神经中枢都接受来自高阶核团的抑制性传出。在鸟类中，对耳蜗核和双耳NL的抑制性反馈来自一对不同的核团，它们位于二阶和三阶核团的腹侧。在鸟类中，这一优雅的系统安排提供了一个独特的机会，可以从机械和整体上了解抑制性传出物质在听觉系统功能明确的回路中的作用。本研究的长期目标是加深我们对传出反馈对声音定位的贡献的理解。其具体目的是：1)评价传出抑制对鸟类耳蜗核反应特性的贡献；2)评价反应特性和SON神经元群体的分类；3)确定SON的连合联系的作用。将在本提案中测试的模型涉及到这种抑制电路的作用，该抑制电路用于均衡双耳计算的传入输入。早在1970年代的双耳功能模型中就提出了对这种均衡过程的要求，但还没有证明这种系统的存在。拟议中的研究结果可能对许多听力障碍有直接影响，特别是对包括双侧听觉假体治疗的深度失聪患者。与单耳情况相比，双耳听力在检测运动信号、语音等噪声中的信号和声音定位方面具有优势。这些研究将加强对双耳处理的中枢机制的了解，这些信息可能有助于完善听力障碍者的治疗策略，特别是双侧人工耳蜗术后的治疗策略。这项提案将研究双耳听力的中心机制。双耳听力对于听者辨别噪声中的信号以及声源的位置至关重要。现代听觉假体设备的发展有赖于对听觉脑功能的了解。拟议的实验将集中于揭示听觉系统中双耳计算的原理。

DESCRIPTION (provided by applicant): The proposed study investigates an efferent inhibitory circuit of the central auditory system. In both birds and mammals, the neural centers involved in sound localization receive inhibitory efferents from higher order nuclei. In birds, inhibitory feedback to the cochlear nuclei and binaural NL arise from a distinct pair of nuclei residing just ventral to the second and third order nuclei. This elegantly arranged system in birds provides a unique opportunity to gain a mechanistic and holistic understanding of the role of inhibitory efferents in a functionally well defined circuit of the auditory system. The long term goal of the study is to further our understanding of the contribution of efferent feedback to sound localization. The specific aims are: 1) Evaluation of the contributions of efferent inhibition to response properties in the avian cochlear nucleus; 2) Evaluation of response properties and classification of SON neuron populations; 3) Determine the role of the commissural connection of the SONs. The models that will be tested in this proposal involve the role of this inhibitory circuit for equalizing afferent inputs for binaural computations. The requirement for this equalization process has been proposed in models of binaural function that date to the 1970s, but the presence of such a system has not been demonstrated. The findings of the proposed studies could have direct implications for a number of hearing disorders, in particular, profoundly deaf patients whose treatment includes bilateral auditory prostheses. Binaural hearing provides advantages for detecting moving signals, signals in noise such as speech, and sound location compared to monaural conditions. These studies will enhance understanding of the central mechanisms of binaural processing, and this information may contribute to refinements of treatment strategies for the hearing impaired and in particular, bilaterally treated cochlear implant recipients. This proposal will investigate central mechanisms of binaural hearing. Binaural hearing is crucial for listeners to discriminate signals in noise as well as the location of sound sources. Development of modern auditory prosthetic devices relies on an understanding of auditory brain function. The proposed experiments will focus on revealing principles of binaural computations in the auditory system.