Efferent inhibitory mechanisms in binaural processing

描述（由申请人提供）：拟议的研究调查了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接受来自高级核团的抑制性传出。在鸟类中，对耳蜗核和双耳NL的抑制性反馈产生于位于第二和第三级核腹侧的一对不同的核团。这个优雅的安排系统在鸟类提供了一个独特的机会，获得一个机械和整体的理解的作用，抑制传出在功能明确的电路的听觉系统。本研究的长期目标是进一步了解传出反馈对声音定位的贡献。具体目标是：1）评估传出抑制对鸟类耳蜗核反应特性的贡献; 2）评估SON神经元群的反应特性和分类; 3）确定SON的连合连接的作用。将在这个建议中进行测试的模型涉及的作用，这种抑制电路均衡传入输入双耳计算。在20世纪70年代的双耳功能模型中已经提出了这种均衡过程的要求，但这种系统的存在尚未得到证明。拟议研究的结果可能对许多听力障碍有直接影响，特别是治疗包括双侧听觉假体的深度耳聋患者。与单耳条件相比，双耳听觉提供了检测移动信号、诸如语音的噪声中的信号以及声音位置的优点。这些研究将加强对双耳处理的中枢机制的理解，这些信息可能有助于改善听力受损者的治疗策略，特别是双侧治疗的人工耳蜗植入者。本计画将探讨双耳听觉的中枢机制。双耳听觉对于听者区分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依赖于对听觉脑功能的理解。拟议的实验将集中在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.