Neural correlates of sound localisation: across-frequency integration and adaptation

声音定位是动物和人类的一项重要能力。在过去的十年里，声音到底是如何定位的，以及这些信息在大脑中是如何表示的，一直是有争议的讨论。这项提议将集中在一个声音定位参数的神经表示上，即听觉专家谷仓猫头鹰大脑中的耳间时间差。本研究的目的是探讨谷仓猫头鹰下丘适应与频率整合的关系。提出了三个工作方案，并采用了由第一个或参考刺激和第二个或测试刺激组成的刺激范式。这一范式模拟了谷仓猫头鹰狩猎的行为情景。在持续刺激期间发生的适应在下文中称为尖峰频率适应。相比之下，如果第一个刺激之后是第二个刺激，那么第一个刺激对第二个刺激的影响将被称为反应适应。第一个工作包旨在产生关于尖峰频率适应和响应适应的基本数据。在工作包2中，将使用双重记录来同时研究下丘外核的两个位置的反应，一个对应于参考刺激的位置，另一个对应于测试刺激的位置。工作包3将跨频率整合的研究与适应研究结合起来，试图揭示这两种现象是否以及如何相关。申请人期待着关于跨频率整合和适应的神经机制及其关系的重要新发现，以及关于神经系统如何处理发生在行为相关情况下的适应的新见解。

Sound localization is an important ability of animals and man. How exactly sounds are localized and how this information is represented in the brain has been controversially discussed in the last decade. This proposal will concentrate on the neural representation of one sound-localization parameter, the interaural time difference in the brain of an auditory specialist, the barn owl. The goal of this proposal is to investigate the relation between adaptation and frequency integration in the inferior colliculus of the barn owls inferior colliculus. Three work packages are proposed, and a stimulus paradigm consisting of a first or reference stimulus and a second or test stimulus is employed. This paradigm mimics the behavioral situation in barn-owl hunting. An adaptation occurring during an ongoing stimulus will be called spike-frequency adaptation in the following. By contrast, if a first stimulus is followed by a second stimulus, the influence of the first on the second stimulus will be called response adaptation. The first work package is designed to yield basic data on spike-frequency adaptation and response adaptation. In work package 2 double recordings will be used to study simultaneously the responses at 2 locations in the external nucleus of the inferior colliculus, one corresponding to the location of the reference stimulus and the other corresponding to the location of the test stimulus. Work package 3 combines investigations of across-frequency integration with the study of adaptation and tries to unravel whether and how these two phenomena are related. The applicant expects important new findings about neural mechanisms underlying both across-frequency integration and adaptation and their relation and new insights in how the nervous system handles adaptation occurring in behaviorally relevant situations.