Studies of the Central Auditory System

描述（由申请人提供）：我们的长期目标是了解听力的神经机制。所有关于声音的信息都是由听觉神经的活动模式编码的。由于耳蜗核是听神经输入的强制性接受者，因此它是研究声刺激如何转化为神经密码并随后发送到大脑的关键部位。耳蜗核神经元被组织成可定义的组，它们共享共同的输入、细胞机制和轴突目标。通过连接不同细胞类型的结构和功能，我们试图了解它们在听力中的作用。最终，这种知识将使我们能够解释由耳聋或噪声引起的损伤对声学处理的影响所导致的结构异常。在这个应用中，我们建议研究耳蜗核腹侧分裂的多极细胞。这些细胞的轴突以耳蜗核中的其他神经元为目标。它们还投射到几乎所有的脑干和中脑听觉通路结构。多极神经元由几个不同的细胞亚类组成。我们将使用途径追踪和免疫细胞化学技术来研究不同类别的轴突靶点的结构和神经化学。我们将采用离体全脑的体外制备来研究亚类内的活动如何影响其轴突目标。从两种类型的实验中获得的信息将导致不同细胞类型的结构和功能数据之间的联系。这种结合解剖学和生理学的方法来研究多极细胞，将使我们能够确定它们的编码信息是如何在大脑中分布的，将影响双耳听力模型，并可能为人类脑干植入物的新设计提供建议。

DESCRIPTION (provided by applicant): Our long-range goal is to understand the neural mechanisms of hearing. All information about sound is encoded by patterns of activity in the auditory nerve. By virtue of its position as the obligatory recipient of auditory nerve input, the cochlear nucleus is a key site to study how acoustic stimuli are translated into neural codes that are then sent to the brain. Cochlear nucleus neurons are organized into definable groups that share common inputs, cellular mechanisms, and axonal targets. By linking structure and function for different cell types, we seek to understand their roles in hearing. Ultimately, this kind of knowledge should allow us to interpret structural anomalies resulting from deafness or noise-induced damage in terms of their effect on acoustic processing. In this application, we propose to study multipolar cells in the ventral division of the cochlear nucleus. The axons of these cells target other neurons in the cochlear nucleus. They also project to nearly every brain stem and midbrain structure in the auditory pathway. Multipolar neurons are comprised of several distinct subclasses of cells. We will use pathway tracing and immunocytochemical techniques to study the structure and neurochemistry of different classes with respect to their axonal targets. We will employ an in vitro preparation of the isolated whole brain to study how the activity within a subclass influences its axonal targets. Information obtained from both types of experiments will result in links between structural and functional data for different cell types. This combined anatomic and physiologic approach to the study of multipolar cells will allow us to determine how their encoded messages are distributed in the brain, will impact models of binaural hearing, and may suggest new designs for human brain stem implants.