DEVELOPMENT OF SOUND LOCALIZATION

这是对研究职业发展奖的请求，以解决如何 时间编码是在听觉系统发育过程中产生的。这个 对时间顺序输入的分析是处理这两种声音所必需的 位置信息和诸如语音的通信信号。机制 时间编码可能在鸟类的听觉中特别容易获得 脑干。在鸟类中，听觉神经纤维进入大脑并分裂为 终止于耳蜗角状核和耳蜗核 巨细胞。大细胞核向大脑皮质的投射 板层核支持耳间时间的编码和测量 不同之处。在板层核，大细胞轴突形成延迟。 留置权创建耳间时差地图，由 突触后符合探测器。 在生命的最初几周里，幼鸟的头部会加倍 在大小上，使其受制于变化的耳间线索。细胞的髓鞘形成 板层核内的大细胞延迟线出现在 发展，在这个人头增长最快的时期。自晚些时候以来 延迟线电路的髓鞘形成在功能上意义重大，我们将 研究髓鞘基因的发育概况及其影响因素 调节它们在脑干听觉核团中的表达。研究 要求为这些实验提供培训支持。我们的意图是 将这一基因表达的时间与生理和 延迟线电路的解剖成熟。 在研究髓鞘形成的同时，我们还将研究 地图整编过程中时间编码的发展 两耳间时差。大细胞核内的神经元 而板层编码听觉刺激的时序。我们会 确定这一次编码是如何发展的。在成鸟体内，细胞核 板层神经元的最大兴奋是通过同时激活它们的 IPSI--和对侧输入，通过符合检测机制。 因为突触前输入的时间对符合是至关重要的 检测时，我们将确定输入的“正确”时间是 已实现。调整这些输入的基本机制是 普遍利益，因为许多发展模式取决于选择 按时间顺序输入。拟议中的研究在很大程度上依赖于劳动力 密集的生理学实验。 获得RCD奖将使我能够追求我的长期目标 比较髓鞘相关基因表达的时间与 延迟线电路的生理和解剖成熟。这个 我在必要的技术专长上的主要缺陷是分子 生物学。了解系统是如何组装的以及如何安装已变得至关重要 在开发过程中进行了修改，以及开发里程碑是什么。 由于延迟线轴突的延迟髓鞘形成似乎是 这些里程碑，已经请求支持来改进我的分子 在国立卫生研究院M.Dubois Dalq博士的协助下，生物技能。获奖名单 也会给我必要的时间来完成我的研究目标 对我长期的科学提高有很大的贡献。这 申请也得到了动物学系主任的支持 马里兰大学。

This is a request for a Research Career Development Award to address how time coding arises during the development of the auditory system. The analysis of temporally ordered inputs is integral to processing both sound location information and communication signals such as speech. Mechanisms of time coding may be particularly accessible in the bird's auditory brainstem. In birds, auditory nerve fibers enter the brain and divide to terminate in the cochlear nucleus angularis and the cochlear nucleus magnocellularis. The projection from the nucleus magnocellularis to the nucleus laminaris supports the encoding and measurement of interaural time differences. In the nucleus laminaris, the magnocellular axons form delay liens to create maps of interaural time differences which are tapped by postsynaptic coincidence detectors. During the first few weeks of life, the young bird's head more that doubles in size, subjecting it to changing interaural cues. The myelination of the magnocellular delay lines within the nucleus laminaris occurs late in development, during this period of maximum head growth. Since the late myelination of the delay line circuit is functionally significant, we will examine athe developmental profile of myelin genes and the factors that regulate their expression in the brainstem auditory nuclei. Research training support is requested for these experiments. Our intention is to compare the timing of this gene expression with the physiological and anatomical maturation of the delay line circuit. In parallel with the studies of myelination, we will also examine the development of time coding during the tuning and assembly of the map of interaural time differences. The neurons in the nucleus magnocellularis and laminaris encode the timing of the auditory stimulus. We will determine how this time coding develops. In the adult bird, nucleus laminaris neurons are maximally excited by simultaneous activation of their ipsi- and contralateral inputs, via a coincidence detection mechanism. Since the timing of the presynaptic inputs is critical to coincidence detection, we will determine when the "correct" timing of the inputs is achieved. The mechanism underlying the tuning of these inputs is of general interest, since many models of development depend upon selection of temporally ordered input. The proposed research depends heavily on labor intensive physiology experiments. Receipt of an RCD Award would enable me to pursue my long term goal of comparing the timing of myelin-related gene expression with the physiological and anatomical maturation of the delay line circuit. The major deficit in my necessary technical expertise has been molecular biology. It has become essential to know how the system is assembled and modified during development, and what the developmental milestones are. Since delayed myelination of the delay line axons appears to be one of these milestones, support has been requested to improve my molecular biology skills with the assistance of Dr. M. Dubois Dalq at NIH. The award would also give me the necessary time to accomplish my research goals and greatly contribute to my long term scientific enhancement. This application is also supported by the chair of the Zoology department at the University of Maryland.