DEVELOPMENT OF SOUND LOCALIZATION

这是一个研究职业发展奖的要求，以解决如何 时间编码在听觉系统的发育过程中出现。 的 对时间排序输入的分析对于处理声音和语音都是不可或缺的。 位置信息和诸如语音的通信信号。 机制 在鸟类的听觉中， 脑干 在鸟类中，听觉神经纤维进入大脑， 终止于耳蜗角核和耳蜗核 大细胞的 大细胞核向 板状核支持耳间时间的编码和测量 差异 在板层核，大细胞轴突形成延迟 留置权，以创建地图的耳间时间差，这是利用 突触后符合探测器 在生命的最初几个星期，幼鸟的头会加倍 使其受到耳间信号的影响。 髓鞘的形成 板状核内的大细胞延迟线出现在 在这段时间里，最大的头部生长。 末以来 延迟线电路的髓鞘形成在功能上是重要的，我们将 研究髓鞘基因的发育概况以及 调节它们在脑干听觉核团中的表达。 研究 要求为这些试验提供培训支助。 我们的意图是 将该基因表达的时间与生理和 延迟线电路的解剖学成熟。 在研究髓鞘形成的同时，我们还将检查 时间编码的发展，在调整和组装的地图， 耳间时差 大细胞核内的神经元 而椎板编码听觉刺激的时间。 我们将 确定这种时间编码是如何发展的。 在成年鸟中， 椎板神经元通过同时激活它们的 同侧和对侧输入，通过重合检测机制。 由于突触前输入的时间对于巧合至关重要 检测，我们将确定何时输入的“正确”定时是 办妥了一批 调整这些输入的机制是 一般利益，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。 获得刚果民盟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。 的 我在必要的技术专长方面的主要缺陷是分子 生物学 必须了解系统是如何组装的， 在发展过程中的变化，以及发展的里程碑是什么。 由于延迟线轴突的延迟髓鞘形成似乎是 这些里程碑，已要求支持，以改善我的分子 在M博士的帮助下学习生物学技能。杜布瓦·达尔克在NIH。 该奖项 也会给我必要的时间来完成我的研究目标， 这对我长期的科学进步有很大的帮助。 这 申请也得到了动物学系主任的支持， 马里兰州大学。

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.