COCHLEAR NERVE DEVELOPMENT

这项研究将考察出生后大脑结构和功能的变化。 哺乳动物的耳蜗神经元是听力成熟的基础。这个 耳蜗神经模式的发展将在一个时代被绘制出来- 用体内标准和新设计的新生儿沙土鼠分级系列 体外辣根过氧化物酶示踪技术应用于完整和 切开的耳蜗线。 大鼠耳蜗神经元束发育的平行体外研究 科尔蒂沙鼠器官的长期器官培养将检查 发育中耳蜗神经元竞争的潜在作用 耳蜗毛细胞成熟模式的传入和传出 神经支配。 指导植物生长发育和修剪的超微结构 耳蜗神经元束及其目标毛细胞将在这两个 经选择的HRP序列重建完整和培养的耳蜗组织 用高压电子显微镜(HVEM)标记传入终末。 出生后耳蜗神经元对声音反应特性的变化 将在耳蜗螺旋内的特定位置使用一种新的 新生儿沙土鼠螺旋神经节细胞记录方法。 这个国家有超过25万儿童听力受损。 由于某种形式的先天性感音神经性听力损失。建议数 研究应提供关键的规范性数据，这些数据是 了解疾病改变疾病发展的机制 听觉外周的结构和功能。

This study will examine the postnatal changes in structure and function of mammalian cochlear neurons which underlie the maturation of hearing. The development of cochlear innervation patterns will be charted in an age- graded series of neonatal gerbils using standard in vivo and newly devised in vitro Horseradish peroxidase tract-tracing methods applied to intact and acutely-excised cochleae. Parallel in vitro studies of the development of cochlear neuron arbors in long-term organotypic cultures of the gerbil organ of Corti will examine the potential role of neuronal competition between developing cochlear afferents and efferents in sculpting a mature pattern of cochlear hair cell innervation. The ultrastructural events which guide the formation and pruning of cochlear neuron arbors with their target hair cells will be studied in both intact and cultured cochleae by serial reconstruction of selected HRP- labeled afferent terminals using high voltage electron microscopy (HVEM). Postnatal changes in the response properties of cochlear neurons to sound will be explored at specific sites within the cochlear spiral using a new spiral ganglion cell recording approach in neonatal gerbils. Over a quarter of a million children in this country are hearing impaired due to some form of congenital sensorineural hearing loss. The proposed studies should provide crucial normative data which are required for understanding the mechanisms by which disease alters the development of structure and function in the auditory periphery.