ENVIRONMENT INFLUENCES UPON AUDITORY DEVELOPMENT

环境对听觉发育的影响

• 批准号: 3215836
• 负责人: Allen F. Ryan
• 金额: $ 16.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-07-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3215836
• 关键词: acoustic nerve; afferent nerve; auditory deprivation; auditory feedback; auditory nuclei; auditory pathways; auditory stimulus; cochlea; cochlear nerve; communication disorders; controlled environment; efferent nerve; electron microscopy; electrophysiology; evolution; gerbil /jird; hearing disorders; infant animal; innervation; neural plasticity; neural transmission; neuroanatomy; neurogenesis; newborn animals; noise; organ of Corti; sound frequency; synapses

Clinical evidence suggests that hearing loss during infancy and childhood increases the probability of language and learning disabilities. Experimental data suggest that such communicative disorders are due in part to changes in auditory system anatomy and function, induced by lack of acoustic experience during development. These considerations indicate the importance of understanding auditory development, and the degree to which experience can influence its course. Developmental studies can also provide insight into the function of the adult auditory system. The proposed research will investigate several current problems in normal auditory development, including: the afferent and efferent innervation of the organ of Corti; the growth of neurons and synapses in the cochlear nuclear complex; levels of neural growth factors in the developing inner ear and cochlear nucleus; and early neural function in the VIIIth nerve and cochlear nucleus. The neural plasticity of auditory development will also be studied in a series of experiments. The effects of profound acoustic deprivation during auditory development upon the function of the auditory system will be assessed. Acoustic deprivation will include surgical removal of the middle ear transmission apparatus to provide approximately 60 dB of isolation from air-conducted, and 40 dB of isolation from bone-conducted, stimuli. A sound- attenuated rearing environment will provide an additional 80 dB of isolation from external sounds. Mechanical displacement of the stapes with a piezoelectric driver is used to restore auditory function. Also, tetrodotoxin blockade of neural transmission will be used to delay the normal onset of normal auditory function. The effects of this procedure on VIIIth nerve fiber and cochlear nucleus firing patterns will be evaluated. In addition, animals will be reared in an environment restricted to a 1/3 octave band of noise. Their innervation patterns will be assessed in adulthood to determine whether experience produces preferential representation in the central auditory pathway. The influence of neonatal lesions of cochlea on the development of the olivocochlear efferents will be studied, and the effects of manipulation of growth factors on the neural development of the cochlea and cochlear nucleus will also be evaluated.

临床证据表明，婴儿期和 童年增加了语言和学习的可能性 残疾。 实验数据表明，这种沟通方式 疾病部分是由于听觉系统解剖结构的变化和 功能，由于缺乏声学经验而引起 发展。 这些考虑因素表明了以下事项的重要性： 了解听觉发育及其程度 经验可以影响其进程。 发展研究可以 还可以深入了解成人听觉的功能 系统。 拟议的研究将调查当前的几个问题 正常的听觉发育，包括：传入和传出 柯蒂氏器的神经支配;神经元的生长和 耳蜗核复合体中的突触；神经生长水平 内耳和耳蜗核发育的因素；和早 第八神经和耳蜗核的神经功能。 听觉发育的神经可塑性也将被研究 在一系列的实验中。 深刻的声学效果 听觉发育过程中听觉功能的剥夺 将评估听觉系统。 声剥夺将 包括手术切除中耳传输装置 提供大约 60 dB 的空气传导隔离， 与骨传导刺激的隔离度为 40 dB。 一声—— 减弱的饲养环境将提供额外的 80 dB 与外界声音隔离。 机械位移 带有压电驱动器的镫骨用于恢复听力 功能。 此外，河豚毒素会阻断神经传递 用于延迟正常听觉功能的正常发生。 这 该手术对第八神经纤维和耳蜗的影响 将评估核放电模式。 此外，动物 将在仅限于 1/3 倍频程的环境中饲养 的噪音。 他们的神经支配模式将在成年后进行评估 确定经验是否会产生优惠 中枢听觉通路的表征。 的影响 新生儿耳蜗病变对橄榄耳蜗发育的影响 将研究传出神经，以及操纵的效果 生长因子对耳蜗神经发育的影响 还将评估耳蜗核。