Olivocochlear Reflex in Humans

人类的橄榄耳蜗反射

• 批准号: 6727453
• 负责人: JOHN J GUINAN
• 金额: $ 24.88万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6727453
• 关键词: acoustic nerve; auditory discrimination; auditory reflex; auditory stimulus; clinical research; cochlea; ear hair cell; efferent nerve; electrodes; handedness; human subject; olivocochlear bundle; otoacoustic emission; psychoacoustics; psychological tests; sensory signal detection; sound frequency; sound perception; visual stimulus

DESCRIPTION (provided by applicant): Despite advances in understanding many peripheral effects of activating medial olivocochlear (MOC) efferents to outer hair cells (OHCs), as well as the molecular mechanisms underlying those effects, the functional significance of MOC efferents in human audition remains controversial. Basic properties of the MOC reflexes, such as their frequency specificity, are poorly understood. Studies of human efferent function in attention, and detection and/or discrimination of signals, have given seemingly contradictory results, but no study has systematically varied parameters in an effort to resolve these issues. MOC fibers alter the state of the OHCs and thereby affect the generation of otoacoustic emissions (OAEs). Our approach is to use OAEs as a non-invasive assay of MOC activation levels in normal human subjects, and to compare activation levels in a variety of listening contexts. Substantial technical advances allow us to use only a single low-level probe tone, which we can demonstrate evokes little or no MOC activity, to measure MOC activation elicited reflexly by contralateral and/or ipsilateral sounds, or elicited by higher brain centers, and to determine whether these effects are produced by MOC efferents or middle-ear-muscles. To understand the functional organization of the human MOC system, we will determine in humans as functions of probe frequency: (Aim la) the relative strength of the ipsilateral, contralateral and bilateral MOC reflexes, (Aim lb) the frequency specificity of MOC reflexes, and (Aim lc) MOC reflex strength in terms of the changes in cochlear sensitivity produced. To determine if efferents affect cochlear tuning, we will (Aim 2) measure the changes in cochlear tuning produced by efferent activity. To address the functional significance of the MOC system, we will systematically measure MOC activation levels (Aim 3a) in psychophysical tasks in which we predict that MOC activation will aid performance (discrimination of transient signals in noise) and those in which no benefit is anticipated, and (Aim 3b) during selective attention to auditory vs. visual stimuli, or to one component of an auditory stimulus. The results of our experiments will provide the first comprehensive assessment of the functional organization of the human MOC system and should provide significant insight into the functional significance of the MOC system in human audition.

描述（由申请人提供）：尽管在理解激活外毛（MOC）对外毛细胞（OHC）激活内侧橄榄石（MOC）受托的许多外围作用方面的进展以及这些作用的分子机制，但MOC e节子在人体试听中的功能意义仍然存在争议。 MOC反射的基本特性（例如它们的频率特异性）知之甚少。人类传出功能在注意力以及对信号的检测和/或歧视中的研究似乎给出了矛盾的结果，但是没有研究的参数在解决这些问题方面具有多种多样的参数。 MOC纤维会改变OHC的状态，从而影响耳声发射（OAE）的产生。我们的方法是将OAE用作正常人类受试者中MOC激活水平的无创测定，并在各种听力环境中比较激活水平。实质性的技术进步使我们只能使用单个低级探针音调，我们可以证明几乎没有或没有MOC活性，以测量通过对侧和/或同侧声音反射的MOC激活，或者由较高的大脑中心引起，并确定MOC ferfers弱者或中等层次或中等角度或中等层次或中等角度。 To understand the functional organization of the human MOC system, we will determine in humans as functions of probe frequency: (Aim la) the relative strength of the ipsilateral, contralateral and bilateral MOC reflexes, (Aim lb) the frequency specificity of MOC reflexes, and (Aim lc) MOC reflex strength in terms of the changes in cochlear sensitivity produced.为了确定传出者是否影响人工耳蜗调整，我们将（AIM 2）衡量由传出活动产生的耳蜗调整的变化。为了解决MOC系统的功能意义，我们将系统地测量心理物理任务中的MOC激活水平（AIM 3A），在这些任务中，我们预测MOC激活将有助于性能（噪声中短暂信号的歧视），并且在选择性注意力的视觉刺激性刺激性刺激性或一位刺激性的刺激性刺激性刺激性或一位刺激性刺激性的过程中，并且（AIM 3B）预计无益处。我们的实验结果将对人类MOC系统的功能组织进行首次全面评估，并应为MOC系统在人类试听中的功能意义提供重大见解。