How does the efferent auditory system function in the neural encoding and perception of speech-in-noise?

传出听觉系统在噪声中语音的神经编码和感知中如何发挥作用？

• 批准号: 8833717
• 负责人: Spencer Smith
• 金额: $ 3.96万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-20 至 2017-08-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8833717
• 关键词: Academic achievement; Acoustic Nerve; Action Potentials; Address; Adult; Affect; Aging; Algorithms; Animal Experimentation; Animals; Auditory; Auditory Brainstem Responses; Auditory Perception; Auditory system; Biological Assay; Brain; Brain Stem; Child; Cochlea; Cochlear Implants; Code; Cognitive; Consensus; Contralateral; Data; Ear; Evaluation; External auditory canal; Feedback; Functional disorder; Goals; Hearing; Hearing Aids; Human; Impairment; Individual; Labyrinth; Language; Lead; Learning Disorders; Left; Masks; Measurement; Measures; Mechanics; Medial; Modeling; Nervous system structure; Neurobiology; Noise; Outcomes Research; Output; Participant; Patients; Perception; Physiological; Process; Reading; Recruitment Activity; Reflex action; Research; Role; Signal Transduction; Site; Speech; Speech Perception; Structure of tractus olivocochlearis; System; Time; Withdrawal; Work; base; disability; experience; improved; nerve supply; neural circuit; noise perception; otoacoustic emission; public health relevance; relating to nervous system; research study; response; social; speech processing

DESCRIPTION (provided by applicant): Severe difficulty understanding speech-in-noise causes social withdrawal, inhibits academic achievement, and limits vocational opportunities for those affected. Inexplicably, there are individuals who experience severe difficulty understanding speech-in-noise despite having normal hearing sensitivity, such as normally aging adults and children with reading, language, auditory processing, and learning disorders. The neurobiological basis of speech-in-noise deficits in these individuals is currently unknown, which limits evaluation and targeted treatment of this hearing disability. The efferent auditory system is the division of the auditory nervous system that is believed to fine-tune and filter auditory information as it ascends from the inner ears to the brain. This system has been studied extensively in animals, but far less is known about how it works in humans during speech-in-noise processing. Some evidence suggests that selective dysfunction in the efferent auditory system may cause severe difficulty hearing in noise while leaving hearing sensitivity intact. The proposed research investigates the function of one specific mechanism of the human efferent auditory system, the medial olivocochlear (MOC) bundle, in the neural encoding and perception of speech-in-noise in normal hearing adults and children. The MOC bundle is an efferent neural circuit, which has been shown to filter and suppresses background noise at the level of the inner ear in animals. This filter may allow less noise to be transcribed into neural code, which in turn improves perception of auditory signals in competing background noise. It remains unclear if the human MOC reflex is: a) an important efferent mechanism that reduces the effect of noise on the bottom-up neural encoding of speech, and b) modulated by top-down processes, such as active listening, to enhance hearing in noise. These issues will be addressed in two studies. The first study will involve measurements of speech-evoked neural activity from the auditory nerve and brainstem during MOC reflex activation to determine if this reflex improves the neural encoding of speech-in-noise. It is hypothesized that activation of the MOC reflex will improve the neural encoding of speech-in-noise at the level of the auditory nerve and brainstem. In the second study, participants will actively listen to an Auditory Stroop Task while the MOC reflex is engaged to determine if cognitive demands modulate the MOC reflex. It is hypothesized that more challenging listening conditions of the Auditory Stroop Task will have a greater impact on MOC reflex strength, indicating a modulatory relationship between the brain and inner ears. The outcomes of this research clarify the role of the efferent system in speech-in-noise processing and can be used to create targeted treatments and objective assessments for individuals with severe difficulties understanding speech-in-noise.

描述（由申请人提供）：严重的困难理解语音中的言语会导致社会撤退，抑制学术成就，并限制受影响者的职业机会。莫名其妙的是，尽管有正常的听力敏感性，例如正常老年人和有阅读，语言，听觉处理和学习障碍的儿童，但仍有一些人遇到严重的困难，无法理解语音。目前未知这些人的言语缺陷的神经生物学基础，这限制了对听力障碍的评估和靶向治疗。 传出的听觉系统是听觉神经系统的划分，据信它可以微调和过滤听觉信息，因为它从内耳升至大脑。该系统已在动物中进行了广泛的研究，但是对于在噪音处理过程中人类的工作方式知之甚少。一些证据表明，传出的听觉系统中的选择性功能障碍可能会导致噪音的严重难以听力，同时使听力敏感性完好无损。 拟议的研究调查了人类传出听觉系统的一种特定机制，即内侧橄榄石（MOC）束，在正常听力的成人和儿童中对语音中的神经编码和感知。 MOC束是一种传出的神经回路，已显示可过滤和抑制动物内耳水平的背景噪声。该过滤器可能会使更少的噪声转录为神经代码，从而改善了在竞争背景噪声中对听觉信号的感知。目前尚不清楚人类MOC反射是否是：a）一种重要的传出机制，可降低噪声对语音自下而上的神经编码的影响，b）受自上而下的过程（例如主动聆听）调节以增强噪声的听力。 这些问题将在两项研究中解决。第一项研究将涉及在MOC反射激活过程中测量来自听觉神经和脑干的言语引起的神经活动，以确定这种反射是否改善了语音中噪声的神经编码。假设MOC反射的激活将改善在听觉神经和脑干水平上语音中的神经编码。在第二项研究中，参与者将积极地倾听听觉弹奏任务，而MOC反射则参与以确定认知需求是否在调节MOC反射。可以假设，听觉Stroop任务的更具挑战性的听力条件将对MOC反射强度产生更大的影响，表明大脑与内耳之间的调节关系。这项研究的结果阐明了传出系统在语音中的处理中的作用，可用于为有严重困难的人理解语音中的人进行有针对性的治疗和客观评估。