Neural mechanisms of sound intensity coding

声强编码的神经机制

• 批准号: 9294998
• 负责人: KATRINA M MACLEOD
• 金额: $ 31.42万
• 依托单位: UNIV OF MARYLAND, COLLEGE PARK
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9294998
• 关键词: Acoustic Nerve; Acoustic Stimulation; Acoustics; Action Potentials; Auditory; Behavioral; Binaural; Biological Models; Birds; Brain; Brain Stem; Cell Nucleus; Cell physiology; Cells; Cochlear Implants; Cochlear nucleus; Code; Complex; Computer Simulation; Cues; Data; Development; Devices; Disease; Elements; Environment; Feedback; Funding; Glycine; Hearing; Human; In Vitro; Intervention; Ion Channel; Lead; Measures; Modeling; Nerve; Nerve Fibers; Neuraxis; Neurons; Neuropathy; Noise; Pathway interactions; Pattern; Perception; Physiological; Physiology; Play; Population; Presbycusis; Process; Property; Prosthesis; Research; Role; Second Messenger Systems; Signal Transduction; Slice; Sodium; Sodium Channel; Speech; Stimulus; Synapses; Synaptic plasticity; Testing; Translating; Voltage-Gated Potassium Channel; Weight; auditory pathway; base; cooking; experimental study; gamma-Aminobutyric Acid; hearing impairment; in vivo; insight; neuromechanism; neurophysiology; patch clamp; relating to nervous system; restoration; sound; statistics; transmission process; voltage clamp

Project Summary. A detailed understanding of the neurophysiological basis of hearing is fundamental to the understanding of human hearing impairment and the guidance of further development of the most successful prosthetic intervention to date, the cochlear implant. Yet we still lack a complete description of how sound information is processed at even the first central nervous system relay, the cochlear nucleus. Our experiments in the avian model system focus on the first central nervous system target of the auditory nerve, the cochlear nucleus angularis, which initiates the ascending pathways involved in localization using binaural sound level cues and spectrotemporal processing. Rapid adaptation is crucial for neural coding of complex sounds and scenes by implementing temporal filtering, dynamic range adaptation and generating noise-invariant signal representations. Dynamic range adaptation occurs when auditory neurons adjust their firing rate-level encoding depending on the statistics of the acoustic stimulation, shifting upward with louder sound distributions. Adaptive cellular processes such as short-term synaptic plasticity (activity-dependent alterations in synaptic weight), intrinsic firing rate adaptation (via ion channel inactivation or hyperpolarizing currents), and modulatory transmitter feedback via second messenger systems are all candidate mechanism for implementing intensity-related adaptation. Using a combination of in vitro physiology, modeling and in vivo recordings, we will investigate an intrinsic mechanism called threshold adaptation and its reliance on the inactivation of sodium channels. We also test the hypothesis that short-term synaptic plasticity contributes to solving the `dynamic range problem': how human can hear across many orders of intensity magnitude in behavioral experiments given the (formerly known) limited physiological range of nerve fibers. Given the recent advances in the restoration of hearing using prosthetic devices that stimulate the auditory nerve, it is critical to understand how nerve activity is interpreted by the central nervous system. This research will provide new data on how acoustic information is transmitted from the auditory nerve to the first central relay in normal hearing, and thus can provide a reference for devices such as cochlear implants that stimulate the nerve directly. The emphasis on temporal envelope coding may also provide new information on disorders that may be related to disrupted temporal processing, such as age-related hearing loss or auditory neuropathy, which can lead to a common but disabling difficulty with understanding speech in noise.

项目摘要。 详细了解听觉的神经生理学基础是 了解人类听力障碍，并指导进一步发展的最 成功的人工干预，耳蜗植入。然而，我们仍然缺乏一个完整的描述 声音信息是如何在第一个中枢神经系统中继器耳蜗核中处理的。 我们在鸟类模型系统中的实验集中在第一个中枢神经系统靶点， 听觉神经，耳蜗角状核，它启动了参与 使用双耳声级线索和频谱时间处理进行定位。 快速适应对于复杂声音和场景的神经编码至关重要， 时间滤波、动态范围自适应和生成噪声不变信号表示。 动态范围适应发生在听觉神经元调整其放电率-水平编码时 取决于声学刺激的统计，随着更大的声音分布向上移动。 适应性细胞过程，如短期突触可塑性（活动依赖性改变， 突触重量），内在放电率适应（通过离子通道失活或超极化电流）， 和通过第二信使系统的调节性发射器反馈都是候选机制， 实施强度相关适应。使用体外生理学、建模和 体内记录，我们将研究一种称为阈值适应的内在机制及其对 钠离子通道的失活。我们还检验了短期突触可塑性 有助于解决“动态范围问题”：人类如何能够听到许多强度级别的声音 考虑到（以前已知的）有限的神经生理范围， 纤维 鉴于最近在使用刺激听觉的假肢装置恢复听力方面的进展， 听觉神经，了解中枢神经系统如何解释神经活动是至关重要的。 这项研究将提供关于声学信息如何从听觉神经传递到听觉神经的新数据。 第一个中央继电器在正常听力，从而可以提供一个参考的设备，如耳蜗 直接刺激神经的植入物对时间包络译码的强调还可提供 关于可能与时间处理中断有关的疾病的新信息，例如与年龄有关的 听力损失或听神经病，这可能导致一个常见的，但致残的困难， 在噪音中理解语言