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。 详细了解听力的神经生理学基础对于听力的基础 了解人类听力障碍并指导最先进的技术进一步发展 迄今为止成功的假体干预，即人工耳蜗。然而我们仍然缺乏完整的描述 声音信息在第一个中枢神经系统中继站——耳蜗核中是如何处理的。 我们在鸟类模型系统中的实验集中于鸟类的第一个中枢神经系统目标 听神经，即耳蜗角核，它启动参与的上升通路 使用双耳声级提示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。 当听觉神经元调整其放电率水平编码时，就会发生动态范围适应 根据声学刺激的统计数据，随着声音分布更大而向上移动。 适应性细胞过程，例如短期突触可塑性（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）， 通过第二信使系统的调制发射机反馈都是候选机制 实施与强度相关的适应。结合体外生理学、建模和体内 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 钠通道失活。我们还测试了短期突触可塑性的假设 有助于解决“动态范围问题”：人类如何能够跨越多个强度等级听到声音 鉴于（以前已知的）神经生理范围有限，行为实验中的幅度 纤维。 鉴于最近使用刺激听力的假肢装置恢复听力方面取得了进展 听觉神经，了解中枢神经系统如何解释神经活动至关重要。 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。 正常听力的第一中枢中继，可为人工耳蜗等设备提供参考 直接刺激神经的植入物。对时间包络编码的强调还可以提供 有关可能与时间处理中断有关的疾病的新信息，例如与年龄相关的疾病 听力损失或听神经病变，这可能导致常见但致残的困难 理解噪声中的语音。