DYNAMIC PROCESSES IN THE AUDITORY SYSTEM

听觉系统的动态过程

• 批准号: 2422424
• 负责人: ELIZABETH A STRICKLAND
• 金额: $ 5.18万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2422424
• 关键词: audiometry; auditory stimulus; auditory threshold; clinical research; hearing; human subject; noise; perceptual maskings; psychoacoustics; sound frequency

A fundamental property of the auditory system is the ability to follow changes in amplitude and frequency over time. Although we understand a good deal about static properties of the auditory system, the dynamic properties, although extensively researched, are less well understood. There is evidence that the sensitivity and tuning of the auditory system may change as a function of prior stimulation. Experiments on the temporal development of auditory filtering have shown that turning appears to be sharper for a signal presented with a delay after masker onset, relative to a signal presented at masker onset. Evidence that both sensitivity and tuning may change comes from a phenomenon called overshoot. Under certain conditions of frequency and level, the threshold for the tone is higher on the onset of the masker than it is after a delay of 100 ms or more. One of the most commonly proposed mechanisms for overshoot is that it reflects short-term neural adaptation. Some recent evidence suggests that this 'adaptation' is not simple fatigue at the signal frequency, but may be mediated by a neural feedback (or efferent) loop in the auditory system. This would explain the fact that frequencies remote from the signal frequency are at least partially responsible for the overshoot effect. This evidence and other research suggest that the effects underlying overshoot may provide a window on the relationship between active cochlear filtering and the efferent system. Although change in filter shape by itself cannot account for the magnitude of the overshoot effect, using an overshoot-type paradigm would allow examination of adaptation ad auditory filtershape independently. Auditory filter shapes have not been directly measured under the same conditions present in overshoot. This project proposes to measure overshoot and auditory filter shapes I similar conditions, and determine whether auditory filter shapes appear to narrow with stimulation under conditions in which overshoot is seen, and not in conditions in which overshoot is not seen. This has implications for understanding of the active process in normal hearing and for the effects of hearing impairment.

听觉系统的基本属性是遵循的能力 幅度和频率随时间的变化。 虽然我们 了解有关听觉系统的静态属性的很多交易， 动态特性虽然进行了广泛的研究，但效果不佳 理解。 有证据表明听觉的敏感性和调整 系统可能会随着先前刺激的函数而变化。 实验 关于听觉过滤的时间开发，表明 转弯似乎很清晰 遮罩发作，相对于在掩蔽发作处呈现的信号。 敏感性和调整可能都会改变的证据来自 现象称为过冲。 在某些频率条件下 和级别，音调的阈值较高 屏蔽器比延迟100毫秒或以上之后。 最大的 通常提出的过冲的机制是反映 短期神经适应。 最近的一些证据表明这一点 “适应”在信号频率下不是简单的疲劳，但可能是 通过听觉中的神经反馈（或传出）循环介导 系统。 这将解释一个事实，即频率远离 信号频率至少是部分负责的 影响。 这一证据和其他研究表明，造成的影响 超冲程可能会提供有关活动之间关系的窗口 耳蜗过滤和传出系统。 虽然过滤器的变化 形状本身无法解释过冲的大小 效果，使用过度型式范式将允许检查 适应广告听觉滤波器独立过滤。 听觉过滤器 在相同条件下尚未直接测量形状 出现在过冲。 该项目建议衡量过冲的 和听觉过滤器塑造了我类似条件，并确定是否 听觉过滤器形状似乎随着刺激而变窄 看到过度施加的条件，而不是在 看不见过冲。 这对理解 正常听力和听力的影响 损害。