DYNAMIC PROCESSES IN THE AUDITORY SYSTEM

听觉系统的一个基本特性是跟随 振幅和频率随时间的变化。 虽然我们 对听觉系统的静态特性有很好的了解， 动力学特性虽然得到了广泛的研究，但还不太好 明白 有证据表明，听觉的灵敏度和调谐 系统可以作为先前刺激函数而改变。 实验 对听觉过滤的时间发展的研究表明， 转向似乎是尖锐的信号提出了延迟后， 掩蔽物起始，相对于掩蔽物起始时呈现的信号。 灵敏度和调谐都可能改变的证据来自于 这一现象称为超调。 在一定的频率条件下 第二天早上，一个人在院子里散步。 比延迟100 ms或更长时间后的掩蔽。 一个最 通常提出的过冲机制是，它反映了 短期神经适应 最近的一些证据表明， “适应”不是简单的信号频率疲劳，但可能是 由听觉中的神经反馈（或传出）回路介导 系统 这就可以解释，频率远离 信号频率至少部分地导致过冲 效果 这一证据和其他研究表明， 过冲可以提供关于有源和无源之间的关系的窗口 耳蜗滤波和传出系统。 虽然过滤器的变化 形状本身不能解释过冲的大小 效果，使用过冲型范例将允许检查 自适应和听觉滤波器独立形成。 听觉滤波器 在相同的条件下没有直接测量形状 存在过冲。 本项目建议测量超调量 和听觉滤波器形状I类似的条件，并确定是否 听觉滤波器的形状似乎随着 出现过冲的条件，而不是 没有看到过冲。 这对理解 正常听力的活动过程和听力的影响 损伤

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.