Temporal Effects in Forward Masking, Suppression, and Simultaneous Masking

描述(申请人提供)：人类能够在很大范围内听到声音，无论是在安静的环境中还是在存在背景噪音的情况下。当有持续的声音时，听觉系统可以通过降低其反应来实现这种广泛的动态范围。尽管有生理学证据表明耳蜗会有一个反馈环，以特定频率的方式调节增益。在同步掩蔽中测量到了时间效应，这与声音刺激导致的增益下降是一致的。目前尚不清楚这些时间效应是否源于反馈系统的处理。这项拟议的研究根据最近关于外周听觉系统的证据来研究这个重要的问题。这些实验被设计成在有或没有预先设计用于激活传出系统的声刺激的情况下，可以估计耳蜗中的两种增益指标--输入-输出函数和频率选择性。听力正常的听众和轻度耳蜗性听力损失的听众将在实验中接受测试。听力受损的听众提供了一种有趣的控制情况，在这种情况下，某些频道的增益已经永久性地降低。这些数据将在建立良好的基于生理的外围听觉系统模型中进行分析，以确定时间效应是否与被刺激的听觉通道内的增益下降一致。这项研究对于我们理解正常听力的基本听觉加工过程以及耳蜗性听力障碍的影响具有重要意义。听力正常的听者可能有一种类型的自动增益控制，它在耳蜗内数千个听觉通道中的每一个中独立工作。这种增益控制可以通过提高通道内的信噪比以及通过降低仅包含噪声的通道来帮助在背景噪声中感知语音。这一机制的丧失可能有助于解释为什么患有耳蜗性听力障碍的听者在背景噪音中会有特殊的问题。这项研究可能会提出新的处理策略，可能会被用于助听器和人工耳蜗，以改善在背景噪声中的感知。这项拟议的研究检验了一种假设，即听力正常的听者可能具有一种类型的自动增益控制，该类型的自动增益控制在耳蜗内数千个听觉通道中的每个通道上独立工作。这种增益控制可以通过提高通道内的信噪比以及通过降低仅包含噪声的通道来帮助在背景噪声中感知语音。这一机制的丧失可能有助于解释为什么患有耳蜗性听力障碍的听者在背景噪音中会有特殊的问题。这项研究可能会提出新的处理策略，可能会用于助听器和人工耳蜗，以改善对背景噪音的感知。

DESCRIPTION (provided by applicant): Humans are able to hear across a wide range of sound levels, both in quiet and in the presence of background noise. The auditory system may achieve this wide dynamic range by turning down its response when there is ongoing sound. Though there is physiological evidence for a feedback loop to the cochlea which adjusts gain in a frequency-specific manner. Temporal effects have been measured in simultaneous masking which would be consistent with a decrease in gain with sound stimulation. It is not clear whether these temporal effects are due to the processing of the feedback system. The proposed research examines this important question in light of more recent evidence about the peripheral auditory system. The experiments are designed so that two measures of gain in the cochlea, input-output functions and frequency selectivity, may be estimated with and without preceding acoustic stimulation designed to activate the efferent system. Listeners with normal hearing and listeners with mild cochlear hearing loss will be tested in the experiments. The hearing-impaired listeners provide an interesting control case in which the gain in some frequency channels has been permanently decreased. The data will be analyzed within a well-established physiologically-based model of the peripheral auditory system, to determine whether temporal effects are consistent with a decrease in gain within the auditory channel which is stimulated. This research is important to our understanding of basic auditory processing in normal hearing, and the effects of cochlear hearing impairment. Listeners with normal hearing may have a type of automatic gain control that works independently in each of the thousands of auditory channels in the cochlea. This gain control could help in the perception of speech in background noise, by improving the signal-to-noise ratio within a channel, and by turning down channels containing only noise. The loss of this mechanism could help explain why listeners with cochlear hearing impairment have particular problems in background noise. This research could suggest novel processing strategies that might be used in hearing aids and cochlear implants to improve perception in background noise.The proposed research examines the hypothesis that listeners with normal hearing may have a type of automatic gain control that works independently in each of the thousands of auditory channels in the cochlea. This gain control could help in the perception of speech in background noise, by improving the signal-to-noise ratio within a channel, and by turning down channels containing only noise. The loss of this mechanism could help explain why listeners with cochlear hearing impairment have particular problems in background noise. This research could suggest novel processing strategies that might be used in hearing aids and cochlear implants to improve perception in background noise.