Temporal Effects in Forward Masking, Suppression, and Simultaneous Masking

描述（由申请人提供）：无论是在安静的环境中还是在有背景噪音的环境中，人类都能听到很宽范围的声音。当有持续的声音时，听觉系统可以通过降低其响应来实现这种宽动态范围。尽管有生理证据表明耳蜗有一个反馈回路，它以特定频率的方式调节增益。在同时掩蔽中测量了时间效应，这与声音刺激下增益的减少是一致的。目前尚不清楚这些时间效应是否由于反馈系统的处理。根据最近关于外周听觉系统的证据，提出的研究检查了这个重要的问题。实验的设计是为了在有或没有预先设计激活传出系统的声学刺激的情况下，可以估计耳蜗增益的两项测量，即输入-输出功能和频率选择性。听力正常的听者和轻度耳蜗听力损失的听者将在实验中进行测试。听力受损的听众提供了一个有趣的控制案例，其中某些频率通道的增益永久性地降低了。这些数据将在一个完善的基于生理的外周听觉系统模型中进行分析，以确定受刺激的听觉通道内的增益减少是否与时间效应一致。这项研究对我们了解正常听力的基本听觉加工以及耳蜗听力损伤的影响具有重要意义。听力正常的听众可能有一种自动增益控制，它在耳蜗中数千个听觉通道中的每个通道中独立工作。这种增益控制可以通过提高信道内的信噪比，并通过降低只包含噪声的信道，帮助在背景噪声中感知语音。这种机制的缺失可以帮助解释为什么有耳蜗听力障碍的听众在背景噪音中有特殊的问题。这项研究可能提出新的处理策略，可能用于助听器和人工耳蜗植入物，以提高对背景噪音的感知。这项提议的研究检验了一个假设，即听力正常的听者可能有一种自动增益控制，在耳蜗中数千个听觉通道中的每个通道中独立工作。这种增益控制可以通过提高信道内的信噪比，并通过降低只包含噪声的信道，帮助在背景噪声中感知语音。这种机制的缺失可以帮助解释为什么有耳蜗听力障碍的听众在背景噪音中有特殊的问题。这项研究可能提出新的处理策略，可能用于助听器和人工耳蜗植入物，以提高对背景噪音的感知。

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.