Temporal effects in forward masking, suppression, and simultaneous masking

 描述（由申请人提供）：人类能够在安静和存在背景噪声的情况下听到各种声级。听觉系统可以通过在存在持续声音时调低其响应来实现这种宽动态范围。虽然有生理学证据表明耳蜗的反馈回路以特定频率的方式调节增益，但其在人类行为中的功能尚未得到很好的理解。时间效应已在同时掩蔽中测量，这与声音刺激的放大（增益）减少一致。目前尚不清楚这些时间效应是否是由于反馈系统的处理。拟议中的研究将根据最近关于外周听觉系统的证据来探讨这一重要问题。实验被设计成使得与耳蜗中的增益、输入-输出功能和抑制相关的测量可以在有和没有被设计成激活反馈系统的先前声学刺激的情况下被估计。听力正常的听众和轻度耳蜗听力损失的听众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情况下，在某些频率通道的放大已经永久降低。将在基于生理学的外周听觉系统模型内分析数据，以确定时间效应是否与刺激的听觉通道内的增益降低一致。本研究对我们了解正常人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。听力正常的听众可能有一种自动放大控制，在耳蜗中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改善通道内的信噪比以及通过调低仅包含噪声的通道来帮助在背景噪声中感知语音。这一机制的丧失有助于解释为什么耳蜗听力障碍的听众在背景噪音中有特殊的问题。这项研究可能会提出新的处理策略，可用于助听器和人工耳蜗植入，以改善在背景噪声中的感知。

 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. Although there is physiological evidence for a feedback loop to the cochlea which adjusts gain in a frequency-specific manner, its function in human behavior is not well understood. Temporal effects have been measured in simultaneous masking which would be consistent with a decrease in amplification (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 measures related to gain in the cochlea, input-output functions and suppression, may be estimated with and without preceding acoustic stimulation designed to activate the feedback 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 amplification 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 amplification 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.