Forward Masking of Amplitude Modulation

幅度调制的前向掩蔽

基本信息

批准号：
7035349
负责人：
MAGDALENA WOJTCZAK
金额：
$ 7.25万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-05-01 至 2007-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7035349
关键词：
auditory discrimination auditory stimulus auditory threshold behavioral /social science research tag clinical research hearing tests human subject neural information processing perceptual maskings sensory signal detection time perception

项目摘要

DESCRIPTION (provided by applicant): The proposed project focuses on the phenomenon of forward masking in the amplitude-modulation (AM) domain. This forward masking refers to a condition in which a well-detectable modulation (signal) is rendered undetectable by adding another modulation (masker) that precedes it in time. Forward masking in the modulation domain may critically affect the perception of speech and other complex stimuli encountered in daily listening situations. The proposed study will be the first to investigate this phenomenon which, because of its temporal characteristics, is different from AM adaptation. The experiments will use times of uninterrupted exposure to AM that are comparable to those present in everyday acoustic stimuli, such as speech. The study will investigate three important characteristics of the forward masking effect: 1) The time course of AM forward masking. The time necessary for the mechanism processing AM to recover to its maximum sensitivity will be estimated by measuring threshold for detecting the signal AM as a function of the delay between the masker and signal AM. 2) Tuning of the effect of AM forward masking. Modulation-rate selectivity of the forward masking effect will be assessed by measuring threshold for detecting the signal AM as a function of the modulation rate of the masker AM. 3) Spectral additivity of AM forward masking. The amounts of forward masking produced by two AM maskers combined together will be compared with the amounts of masking produced by each masker individually. These three experiments will provide information about the temporal and spectral extent to which interfering envelope fluctuations affect the detection of ensuing target fluctuations and about the integration of the effect across modulation rates. The data will establish a foundation for future collaborative work with auditory neurophysiologists with the long-term objective to identify the site and nature of the mechanism underlying AM forward masking and thus to expand knowledge about the mechanisms that process envelope modulations.

描述（由申请人提供）：拟议的项目着重于振幅调制（AM）域中正向掩蔽的现象。这种正向掩蔽是指通过添加另一个在及时之前的调制（屏蔽器）来渲染可检测到的调制（信号）的条件。调制域中的正向掩盖可能会严重影响言语和日常聆听情况下遇到的其他复杂刺激的感知。拟议的研究将是第一个研究这种现象的研究，由于其时间特征，它与AM适应性不同。这些实验将使用与日常声学刺激（例如语音）中存在的AM的不间断暴露时间。该研究将研究向前掩盖效应的三个重要特征：1）AM向前掩盖的时间过程。通过测量阈值检测信号AM作为掩盖器和信号AM之间的延迟的函数，将估计机理处理AM恢复至最大灵敏度所需的时间。 2）调整AM正向掩模的效果。通过测量阈值检测信号AM作为蒙版AM的调制速率的函数，将评估向前掩模效应的调制速率选择性。 3）AM正向掩蔽的频谱添加性。将两个AM遮罩器合并在一起产生的正向掩蔽量与每个掩蔽者单独产生的掩蔽量进行比较。这三个实验将提供有关干扰包络波动的时间和光谱范围的信息，影响了随后的目标波动的检测以及跨调制速率的效果的整合。该数据将为与听觉神经生理学家的未来合作工作建立基础，其长期目标是确定正向掩盖基础机制的位置和性质，从而扩大了有关处理信封调制机制的知识。