Effects of Noise on the Behavioral and Neural Categorization of Speech
Effects of Noise on the Behavioral and Neural Categorization of Speech
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DOI：
10.3389/fnins.2020.00153
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发表时间：
2020-02-27
影响因子：
4.3
通讯作者：
Boudreaux, Alex M.
中科院分区：
文献类型：
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作者：
Bidelman, Gavin M.;Bush, Lauren C.;Boudreaux, Alex M.
我们研究了言语的分类知觉（CP）是否也可能提供一种机制来帮助其在噪声中的知觉。我们改变了信噪比（SNR） [clear, 0 dB, -5 dB]，而听者将一个声学-语音连续体（/u/ to /a/）分类。噪声相关的行为分类变化仅在最低信噪比下观察到。事件相关脑电位（event - correlation brain potential, ERPs）通过P2波（类似于180 ~ 320 ms）区分类别与类别模糊的言语。在并行行为中，对于具有清晰语音状态（即连续端点）的语音的神经反应在低至-5 dB信噪比的噪声下具有鲁棒性，而对于模糊标记的反应则随着信噪比的降低而下降。结果表明，语音表征比相应的声学表征更能抵抗退化。研究结果表明，仅仅将语音分类的过程就提供了一种强大的机制，通过强化声学信号中的抽象类别，使语音代码更能抵抗外部干扰，从而帮助图像-背景语音感知。
We investigated whether the categorical perception (CP) of speech might also provide a mechanism that aids its perception in noise. We varied signal-to-noise ratio (SNR) [clear, 0 dB, -5 dB] while listeners classified an acoustic-phonetic continuum (/u/ to /a/). Noise-related changes in behavioral categorization were only observed at the lowest SNR. Event-related brain potentials (ERPs) differentiated category vs. category-ambiguous speech by the P2 wave (similar to 180-320 ms). Paralleling behavior, neural responses to speech with clear phonetic status (i.e., continuum endpoints) were robust to noise down to -5 dB SNR, whereas responses to ambiguous tokens declined with decreasing SNR. Results demonstrate that phonetic speech representations are more resistant to degradation than corresponding acoustic representations. Findings suggest the mere process of binning speech sounds into categories provides a robust mechanism to aid figure-ground speech perception by fortifying abstract categories from the acoustic signal and making the speech code more resistant to external interferences.