Neural mechanisms supporting robust discrimination of spectrally and temporally degraded speech.
Neural mechanisms supporting robust discrimination of spectrally and temporally degraded speech.
复制标题
支持对频谱和时间退化语音进行稳健辨别的神经机制。
DOI：
10.1007/s10162-012-0328-1
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Kilgard,MichaelP
中科院分区：
文献类型：
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作者：
Ranasinghe,KamaliniG;Vrana,WilliamA;Matney,ChanelJ;Kilgard,MichaelP
尽管与正常耳蜗相比，耳蜗植入物传输的信息量非常有限，但它提供了良好的语音辨别能力。噪声声码语音，模拟耳蜗植入正常听力的听众，已经证明，频谱和时间退化的语音包含足够的线索，以提供准确的语音歧视。我们假设，在初级听觉皮层产生的神经活动模式的频谱和时间退化的语音声音将占强大的行为歧视的讲话。本实验研究了大鼠对噪声声码化辅音和元音的行为辨别，并记录了大鼠初级听觉皮层（A1）对相同声音的神经活动模式。我们报告的第一个证据的行为歧视退化语音的动物模型。我们的研究结果表明，大鼠能够准确地区分辅音和元音的声音，即使在显着的频谱和时间退化。老鼠可以忍受的退化程度与人类听众相当。我们观察到，基于A1神经元的时空模式（尖峰时间）的神经歧视与辅音的行为歧视高度相关，基于A1神经元的空间活动模式（尖峰计数）的神经歧视与元音的行为歧视高度相关。目前的研究结果表明，只要退化的声音产生不同的神经活动模式，语音识别就能抵抗退化。
Cochlear implants provide good speech discrimination ability despite highly limited amount of information they transmit compared with normal cochlea. Noise vocoded speech, simulating cochlear implants in normal hearing listeners, have demonstrated that spectrally and temporally degraded speech contains sufficient cues to provide accurate speech discrimination. We hypothesized that neural activity patterns generated in the primary auditory cortex by spectrally and temporally degraded speech sounds will account for the robust behavioral discrimination of speech. We examined the behavioral discrimination of noise vocoded consonants and vowels by rats and recorded neural activity patterns from rat primary auditory cortex (A1) for the same sounds. We report the first evidence of behavioral discrimination of degraded speech sounds by an animal model. Our results show that rats are able to accurately discriminate both consonant and vowel sounds even after significant spectral and temporal degradation. The degree of degradation that rats can tolerate is comparable to human listeners. We observed that neural discrimination based on spatiotemporal patterns (spike timing) of A1 neurons is highly correlated with behavioral discrimination of consonants and that neural discrimination based on spatial activity patterns (spike count) of A1 neurons is highly correlated with behavioral discrimination of vowels. The results of the current study indicate that speech discrimination is resistant to degradation as long as the degraded sounds generate distinct patterns of neural activity.