Human frequency-following response: Representation of tonal sweeps
Human frequency-following response: Representation of tonal sweeps
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DOI：
10.1159/000013897
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发表时间：
2000-11-01
影响因子：
1.6
通讯作者：
Parkinson, J
中科院分区：
文献类型：
--
作者：
Krishnan, A;Parkinson, J
听觉神经单单位群体研究表明，相位锁定在稳态语音的神经编码中起主导作用。最近，我们报告说，锁相活动背后的人类频率跟随响应（FFR）也可以编码的前两个共振峰的几个音调近似稳态元音。由于听觉神经单单位群体研究还表明，锁相用于表示时变的语音样声音，因此推断人类FFR下的锁相神经活动同样是动态的，足以表示时变的声音。在95、85、75和65 dB nHL下，从8名听力正常的成年人中获得了升调和降调的FFR。结果清楚地表明，人体FFR确实遵循升调和降调的轨迹。此外，血流储备分数的振幅变化支持神经锁相随频率增加而降低的观点。最后，与上升音相比，下降音的血流储备分数幅度相对较小，这进一步支持了上升音比下降音产生更大的神经同步性的观点。这些结果表明，人类FFR可用于评估时变语音声音（如双元音和某些辅音-元音音节）的编码。版权所有（C）2000 S. Karger AG，巴塞尔。
Auditory nerve single-unit population studies have demonstrated that phase locking plays a dominant role in the neural encoding of steady-state speech sounds. Recently, we have reported that the phase-locked activity underlying the human frequency-following response (FFR) could also encode the first two formants of several tonal approximations of steady-state vowels. Since auditory nerve single-unit population studies have also demonstrated that phase locking is used to represent time-varying speech-like sounds, it was reasoned that the phase-locked neural activity underlying the human FFR, likewise, is dynamic enough to represent time-varying sounds. FFRs to a rising and a falling tone were obtained from 8 normal-hearing adults at 95, 85, 75 and 65 dB nHL, Results clearly demonstrated that the human FFR does indeed follow the trajectory of the rising and falling tones. Also, amplitude changes in the FFR supported the view that neural phase locking decreases with increasing frequency. Finally, the relatively smaller FFR amplitude for the falling tone compared to its rising counterpart lends further support to the notion that rising tones produce greater neural synchrony than falling tones. These results indicate that the human FFR may be used to evaluate encoding of time-varying speech sounds like diphthongs and certain consonant-vowel syllables. Copyright (C) 2000 S. Karger AG, Basel.