The human auditory cortex was recently found to contribute to the frequency following response (FFR) and the cortical component has been shown to be more relevant to speech perception. However, it is not clear how cortical FFR may contribute to the processing of speech fundamental frequency (F0) and the dynamic pitch. Using intracranial EEG recordings, we observed a significant FFR at the fundamental frequency (F0) for both speech and speech-like harmonic complex stimuli in the human auditory cortex, even in the missing fundamental condition. Both the spectral amplitude and phase coherence of the cortical FFR showed a significant harmonic preference, and attenuated from the primary auditory cortex to the surrounding associative auditory cortex. The phase coherence of the speech FFR was found significantly higher than that of the harmonic complex stimuli, especially in the left hemisphere, showing a high timing fidelity of the cortical FFR in tracking dynamic F0 in speech. Spectrally, the frequency band of the cortical FFR was largely overlapped with the range of the human vocal pitch. Taken together, our study parsed the intrinsic properties of the cortical FFR and revealed a preference for speech-like sounds, supporting its potential role in processing speech intonation and lexical tones.

中文翻译：

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人类听觉皮层中的语音频率跟随反应不仅仅是一种简单的跟踪

最近发现人类听觉皮层对频率跟随响应 (FFR) 有贡献，并且皮层成分已被证明与语音感知更相关。然而，尚不清楚皮质 FFR 如何对语音基频 (F0) 和动态音高的处理做出贡献。使用颅内 EEG 记录，我们观察到人类听觉皮层中语音和类似语音的谐波复合刺激的基本频率 (F0) 的显着 FFR，即使在缺少基本条件的情况下也是如此。皮质 FFR 的频谱幅度和相位相干性均表现出显着的谐波偏好，并从初级听觉皮层衰减到周围的联想听觉皮层。发现语音 FFR 的相位相干性显着高于谐波复合刺激的相位相干性，尤其是在左半球，表明皮质 FFR 在跟踪语音动态 F0 时具有高时序保真度。从光谱上讲，皮质 FFR 的频带与人类声调的范围在很大程度上重叠。总之，我们的研究解析了皮质 FFR 的内在特性，并揭示了对类似语音的声音的偏好，支持其在处理语音语调和词汇音调方面的潜在作用。