Rees A, Green G G, Kay R H
Hear Res. 1986;23(2):123-33. doi: 10.1016/0378-5955(86)90009-2.
Steady-state potentials evoked in response to binaural, sinusoidally amplitude-modulated (AM) pure tones and broadband noise signals were recorded differentially from position F4 and the ipsilateral mastoid on the human scalp. The responses elicited by the AM stimuli were approximately periodic waveforms whose energy was predominantly at the modulation frequency of the stimulus. The magnitude of responses was between 0.1 and 4 microV for modulation frequencies between 2 and 400 Hz imposed on a 1-kHz carrier signal. The magnitude of the responses increased linearly with log modulation depth for low (4 Hz) and high (80 Hz) modulation rates. The response magnitude also increased linearly with the mean intensity of the sound for intensities up to 60 dB above the subject's pure tone threshold; at higher levels the response saturated. The relationship between response magnitude and modulation frequency (the modulation transfer function) was a lowpass function for both pure tone and broadband noise carrier signals. The modulation transfer functions were similar to those obtained from human psychophysical measurements where spectral cues are either unavailable or not used by the subject. The responses also contained a significant component at the second harmonic of the modulation frequency. The magnitude of this component was greatest at modulation rates between 5 and 20 Hz. The responses elicited by ipsilateral and contralateral monaural stimulation were approximately equal in magnitude, and binaural stimulation produced a potential 30% greater than the individual monaural responses. It is suggested that the evoked response represents the entrained neural activity to temporal amplitude fluctuations, and reflects the psychophysically measured performance of the auditory system for the detection and analysis of amplitude modulation.
在人类头皮上，从F4位置和同侧乳突处差分记录了对双耳正弦调幅（AM）纯音和宽带噪声信号做出反应而诱发的稳态电位。AM刺激诱发的反应是近似周期性的波形，其能量主要集中在刺激的调制频率上。对于施加在1kHz载波信号上、调制频率在2至400Hz之间的情况，反应幅度在0.1至4微伏之间。对于低（4Hz）和高（80Hz）调制率，反应幅度随对数调制深度呈线性增加。对于强度高于受试者纯音阈值60dB的声音，反应幅度也随声音的平均强度呈线性增加；在更高强度时反应饱和。对于纯音和宽带噪声载波信号，反应幅度与调制频率之间的关系（调制传递函数）都是低通函数。这些调制传递函数与从人类心理物理学测量中获得的函数相似，在这些测量中，频谱线索要么不可用，要么受试者不使用。反应在调制频率的二次谐波处也包含一个显著成分。该成分的幅度在5至20Hz的调制率下最大。同侧和对侧单耳刺激诱发的反应幅度大致相等，双耳刺激产生的电位比单个单耳反应大30%。有人认为，诱发反应代表了对时间幅度波动的夹带神经活动，并反映了听觉系统在检测和分析幅度调制方面心理物理学测量的表现。
