Gunji A, Hoshiyama M, Kakigi R
Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, 444-8585, Okazaki, Japan.
Clin Neurophysiol. 2001 Mar;112(3):514-20. doi: 10.1016/s1388-2457(01)00462-x.
We recorded vocalization-related cortical fields (VRCF) under complete masking of a subject's own voice to identify the auditory component evoked by a subject's own voice in the VRCF complex.
We recorded VRCF during simple vowel (/u/) vocalization in 10 right-handed healthy volunteers under two conditions: (1) no masking (control) and (2) masking of the subject's own voice by weighted-white noise during vocalization. In the second experiment, we recorded auditory evoked magnetic fields (AEF) following stimulation of a speech sound applied by voice-recorder.
The onset of VRCF appeared gradually before the vocalization onset, and a clear phase-reversed deflection was identified after the onset of vocalization. The difference waveform obtained by subtracting the VRCF of the masking condition from that of the control showed a deflection (1M) at 81.3+/-20.5 (mean+/-SD) ms after the onset of vocalization, but there was no consistent deflection before the vocalization onset. The AEF following voice sound in the second experiment showed the M100 component at 94.3+/-18.4 ms. The equivalent current dipole of the 1M component for different waveforms was located close in the auditory cortex to that of the M100 for AEF waveforms in each hemisphere.
We successfully separated the auditory feedback response from the VRCF complex, using an adequate masking condition during vocalization of a subject's own voice. The masking effect was crucial to the auditory feedback process after the onset of vocalization. The present results suggested that the 1M component was mainly generated from the auditory feedback process by the subject's own voice. The activated auditory area for simple own voice might be similar to that for simple external sound.
我们在完全掩盖受试者自身声音的情况下记录与发声相关的皮质区域（VRCF），以识别VRCF复合体中由受试者自身声音诱发的听觉成分。
我们在10名右利手健康志愿者进行简单元音（/u/）发声时，在两种条件下记录VRCF：（1）无掩蔽（对照）和（2）发声时用加权白噪声掩蔽受试者自身声音。在第二个实验中，我们记录了语音记录仪施加语音刺激后的听觉诱发磁场（AEF）。
VRCF的起始在发声起始之前逐渐出现，并且在发声起始后识别出明显的相位反转偏转。通过从对照条件的VRCF中减去掩蔽条件的VRCF获得的差异波形在发声起始后81.3±20.5（平均值±标准差）毫秒处显示出偏转（1M），但在发声起始之前没有一致的偏转。第二个实验中语音后的AEF在94.3±18.4毫秒处显示出M100成分。每个半球中不同波形的1M成分的等效电流偶极子在听觉皮层中的位置与AEF波形的M100的位置相近。
我们通过在受试者自身发声时使用适当的掩蔽条件，成功地从VRCF复合体中分离出听觉反馈反应。掩蔽效应对于发声起始后的听觉反馈过程至关重要。目前的结果表明，1M成分主要由受试者自身声音的听觉反馈过程产生。简单自身声音激活的听觉区域可能与简单外部声音的听觉区域相似。
