Diesch E, Luce T
Institute of Psychology, Technical University of Berlin, Germany.
Psychophysiology. 1997 Sep;34(5):501-10. doi: 10.1111/j.1469-8986.1997.tb01736.x.
A long-latency response component (N1m) and the sustained field (SF) of the auditory evoked magnetic field elicited by two composite stimuli (a two-tone combination and a two-formant vowel) and their individually presented components (a 600-Hz and a 2100-Hz pure tone and two single-vowel formants with formant frequencies matched to the tone frequencies) were recorded using a 37-channel magnetometer. The response to the composite stimuli differed from the linear sum of the responses to the respective components in latency, equivalent dipole moment, and equivalent dipole location, suggesting an interaction among the processes elicited by the constituents of composite stimuli. N1m and SF source locations were more medial for the response to the high tone than to the low tone and more medial for the response to the high vowel formant than to the low vowel formant. The N1m formant sources were more lateral than the N1m tone sources. These findings suggest that, at the level of the auditory cortex, vowels are represented in terms of both the spectral pitches determined by their most prominent harmonics and, within the latency range of the N1m, the virtual pitch determined by the spacing of the harmonics.
使用37通道磁力计记录了由两种复合刺激（双音组合和双共振峰元音）及其单独呈现的成分（600赫兹和2100赫兹纯音以及共振峰频率与音调频率匹配的两个单元音共振峰）诱发的听觉诱发磁场的长潜伏期响应成分（N1m）和持续场（SF）。对复合刺激的响应在潜伏期、等效偶极矩和等效偶极位置上与对各个成分的响应的线性总和不同，这表明复合刺激成分引发的过程之间存在相互作用。对于高音调的响应，N1m和SF源位置比低音调更靠内侧，对于高元音共振峰的响应比低元音共振峰更靠内侧。N1m共振峰源比N1m音调源更靠外侧。这些发现表明，在听觉皮层水平，元音既通过其最突出谐波确定的频谱音高来表示，也在N1m的潜伏期范围内通过谐波间距确定的虚拟音高来表示。
