Carlyon Robert P, Mahendran Suresh, Deeks John M, Long Christopher J, Axon Patrick, Baguley David, Bleeck Stefan, Winter Ian M
MRC Cognition & Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom.
J Acoust Soc Am. 2008 Feb;123(2):973-85. doi: 10.1121/1.2821986.
In the "4-6" condition of experiment 1, normal-hearing (NH) listeners compared the pitch of a bandpass-filtered pulse train, whose inter-pulse intervals (IPIs) alternated between 4 and 6 ms, to that of isochronous pulse trains. Consistent with previous results obtained at a lower signal level, the pitch of the 4-6 stimulus corresponded to that of an isochronous pulse train having a period of 5.7 ms-longer than the mean IPI of 5 ms. In other conditions the IPI alternated between 3.5-5.5 and 4.5-6.5 ms. Experiment 2 was similar but presented electric pulse trains to one channel of a cochlear implant. In both cases, as overall IPI increased, the pitch of the alternating-interval stimulus approached that of an isochronous train having a period equal to the mean IPI. Experiment 3 measured compound action potentials (CAPs) to alternating-interval stimuli in guinea pigs and in NH listeners. The CAPs to pulses occurring after 4-ms intervals were smaller than responses to pulses occurring after 6-ms intervals, resulting in a modulated pattern that was independent of overall level. The results are compared to the predictions of a simple model incorporating auditory-nerve (AN) refractoriness, and where pitch is estimated from first-order intervals in the AN response.
在实验1的“4-6”条件下，听力正常（NH）的受试者将带通滤波脉冲串（其脉冲间隔[IPI]在4和6毫秒之间交替）的音高与等时脉冲串的音高进行比较。与在较低信号水平下获得的先前结果一致，4-6刺激的音高对应于周期为5.7毫秒的等时脉冲串的音高——比平均IPI的5毫秒长。在其他条件下，IPI在3.5-5.5和4.5-6.5毫秒之间交替。实验2与之类似，但向人工耳蜗的一个通道呈现电脉冲串。在这两种情况下，随着整体IPI增加，交替间隔刺激的音高接近周期等于平均IPI的等时序列的音高。实验3测量了豚鼠和听力正常受试者对交替间隔刺激的复合动作电位（CAP）。对4毫秒间隔后出现的脉冲的CAP小于对6毫秒间隔后出现的脉冲的反应，从而产生一种与整体水平无关的调制模式。将结果与包含听觉神经（AN）不应期且从AN反应的一阶间隔估计音高的简单模型的预测进行比较。
