Department of Psychology, University of Minnesota, 75 East River Rd, Minneapolis, MN, 55455, USA.
J Assoc Res Otolaryngol. 2009 Dec;10(4):595-607. doi: 10.1007/s10162-009-0180-0. Epub 2009 Jul 21.
Forward masking by harmonic tone complexes was measured for on- and off-frequency maskers as a function of masker phase curvature for two masker durations (30 and 200 ms). For the lowest signal frequency (1 kHz), the results matched predictions based on the expected interactions between the phase curvature and amplitude compression of peripheral auditory filtering. For the higher signal frequencies (2 and 6 kHz), the data increasingly departed from predictions in two respects. First, the effects of the masker phase curvature became stronger with increasing masker duration, inconsistent with the expected effects of the fast-acting compression and time-invariant phase response of basilar membrane filtering. Second, significant effects of masker phase curvature were observed for the off-frequency masker using a 6-kHz signal, inconsistent with predictions based on linear processing of stimuli well below the signal frequency. New predictions were generated assuming an additional effect with a longer time constant, consistent with the influence of medial olivocochlear efferent activation on otoacoustic emissions in humans. Reasonable agreement between the predicted and the measured effects suggests that efferent activation is a potential candidate mechanism to explain certain spectro-temporal masking effects in human hearing.
作为掩蔽器相位曲率的函数，测量了同频和频外掩蔽器的谐波复合音的前向掩蔽，掩蔽器持续时间为 30 和 200 毫秒。对于最低信号频率（1 kHz），结果与基于外周听觉滤波的相位曲率和幅度压缩之间预期相互作用的预测相匹配。对于更高的信号频率（2 和 6 kHz），数据在两个方面越来越偏离预测。首先，随着掩蔽器持续时间的增加，掩蔽器相位曲率的影响变得更强，这与基底膜滤波的快速作用压缩和时不变相位响应的预期影响不一致。其次，对于使用 6 kHz 信号的频外掩蔽器，观察到掩蔽器相位曲率的显著影响，这与基于低于信号频率的刺激的线性处理的预测不一致。假设存在具有更长时间常数的附加效应，生成了新的预测，这与人类中中橄榄耳蜗传出激活对耳声发射的影响一致。预测效果与测量效果之间的合理一致性表明，传出激活是解释人类听力中某些频谱-时间掩蔽效应的潜在候选机制。
