Signal processing in the auditory periphery : relation to the cochlear delay

开始同步是一个重要的线索，知觉分组的声音作为一个单一的音调。然而，即使单个复杂音调的所有组成部分在物理上完全同时开始，它们的时间关系也可能无法在耳蜗水平上保留下来。耳蜗基底膜（BM）的硬度从基底侧（靠近卵圆窗）到耳蜗根尖侧逐渐降低。因此，低频分量引起的振动比高频分量引起的振动到达相应位置的时间要晚。这种现象被称为“耳蜗延迟”。我们进行了一系列的心理声学和生理实验来研究耳蜗延迟是否显著影响同步的知觉判断，以及听觉脑干反应（ABR）是否会随之改变。采用控制耳蜗延迟量的两种啁啾和脉冲作为实验刺激，探讨了耳蜗延迟是否会对两种声音的知觉同步性判断产生系统偏差。心理声学实验结果表明，当刺激引起内源性耳蜗延迟（脉冲）时，同步判断准确率最高。此外，引起增强的耳蜗延迟的刺激比消除耳蜗延迟的刺激的准确性更高。生理实验结果表明，人类听觉系统的时间加工具有非对称性。心理声学实验结果表明，当刺激引起内源性耳蜗延迟（脉冲）时，同步判断准确率最高。此外，引起增强的耳蜗延迟的刺激比消除耳蜗延迟的刺激的准确性更高。生理实验结果表明，人类听觉系统的时间加工具有非对称性。

Onset synchrony is an important cue for perceptual grouping of sounds as a single tone. However, even if all of the components of a single complex tone physically begin exactly simultaneously, their temporal relation might not be preserved at the cochlear level. The stiffness of the cochlear Basilar Membrane(BM) gradually decreases from the basal side(closer to the oval window) to the apical side. Therefore, the vibration caused by low-frequency components reaches its associated location later than that caused by high-frequency components. This phenomenon is referred to as "cochlear delay." We have performed a series of phychoacoustic and physiological experiments to investigate if the cochlear delay significantly affects the perceptual judgment of synchronization, and also if Auditory Brainstem Response(ABR) would change accordingly. Two types of chirps which were controlled the amount of cochlear delay and a pulse were used as experimental stimuli to investigate whether or not cochlear delay imposes a systematic bias on the judgment of perceptual synchrony of two sounds. The results of the psychoacoustic experiments showed that the synchrony judgment accuracy was highest for stimuli that evoke an intrinsic cochlear delay(pulse). Furthermore, accuracy was higher for stimuli that evoke enhanced cochlear delay than for stimuli that cancelled out cochlear delay. The results of the physiological experiments showed that there is an asymmetric aspect of temporal processing in the human auditory system.The results of the psychoacoustic experiments showed that the synchrony judgment accuracy was highest for stimuli that evoke an intrinsic cochlear delay(pulse). Furthermore, accuracy was higher for stimuli that evoke enhanced cochlear delay than for stimuli that cancelled out cochlear delay. The results of the physiological experiments showed that there is an asymmetric aspect of temporal processing in the human auditory system.