Medizinische Physik, Universität Oldenburg, 26111 Oldenburg, Germany.
J Acoust Soc Am. 2011 Jun;129(6):3856-72. doi: 10.1121/1.3585847.
The auditory system is sensitive to interaural timing disparities in the fine structure and the envelope of sounds, each contributing important cues for lateralization. In this study, psychophysical measurements were conducted with customized envelope waveforms in order to investigate the isolated effect of different segments of a periodic, ongoing envelope on lateralization. One envelope cycle was composed of the four segments attack flank, hold duration, decay flank, and pause duration, which were independently varied to customize the envelope waveform. The envelope waveforms were applied to a 4-kHz sinusoidal carrier, and just noticeable envelope interaural time differences were measured in six normal hearing subjects. The results indicate that attack durations and pause durations prior to the attack are the most important stimulus characteristics for processing envelope timing disparities. The results were compared to predictions of three binaural lateralization models based on the normalized cross correlation coefficient. Two of the models included an additional stage to mimic neural adaptation prior to binaural interaction, involving either a single short time constant (5 ms) or a combination of five time constants up to 500 ms. It was shown that the model with the single short time constant accounted best for the data.
听觉系统对声音的精细结构和包络的两耳时间差异敏感，每个差异都为侧向定位提供了重要线索。在这项研究中，使用定制的包络波形进行心理物理测量，以研究周期性持续包络的不同段对侧向定位的单独影响。一个包络周期由四个段组成：起始边、保持持续时间、衰减边和暂停持续时间，它们可以独立变化以定制包络波形。将包络波形应用于 4 kHz 正弦载波，并在六个正常听力受试者中测量到可察觉的包络时间差。结果表明，起始边之前的起始持续时间和暂停持续时间是处理包络时间差异的最重要刺激特征。将结果与基于归一化互相关系数的三种双耳侧向定位模型的预测进行了比较。其中两个模型在双耳相互作用之前增加了一个阶段来模拟神经适应，涉及单个短时间常数（5 ms）或多达 500 ms 的五个时间常数的组合。结果表明，具有单个短时间常数的模型最能解释数据。
