Processing of complex sounds at high frequencies

摘要 音高是自然声音的基本感知维度，并且音高感知对于自然声音的产生至关重要。 理解语音和音乐，以及分离并发的声音。音高感知下降， 声音中的分量频率增加超过2-3 kHz，这一趋势通常被认为反映了 在2-3 kHz以上，听觉神经中的时间精细结构（TFS）的相位锁定的相应损失。 然而，最近的心理物理学和生理学的发现，包括证据表明，准确的音高感知 在较高频率下是可能的，而在较低频率下， 以前认为，他们对这种联系表示怀疑。拟议研究的目的1测试假设， 在跨频率比较或信息整合方面普遍存在缺陷，而不是相位滚降 锁定可以解释为什么音高感知随着频率的增加而降低。为此，性能将 在不依赖于跨频率比较的任务中测量，在这种情况下， 在低频和高频下的性能相当，并且在设计要求跨- 频率比较，其中该假设将预测在高频率下比在低频率下更差的性能。 低频拟议研究的目的2检验了这一假设，即这种赤字在跨频率 比较还可以预测并发声音的分离应该在高频处受损， 即使当分离提示没有经由TFS信息编码时也是如此。为此，我们将衡量 其中振幅调制和起始时间线索促进单个或多个靶的分离 从复杂的音调中提取成分。在这里，我们的假设预测，性能应该较差， 更高的频率，特别是当与不需要隔离的匹配控制任务相比时。的 行为结果，将借助模拟听神经的理想观察者分析进行解释 反应，将提供有价值的洞察神经机制，基础复杂的音高知觉， 并发声音隔离。

Abstract Pitch is a fundamental perceptual dimension of natural sounds, and pitch perception is crucial for understanding speech and music and for segregating concurrent sounds. Pitch perception degrades as component frequencies in a sound increase beyond 2-3 kHz, a trend that is usually assumed to reflect a corresponding loss of phase locking to temporal fine structure (TFS) in the auditory nerve above 2-3 kHz. However, recent psychophysical and physiological findings, including evidence that accurate pitch perception is possible at high frequencies and that phase locking may degrade in humans at lower frequencies than previously believed, have cast doubt on this link. Aim 1 of the proposed research tests the hypothesis that a general deficit in across-frequency comparison or integration of information, instead of the roll-off of phase locking, may explain why pitch perception degrades as frequency increases. To this end, performance will be measured in tasks that do not depend on across-frequency comparisons, where this hypothesis would predict equivalent performance at low and high frequencies, and in tasks that are designed to require across- frequency comparisons, where this hypothesis would predict poorer performance at high frequencies than at low frequencies. Aim 2 of the proposed research tests the hypothesis that this deficit in across-frequency comparison might also predict that segregation of concurrent sounds should be impaired at high frequencies, even when the segregation cues are not encoded via TFS information. To this end, we will measure the extent to which amplitude modulation and onset asynchrony cues promote segregation of single or multiple target components from within a complex tone. Here, our hypothesis predicts that performance should be poorer at high frequencies, especially when compared to matched control tasks that require no segregation. The behavioral results, which will be interpreted with the aid of ideal observer analysis of simulated auditory nerve responses, will provide valuable insight into the neural mechanisms that underlie complex pitch perception and concurrent sound segregation.