Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Hearing Research Laboratory, Samsung Medical Center, Seoul, South Korea.
Sci Rep. 2020 Sep 29;10(1):15973. doi: 10.1038/s41598-020-72714-z.
The temporal structure of sound such as in music and speech increases the efficiency of auditory processing by providing listeners with a predictable context. Musical meter is a good example of a sound structure that is temporally organized in a hierarchical manner, with recent studies showing that meter optimizes neural processing, particularly for sounds located at a higher metrical position or strong beat. Whereas enhanced cortical auditory processing at times of high metric strength has been studied, there is to date no direct evidence showing metrical modulation of subcortical processing. In this work, we examined the effect of meter on the subcortical encoding of sounds by measuring human auditory frequency-following responses to speech presented at four different metrical positions. Results show that neural encoding of the fundamental frequency of the vowel was enhanced at the strong beat, and also that the neural consistency of the vowel was the highest at the strong beat. When comparing musicians to non-musicians, musicians were found, at the strong beat, to selectively enhance the behaviorally relevant component of the speech sound, namely the formant frequency of the transient part. Our findings indicate that the meter of sound influences subcortical processing, and this metrical modulation differs depending on musical expertise.
声音的时间结构，如音乐和语音，通过为听众提供可预测的上下文，提高了听觉处理的效率。音乐节拍就是一个很好的例子，它的声音结构以分层的方式进行时间组织，最近的研究表明，节拍优化了神经处理，特别是对于位于较高节拍位置或强节拍的声音。虽然已经研究了在高节拍强度时增强的皮质听觉处理，但目前尚无直接证据表明节拍对皮质下处理有调制作用。在这项工作中，我们通过测量人类对在四个不同节拍位置呈现的语音的听觉频率跟随反应，研究了节拍对声音的皮质下编码的影响。结果表明，在强节拍处元音的基频的神经编码增强了，并且元音的神经一致性在强节拍处最高。在比较音乐家和非音乐家时，发现在强节拍处，音乐家选择性地增强了语音声音的与行为相关的成分，即瞬态部分的共振峰频率。我们的研究结果表明，声音的节拍会影响皮质下的处理，而且这种节拍调制取决于音乐专业知识。
