von Kriegstein K, Warren J D, Ives D T, Patterson R D, Griffiths T D
Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
Neuroimage. 2006 Aug 1;32(1):368-75. doi: 10.1016/j.neuroimage.2006.02.045. Epub 2006 Apr 27.
The length of a vocal tract is reflected in the sound it is producing. The length of the vocal tract is correlated with body size and humans are very good at making size judgments based on the acoustic effect of vocal tract length only. Here we investigate the underlying mechanism for processing this main auditory cue to size information in the human brain. Sensory encoding of the acoustic effect of vocal tract length (VTL) depends on a time-stabilized spectral scaling mechanism that is independent of glottal pulse rate (GPR, or voice pitch); we provide evidence that a potential neural correlate for such a mechanism exists in the medial geniculate body (MGB). The perception of the acoustic effect of speaker size is influenced by GPR suggesting an interaction between VTL and GPR processing; such an interaction occurs only at the level of non-primary auditory cortex in planum temporale and anterior superior temporal gyrus. Our findings support a two-stage model for the processing of size information in speech based on an initial stage of sensory analysis as early as MGB, and a neural correlate of the perception of source size in non-primary auditory cortex.
声道的长度反映在其发出的声音中。声道长度与身体大小相关，而且人类非常擅长仅根据声道长度的声学效应来进行大小判断。在此，我们探究人类大脑中处理这种关于大小信息的主要听觉线索的潜在机制。声道长度（VTL）的声学效应的感觉编码依赖于一种时间稳定的频谱缩放机制，该机制独立于声门脉冲率（GPR，即语音音高）；我们提供证据表明，内侧膝状体（MGB）中存在这种机制的潜在神经关联物。说话者大小的声学效应的感知受GPR影响，这表明VTL和GPR处理之间存在相互作用；这种相互作用仅发生在颞平面和颞上回前部的非初级听觉皮层水平。我们的研究结果支持一个两阶段模型，该模型用于处理语音中的大小信息，其基于最早在MGB进行的感觉分析初始阶段，以及非初级听觉皮层中源大小感知的神经关联物。
