Right-hemisphere auditory cortex is dominant for coding syllable patterns in speech
Right-hemisphere auditory cortex is dominant for coding syllable patterns in speech
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DOI：
10.1523/jneurosci.0187-08.2008
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发表时间：
2008-04-09
影响因子：
5.3
通讯作者：
Kraus, Nina
中科院分区：
文献类型：
--
作者：
Abrams, Daniel A.;Nicol, Trent;Kraus, Nina
长期以来，语音的皮层分析一直被认为是左半球听觉区域的领域。最近的一个假说提出，包括语音在内的声信号的皮层处理是基于语音信号固有的成分速率进行双边介导的。为了支持这一假设，以前的研究表明，在非语音声学信号的慢时间特征（3-5 Hz）侧化到右半球的听觉区域，而快速的时间特征（20-50 Hz）侧化到左半球。这些结果是使用非言语刺激获得的，目前尚不清楚右半球听觉皮层是否在编码被称为言语包络的言语中的慢时间特征方面占主导地位。在这里，我们展示了强大的右半球优势编码的语音包络，这代表音节模式，是正常的语音感知的关键。与左半球相比，右半球听觉皮层在遵循语音包络的轮廓方面要准确100%，并且在遵循包络时的反应幅度要大33%。不对称性是明显的，无论耳朵的刺激，尽管优势的对侧连接在上升的听觉通路。结果提供的证据表明，右半球在语音处理中起着特定的和重要的作用，并支持这一假设，即语音的声学处理涉及到由右半球和左半球听觉皮层中的速率专门神经元组成的时间特征的信号的分解。
Cortical analysis of speech has long been considered the domain of left-hemisphere auditory areas. A recent hypothesis poses that cortical processing of acoustic signals, including speech, is mediated bilaterally based on the component rates inherent to the speech signal. In support of this hypothesis, previous studies have shown that slow temporal features (3-5 Hz) in nonspeech acoustic signals lateralize to right-hemisphere auditory areas, whereas rapid temporal features (20-50 Hz) lateralize to the left hemisphere. These results were obtained using nonspeech stimuli, and it is not known whether right-hemisphere auditory cortex is dominant for coding the slow temporal features in speech known as the speech envelope. Here we show strong right-hemisphere dominance for coding the speech envelope, which represents syllable patterns and is critical for normal speech perception. Right-hemisphere auditory cortex was 100% more accurate in following contours of the speech envelope and had a 33% larger response magnitude while following the envelope compared with the left hemisphere. Asymmetries were evident regardless of the ear of stimulation despite dominance of contralateral connections in ascending auditory pathways. Results provide evidence that the right hemisphere plays a specific and important role in speech processing and support the hypothesis that acoustic processing of speech involves the decomposition of the signal into constituent temporal features by rate-specialized neurons in right-and left-hemisphere auditory cortex.