Attention Differentially Affects Acoustic and Phonetic Feature Encoding in a Multispeaker Environment.
Attention Differentially Affects Acoustic and Phonetic Feature Encoding in a Multispeaker Environment.
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DOI：
10.1523/jneurosci.1455-20.2021
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发表时间：
2022-01-26
期刊：
影响因子：
--
通讯作者：
Lalor EC
中科院分区：
文献类型：
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作者：
Teoh ES;Ahmed F;Lalor EC
人类有一种非凡的能力，可以选择性地把注意力集中在一群说话的人身上。这种现象背后的神经机制尚不完全清楚。特别是，长期以来一直存在关于注意力在语音处理层次结构中是处于早期还是晚期的争论。更好地理解这一点的一种方法是研究注意力如何不同地影响分层声学和语言语音表征的神经生理指标。在本研究中，我们通过使用编码模型来识别不同表征水平的语音处理的神经关联。具体来说，我们在“鸡尾酒会”注意力实验中记录了14名人类受试者（9名女性和5名男性）的脑电图。基于这些数据的模型比较揭示了语音特征处理的出席，而不是没有出席的语音。此外，我们表明，注意特别增强语音特征处理的孤立指标，但这种注意效应对于声学处理的孤立措施并不明显。这些结果为注意力对言语的不同词汇前表征的影响提供了新的见解，这些见解补充了最近关于出席演讲的分层编码的解剖学解释。此外，我们的研究结果支持这样一种观点，即对于出席演讲，语音特征被处理为一个不同的阶段，与语音声学的处理分开。在一个有很多说话人的环境中，人类非常善于把注意力集中在一个说话人身上。然而，大脑如何处理有旁听和无人旁听演讲的细节并不完全清楚。在这里，我们探讨了注意力如何影响语音的声学处理，以及这些声音到绝对语音特征的映射。我们发现了有旁听而非无旁听语音的绝对语音特征加工的证据。此外，我们发现有证据表明，注意可以增强语音特征加工，而听觉加工则不然。这些发现为我们理解人类大脑如何解决鸡尾酒会问题增加了一个重要的新层面。
Humans have the remarkable ability to selectively focus on a single talker in the midst of other competing talkers. The neural mechanisms that underlie this phenomenon remain incompletely understood. In particular, there has been longstanding debate over whether attention operates at an early or late stage in the speech processing hierarchy. One way to better understand this is to examine how attention might differentially affect neurophysiological indices of hierarchical acoustic and linguistic speech representations. In this study, we do this by using encoding models to identify neural correlates of speech processing at various levels of representation. Specifically, we recorded EEG from fourteen human subjects (nine female and five male) during a “cocktail party” attention experiment. Model comparisons based on these data revealed phonetic feature processing for attended, but not unattended speech. Furthermore, we show that attention specifically enhances isolated indices of phonetic feature processing, but that such attention effects are not apparent for isolated measures of acoustic processing. These results provide new insights into the effects of attention on different prelexical representations of speech, insights that complement recent anatomic accounts of the hierarchical encoding of attended speech. Furthermore, our findings support the notion that, for attended speech, phonetic features are processed as a distinct stage, separate from the processing of the speech acoustics. SIGNIFICANCE STATEMENT Humans are very good at paying attention to one speaker in an environment with multiple speakers. However, the details of how attended and unattended speech are processed differently by the brain is not completely clear. Here, we explore how attention affects the processing of the acoustic sounds of speech as well as the mapping of those sounds onto categorical phonetic features. We find evidence of categorical phonetic feature processing for attended, but not unattended speech. Furthermore, we find evidence that categorical phonetic feature processing is enhanced by attention, but acoustic processing is not. These findings add an important new layer in our understanding of how the human brain solves the cocktail party problem.