Acoustic landmarks drive delta-theta oscillations to enable speech comprehension by facilitating perceptual parsing.
Acoustic landmarks drive delta-theta oscillations to enable speech comprehension by facilitating perceptual parsing.
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DOI：
10.1016/j.neuroimage.2013.06.035
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发表时间：
2014-01-15
期刊：
影响因子：
5.7
通讯作者：
Poeppel, David
中科院分区：
文献类型：
--
作者：
Doelling, Keith B.;Arnal, Luc H.;Ghitza, Oded;Poeppel, David
越来越多的研究表明，听觉皮层内固有的神经元慢振荡（< 10赫兹）似乎跟踪传入的语音和其他频谱-时间复杂的听觉信号。在这个框架内，最近的一些研究已经确定了临界频带时间包络作为这些振荡相位所反映的特定声学特征。然而，语音声学和神经振荡之间的这种一致性如何支撑可理解性尚不清楚。在这里，我们测试了一个假设，即临界频带包络中时间波动的“清晰度”作为语音音节率的时间线索，驱动delta-theta节奏来跟踪刺激并促进可理解性。我们将我们的发现解释为刺激中的尖锐事件导致皮层节奏重新排列并将刺激解析为音节大小的块以供进一步解码的证据。使用脑磁图记录，我们表明，通过消除时间波动，发生在音节率，包络跟踪活动减少。通过人为地恢复这些时间波动，包络追踪活动得以恢复。跟踪的这些变化与刺激的可理解性有关。综上所述，结果表明，刺激波动的剧烈程度，正如耳蜗输出所反映的那样，驱动振荡活动以音节速率跟踪和携带刺激。这个过程可能有助于将刺激解析成适合后续解码的有意义的块，从而增强感知和可理解性。
A growing body of research suggests that intrinsic neuronal slow (< 10 Hz) oscillations in auditory cortex appear to track incoming speech and other spectro-temporally complex auditory signals. Within this framework, several recent studies have identified critical-band temporal envelopes as the specific acoustic feature being reflected by the phase of these oscillations. However, how this alignment between speech acoustics and neural oscillations might underpin intelligibility is unclear. Here we test the hypothesis that the ‘sharpness’ of temporal fluctuations in the critical band envelope acts as a temporal cue to speech syllabic rate, driving delta-theta rhythms to track the stimulus and facilitate intelligibility. We interpret our findings as evidence that sharp events in the stimulus cause cortical rhythms to re-align and parse the stimulus into syllable-sized chunks for further decoding. Using magnetoencephalographic recordings, we show that by removing temporal fluctuations that occur at the syllabic rate, envelope-tracking activity is reduced. By artificially reinstating these temporal fluctuations, envelope-tracking activity is regained. These changes in tracking correlate with intelligibility of the stimulus. Together, the results suggest that the sharpness of fluctuations in the stimulus, as reflected in the cochlear output, drive oscillatory activity to track and entrain to the stimulus, at its syllabic rate. This process likely facilitates parsing of the stimulus into meaningful chunks appropriate for subsequent decoding, enhancing perception and intelligibility.
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影响因子：
25
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影响因子：
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影响因子：
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