Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, New York, 10032, USA.
J Neurosci. 2013 Jan 23;33(4):1417-26. doi: 10.1523/JNEUROSCI.3675-12.2013.
Our ability to selectively attend to one auditory signal amid competing input streams, epitomized by the "Cocktail Party" problem, continues to stimulate research from various approaches. How this demanding perceptual feat is achieved from a neural systems perspective remains unclear and controversial. It is well established that neural responses to attended stimuli are enhanced compared with responses to ignored ones, but responses to ignored stimuli are nonetheless highly significant, leading to interference in performance. We investigated whether congruent visual input of an attended speaker enhances cortical selectivity in auditory cortex, leading to diminished representation of ignored stimuli. We recorded magnetoencephalographic signals from human participants as they attended to segments of natural continuous speech. Using two complementary methods of quantifying the neural response to speech, we found that viewing a speaker's face enhances the capacity of auditory cortex to track the temporal speech envelope of that speaker. This mechanism was most effective in a Cocktail Party setting, promoting preferential tracking of the attended speaker, whereas without visual input no significant attentional modulation was observed. These neurophysiological results underscore the importance of visual input in resolving perceptual ambiguity in a noisy environment. Since visual cues in speech precede the associated auditory signals, they likely serve a predictive role in facilitating auditory processing of speech, perhaps by directing attentional resources to appropriate points in time when to-be-attended acoustic input is expected to arrive.
我们能够从竞争的输入流中选择性地关注一个听觉信号，这一能力以“鸡尾酒会”问题为代表，继续激发着来自不同方法的研究。从神经系统的角度来看，这种高要求的感知能力是如何实现的，目前仍不清楚且存在争议。已经证实，与忽略的刺激相比，对关注的刺激的神经反应得到了增强，但对忽略的刺激的反应仍然非常显著，导致了性能的干扰。我们研究了被关注的说话者的一致的视觉输入是否会增强听觉皮层的皮层选择性，从而减少对忽略的刺激的表示。我们记录了人类参与者在聆听自然连续语音时的脑磁图信号。使用两种定量言语神经反应的互补方法，我们发现，观看说话者的脸会增强听觉皮层跟踪该说话者的时间言语包络的能力。这种机制在鸡尾酒会环境中最为有效，促进了对关注的说话者的优先跟踪，而没有视觉输入时则观察不到显著的注意力调节。这些神经生理学结果强调了视觉输入在嘈杂环境中解决感知歧义的重要性。由于言语中的视觉线索先于相关的听觉信号，它们可能在促进言语的听觉处理中起到预测作用，也许是通过将注意力资源引导到预期听觉输入到达的适当时间点。
