Vander Ghinst Marc, Bourguignon Mathieu, Op de Beeck Marc, Wens Vincent, Marty Brice, Hassid Sergio, Choufani Georges, Jousmäki Veikko, Hari Riitta, Van Bogaert Patrick, Goldman Serge, De Tiège Xavier
Laboratoire de Cartographie fonctionnelle du Cerveau, UNI-ULB Neuroscience Institute, Université libre de Bruxelles, 1070 Brussels, Belgium, Service d'ORL et de chirurgie cervico-faciale, ULB-Hôpital Erasme, Université libre de Bruxelles, 1070 Brussels, Belgium,
Laboratoire de Cartographie fonctionnelle du Cerveau, UNI-ULB Neuroscience Institute, Université libre de Bruxelles, 1070 Brussels, Belgium, Brain Research Unit, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, FI-00076-AALTO, Espoo, Finland, and BCBL, Basque Center on Cognition, Brain and Language, 20009 San Sebastian, Spain.
J Neurosci. 2016 Feb 3;36(5):1596-606. doi: 10.1523/JNEUROSCI.1730-15.2016.
Using a continuous listening task, we evaluated the coupling between the listener's cortical activity and the temporal envelopes of different sounds in a multitalker auditory scene using magnetoencephalography and corticovocal coherence analysis. Neuromagnetic signals were recorded from 20 right-handed healthy adult humans who listened to five different recorded stories (attended speech streams), one without any multitalker background (No noise) and four mixed with a "cocktail party" multitalker background noise at four signal-to-noise ratios (5, 0, -5, and -10 dB) to produce speech-in-noise mixtures, here referred to as Global scene. Coherence analysis revealed that the modulations of the attended speech stream, presented without multitalker background, were coupled at ∼0.5 Hz to the activity of both superior temporal gyri, whereas the modulations at 4-8 Hz were coupled to the activity of the right supratemporal auditory cortex. In cocktail party conditions, with the multitalker background noise, the coupling was at both frequencies stronger for the attended speech stream than for the unattended Multitalker background. The coupling strengths decreased as the Multitalker background increased. During the cocktail party conditions, the ∼0.5 Hz coupling became left-hemisphere dominant, compared with bilateral coupling without the multitalker background, whereas the 4-8 Hz coupling remained right-hemisphere lateralized in both conditions. The brain activity was not coupled to the multitalker background or to its individual talkers. The results highlight the key role of listener's left superior temporal gyri in extracting the slow ∼0.5 Hz modulations, likely reflecting the attended speech stream within a multitalker auditory scene.
When people listen to one person in a "cocktail party," their auditory cortex mainly follows the attended speech stream rather than the entire auditory scene. However, how the brain extracts the attended speech stream from the whole auditory scene and how increasing background noise corrupts this process is still debated. In this magnetoencephalography study, subjects had to attend a speech stream with or without multitalker background noise. Results argue for frequency-dependent cortical tracking mechanisms for the attended speech stream. The left superior temporal gyrus tracked the ∼0.5 Hz modulations of the attended speech stream only when the speech was embedded in multitalker background, whereas the right supratemporal auditory cortex tracked 4-8 Hz modulations during both noiseless and cocktail-party conditions.
我们使用连续听觉任务，通过脑磁图和皮质-发声相干分析，评估了在多说话者听觉场景中听众的皮质活动与不同声音的时间包络之间的耦合。从20名右利手健康成年人记录神经磁信号，他们收听五个不同的录制故事（关注的语音流），一个没有任何多说话者背景（无噪声），四个与“鸡尾酒会”多说话者背景噪声以四种信噪比（5、0、-5和-10 dB）混合以产生噪声中的语音混合物，这里称为全局场景。相干分析表明，在没有多说话者背景的情况下呈现的关注语音流的调制在约0.5 Hz与双侧颞上回的活动耦合，而4-8 Hz的调制与右侧颞上听觉皮层的活动耦合。在鸡尾酒会条件下，对于多说话者背景噪声，关注语音流在两个频率上的耦合都比未关注的多说话者背景更强。耦合强度随着多说话者背景增加而降低。在鸡尾酒会条件下，与没有多说话者背景时的双侧耦合相比，约0.5 Hz的耦合变为左半球主导，而4-8 Hz的耦合在两种条件下都保持右半球侧化。大脑活动与多说话者背景或其单个说话者没有耦合。结果突出了听众左颞上回在提取缓慢的约0.5 Hz调制中的关键作用，这可能反映了多说话者听觉场景中的关注语音流。
当人们在“鸡尾酒会”中听一个人说话时，他们的听觉皮层主要跟随关注的语音流而不是整个听觉场景。然而，大脑如何从整个听觉场景中提取关注的语音流以及背景噪声增加如何破坏这个过程仍存在争议。在这项脑磁图研究中，受试者必须收听有或没有多说话者背景噪声的语音流。结果支持了关注语音流的频率依赖性皮质跟踪机制。只有当语音嵌入多说话者背景时，左颞上回才跟踪关注语音流的约0.5 Hz调制，而右侧颞上听觉皮层在无噪声和鸡尾酒会条件下都跟踪4-8 Hz调制。
