Visual Activation and Audiovisual Interactions in the Auditory Cortex during Speech Perception: Intracranial Recordings in Humans
Visual Activation and Audiovisual Interactions in the Auditory Cortex during Speech Perception: Intracranial Recordings in Humans
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DOI：
10.1523/jneurosci.2875-08.2008
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发表时间：
2008-12-24
影响因子：
5.3
通讯作者：
Giard, Marie-Helene
中科院分区：
文献类型：
--
作者：
Besle, Julien;Fischer, Catherine;Giard, Marie-Helene
血流动力学研究表明，听觉皮层可以被视觉唇运动激活，是听觉和视觉语音处理之间相互作用的场所。然而，他们没有提供关于这些跨模态过程的时序和机制的信息。我们记录了颅内事件相关电位的听觉，视觉，和双峰语音音节的深度电极植入在颞叶的10名癫痫患者（共932接触）。我们发现，嘴唇运动激活次级听觉区，视觉运动区MT/V5激活后不久（约10 ms）。在听觉皮层的这种puperous前馈视觉激活之后，视听交互发生在次级听觉皮层中，从声音开始后30 ms开始，并且在多模态区域中的任何活动之前。在听觉皮层的视听互动，估计在一个线性模型，包括一个总抑制的视觉反应唇读和减少的听觉反应的语音在双峰条件下相比，单峰条件。这些研究结果表明，视听语音整合不尊重经典的层次结构，从感官特定的联想皮层区域，而是从事多个跨模态的机制，在第一阶段的非初级听觉皮层激活。
Hemodynamic studies have shown that the auditory cortex can be activated by visual lip movements and is a site of interactions between auditory and visual speech processing. However, they provide no information about the chronology and mechanisms of these cross-modal processes. We recorded intracranial event-related potentials to auditory, visual, and bimodal speech syllables from depth electrodes implanted in the temporal lobe of 10 epileptic patients (altogether 932 contacts). We found that lip movements activate secondary auditory areas, very shortly (approximate to 10 ms) after the activation of the visual motion area MT/V5. After this putatively feedforward visual activation of the auditory cortex, audiovisual interactions took place in the secondary auditory cortex, from 30 ms after sound onset and before any activity in the polymodal areas. Audiovisual interactions in the auditory cortex, as estimated in a linear model, consisted both of a total suppression of the visual response to lipreading and a decrease of the auditory responses to the speech sound in the bimodal condition compared with unimodal conditions. These findings demonstrate that audiovisual speech integration does not respect the classical hierarchy from sensory-specific to associative cortical areas, but rather engages multiple cross-modal mechanisms at the first stages of nonprimary auditory cortex activation.