Electrocorticography Reveals Enhanced Visual Cortex Responses to Visual Speech.
Electrocorticography Reveals Enhanced Visual Cortex Responses to Visual Speech.
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DOI：
10.1093/cercor/bhu127
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发表时间：
2015-11
期刊：
影响因子：
3.7
通讯作者：
Inga M. Schepers;D. Yoshor;M. Beauchamp
中科院分区：
文献类型：
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作者：
Inga M. Schepers;D. Yoshor;M. Beauchamp
人类的语音包含听觉和视觉成分，由各自的感觉皮层处理。我们测试了一个简单的模型，其中任务相关的语音信息在皮层处理过程中得到增强。当听觉成分不提供信息时，视觉语音是最重要的。因此，该模型预测，与视听（AV）语音相比，视觉皮层对仅视觉（V）语音的反应应该增强。我们记录了神经元活动的患者认为只有语音（A），V和AV语音。视觉皮层表现出强烈的增加，高伽玛波段功率和强烈的下降，在阿尔法波段功率V和AV语音。与模型预测一致，V语音的伽马波段增加和阿尔法波段减少更强。该模型预测，听觉成分的无信息性（不仅仅是它的缺失）是关键因素，我们在第二个实验中测试了这一预测，在这个实验中，视觉语音与听觉白色噪声配对。正如预测的那样，视觉语音与听觉噪声显示增强的视觉皮层反应相对于AV语音。对影响的解剖学位点的检查表明，所有视觉区域，包括初级视觉皮层，都表现出增强的反应。当视觉信息对理解最重要时，视觉皮层对语音的反应会增强。
Human speech contains both auditory and visual components, processed by their respective sensory cortices. We test a simple model in which task-relevant speech information is enhanced during cortical processing. Visual speech is most important when the auditory component is uninformative. Therefore, the model predicts that visual cortex responses should be enhanced to visual-only (V) speech compared with audiovisual (AV) speech. We recorded neuronal activity as patients perceived auditory-only (A), V, and AV speech. Visual cortex showed strong increases in high-gamma band power and strong decreases in alpha-band power to V and AV speech. Consistent with the model prediction, gamma-band increases and alpha-band decreases were stronger for V speech. The model predicts that the uninformative nature of the auditory component (not simply its absence) is the critical factor, a prediction we tested in a second experiment in which visual speech was paired with auditory white noise. As predicted, visual speech with auditory noise showed enhanced visual cortex responses relative to AV speech. An examination of the anatomical locus of the effects showed that all visual areas, including primary visual cortex, showed enhanced responses. Visual cortex responses to speech are enhanced under circumstances when visual information is most important for comprehension.