Szycik Gregor Rafael, Tausche Peggy, Münte Thomas F
Department of Neuropsychology, Otto von Guericke University, University of Magdeburg, Universitätsplatz 2, Gebäude 24, 39106 Magdeburg, Germany.
Brain Res. 2008 Jul 18;1220:142-9. doi: 10.1016/j.brainres.2007.08.027. Epub 2007 Aug 19.
Speech comprehension in noisy environments is greatly improved by the availability of visual information, i.e. lip and facial movements. This suggests that the brain is in possession of an audiovisual integration mechanism supplementing speech comprehension. To reveal the respective brain areas, we used a step-wise functional neuroimaging approach in healthy German speaking subjects. First, a functional localizer session using a block design with auditory speech, visual speech (lip movements, no audio), and audiovisual speech (audio and video-signal in sync) was used to identify areas activated by auditory and visual speech, which showed in addition further increased activity in the audiovisual condition. This procedure revealed two clusters of brain activity in the posterior part of the superior temporal sulcus bilaterally. In a second session using slow-event-related imaging in conjunction with sparse sampling, these functionally defined volumes were further examined in a design crossing audiovisual congruity and intelligibility (with/without added noise). Within these areas, regions showing an interaction of audiovisual congruity and intelligibility were found with the greatest activity for incongruent speech stimuli with added noise. This underscores their role in audiovisual integration. We propose that the stepwise approach introduced here allows a finer analysis of audiovisual speech integration than previous methods.
在嘈杂环境中，视觉信息（即嘴唇和面部动作）的可用性能极大地提高言语理解能力。这表明大脑拥有一种补充言语理解的视听整合机制。为了揭示相应的脑区，我们在健康的德语使用者中采用了逐步功能神经成像方法。首先，使用一个包含听觉言语、视觉言语（嘴唇动作，无声音）和视听言语（音频和视频信号同步）的块设计进行功能定位实验，以识别由听觉和视觉言语激活的区域，这些区域在视听条件下还表现出进一步增强的活动。这一过程在双侧颞上沟后部揭示了两组脑活动。在第二个实验中，结合稀疏采样使用慢事件相关成像，在一个交叉视听一致性和可懂度（有/无附加噪声）的设计中对这些功能定义的区域进行了进一步检查。在这些区域内，发现了显示视听一致性和可懂度相互作用的区域，对于添加噪声的不一致言语刺激，其活动最为强烈。这突出了它们在视听整合中的作用。我们提出，这里介绍的逐步方法比以前的方法能对视听言语整合进行更精细的分析。
