Biological Psychology and Neuropsychology, University of Hamburg, Von-Melle-Park 11, D-20146 Hamburg, Germany.
Neuropsychologia. 2010 Jun;48(7):2158-66. doi: 10.1016/j.neuropsychologia.2010.04.007. Epub 2010 Apr 10.
The present study investigated the neural basis of lip-reading in patients treated for congenital bilateral cataracts using functional magnetic resonance imaging (fMRI). These patients represent a model to study the role of visual experience in early infancy for the development of visual functions. Short video clips with an adult speaker's lips mouthing different words were presented. The participants were asked to indicate whether the current word was the same as the previous one (one-back matching task). A control condition consisted of the same stimuli but with the task to judge whether the position of a small black dot superimposed on the lips changed location between trials. During both tasks, neural activity as indexed by fMRI, and behavioral data were recorded. The cataract patients' lip-reading performance was worse than that of a group of normally sighted controls, matched for age, gender, and education. By contrast, these groups did not differ in the visual control task. Only the control group showed reliable lip-reading specific activations in superior and middle temporal areas and in right parietal cortex, resulting in a significant group effect for these brain areas. Additional control participants with a late onset of visual impairments matching those of the cataract group showed comparable behavioral performance and similar fMRI activations in superior temporal areas as the normally sighted controls. These results suggest that a sensitive phase in early infancy might exist during which visual acuity must be sufficiently high to discriminate lip movements in order to allow for the emergence of a regular neural lip-reading system.
本研究使用功能磁共振成像（fMRI）调查了接受先天性双侧白内障治疗的患者的唇读神经基础。这些患者代表了一个研究模型，用于研究婴儿早期视觉经验对视觉功能发展的作用。参与者观看了带有成年演讲者嘴唇说出不同单词的短视频片段，并被要求指出当前单词是否与前一个单词相同（一次匹配任务）。控制条件包括相同的刺激，但任务是判断叠加在嘴唇上的小黑点的位置在试验之间是否发生了变化。在这两个任务中，记录了 fMRI 索引的神经活动和行为数据。白内障患者的唇读表现不如一组年龄、性别和教育程度相匹配的正常视力对照组。相比之下，这些组在视觉控制任务中没有差异。只有对照组在颞上区和右侧顶叶皮层中显示出可靠的唇读特异性激活，这些脑区的组间差异显著。具有与白内障组相似的视觉障碍发病时间的额外对照组参与者表现出类似的行为表现和与正常视力对照组相似的颞上区 fMRI 激活。这些结果表明，在婴儿早期可能存在一个敏感阶段，在此期间，视力必须足够高，以区分嘴唇运动，以便形成一个正常的神经唇读系统。
