Moebius syndrome (MBS) is characterized by the congenital absence or underdevelopment of cranial nerves VII and VI, leading to facial palsy and impaired lateral eye movements. As a result, MBS individuals cannot produce facial expressions and did not develop motor programs for facial expressions. In the latest model of sensorimotor simulation, an iterative communication between somatosensory, motor/premotor cortices, and visual regions has been proposed, which should allow more efficient discriminations among subtle facial expressions. Accordingly, individuals with congenital facial motor disability, specifically with MBS, should exhibit atypical communication within this network. Here, we aimed to test this facet of the sensorimotor simulation models. We estimated the functional connectivity between the visual cortices for face processing and the sensorimotor cortices in healthy and MBS individuals. To this aim, we studied the strength of beta band functional connectivity between these two systems using high-density EEG, combined with a change detection task with facial expressions (and a control condition involving non-face stimuli). The results supported our hypothesis such that when discriminating subtle facial expressions, participants affected by congenital facial palsy (compared to healthy controls) showed reduced connectivity strength between sensorimotor regions and visual regions for face processing. This effect was absent for the condition with non-face stimuli. These findings support sensorimotor simulation models and the communication between sensorimotor and visual areas during subtle facial expression processing.

中文翻译：

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测试先天性面瘫患者感觉运动和面部处理视觉区域之间的脑电图功能连接

Moebius 综合征 (MBS) 的特征是颅神经 VII 和 VI 先天性缺失或发育不全，导致面部麻痹和侧眼球运动受损。因此，MBS 个体无法产生面部表情，也没有开发面部表情的运动程序。在最新的感觉运动模拟模型中，已经提出了体感、运动/前运动皮层和视觉区域之间的迭代通信，这应该可以更有效地区分细微的面部表情。因此，患有先天性面部运动障碍的个体，特别是患有 MBS 的个体，应该在该网络中表现出非典型的交流。在这里，我们旨在测试感觉运动模拟模型的这一方面。我们估计了健康人和 MBS 个体的面部处理视觉皮层与感觉运动皮层之间的功能连接。为此，我们使用高密度脑电图研究了这两个系统之间 β 波段功能连接的强度，并结合面部表情变化检测任务（以及涉及非面部刺激的控制条件）。结果支持我们的假设，即在区分细微的面部表情时，受先天性面瘫影响的参与者（与健康对照组相比）表现出面部处理的感觉运动区域和视觉区域之间的连接强度降低。对于非面部刺激的情况，这种效果不存在。