[论文解读] Altering sensorimotor simulation impacts early stages of facial expression processing depending on individual differences in alexithymic traits

Arianna Schiano Lomoriello, Antonio Maffei+2 more|arXiv (Cornell University)|Jun 14, 2019

Face Recognition and Perception被引用 4

一句话总结

本研究探讨了感觉运动模拟（特别是面部模仿）如何影响面部表情的早期神经加工，发现个体在解离性特质上的差异会调节这种影响。通过事件相关电位（ERP）研究发现，低解离性个体在模仿干扰下表现出P1振幅的调制，而高解离性个体则表现出N170的调制，表明存在补偿性的视觉加工以及感觉运动-视觉连接的差异。

ABSTRACT

Simulation models of facial expressions suggest that posterior visual areas and brain areas underpinning sensorimotor simulations might interact to improve facial expression processing. According to these models, facial mimicry may contribute to the visual processing of facial expressions by influencing early stages. The aim of the present study was to assess whether/how early sensorimotor simulation influences early stages of face processing. A secondary aim was to investigate the relationship between alexithymic traits and sensorimotor simulation. We monitored P1 and N170 components of the event-related potentials (ERP) in participants performing a fine discrimination task of facial expressions while implementing an animal discrimination task as control condition. In half of the experiment, participants could freely use their facial mimicry whereas in the other half, they had their facial mimicry blocked by a gel. Our results revealed that, on average, both P1 and N170 ERP components were not sensitive to mimicry manipulation. However, when taking into account alexithymic traits, a scenario corroborating sensorimotor simulation models emerged, with two dissociable temporal windows affected by mimicry manipulation as a function of alexithymia levels. Specifically, as a function of mimicry manipulation, individuals with lower alexithymic traits showed modulations of the P1 amplitude, while individuals with higher alexithymic traits showed modulations of the later N170). Furthermore, connectivity analysis at the scalp level suggested increased connectivity between sensorimotor and extrastriate visual regions in individuals with lower alexithymic traits compared to individuals with higher alexithymic traits. Overall, we interpreted these ERPs modulations as compensative visual processing under conditions of interference on the sensorimotor processing.

研究动机与目标

• 检验感觉运动模拟（特别是面部模仿）是否会影响面部表情加工的早期阶段。
• 探究个体在解离性特质上的差异如何影响感觉运动与视觉加工在面部表情感知过程中的相互作用。
• 确定模仿干扰是否以依赖于解离性水平的方式改变ERP成分（P1和N170）。
• 探索感觉运动区域与视觉区域之间的神经连接模式如何随解离性特质而变化。

提出的方法

• 在精细面部表情辨别任务中记录了事件相关电位（ERP）。
• 参与者在两种条件下完成任务：自由面部模仿和通过凝胶阻断模仿。
• 分析P1和N170 ERP成分，以评估早期视觉处理和结构化面部加工阶段。
• 使用标准化自评量表测量解离性特质，将参与者分为高解离性和低解离性组。
• 计算感觉运动区域与侧纹状视觉区域之间的头皮水平功能连接，以检查神经网络的相互作用。
• 设置一个涉及动物辨别的对照条件，以隔离与面部表情加工特异相关的效应。

实验结果

研究问题

• RQ1 通过阻断面部模仿来改变感觉运动模拟，是否会影响面部表情加工过程中早期ERP成分（P1和N170）？
• RQ2 个体在解离性特质上的差异如何调节感觉运动模拟对早期面部加工阶段的影响？
• RQ3 在面部表情感知过程中，基于解离性水平，感觉运动与视觉区域之间的神经连接是否存在差异模式？
• RQ4 当感觉运动模拟被破坏时，高解离性个体是否更依赖视觉加工作为代偿机制？

主要发现

• 解离性特质较低的参与者在面部模仿被阻断时，P1振幅显著调制，表明其早期视觉加工对感觉运动干扰敏感。
• 解离性特质较高的个体在模仿阻断条件下表现出N170成分的显著调制，表明其后期结构化面部加工受到影响。
• 头皮水平连接性分析显示，低解离性个体在感觉运动区域与侧纹状视觉区域之间的功能连接强于高解离性个体。
• 整体ERP模式表明，当感觉运动模拟被破坏时，高解离性个体表现出补偿性的视觉加工。
• 未观察到组平均ERP效应，表明当数据按解离性水平合并时，模仿影响被掩盖。
• 模仿操纵对P1与N170产生可分离的时间窗影响，凸显了面部表情加工中基于特质的神经机制。