a Department of Psychology and NeuroMI, Milan Center for Neuroscience , University of Milano-Bicocca , Milan , Italy.
b Laboratory of Neuropsychology , IRCCS Istituto Auxologico Italiano , Milan , Italy.
Soc Neurosci. 2017 Oct;12(5):560-569. doi: 10.1080/17470919.2016.1197853. Epub 2016 Jun 23.
Coding the direction of others' gestures is a fundamental human ability, since it allows the observer to attend and react to sources of potential interest in the environment. Shifts of attention triggered by action observation have been reported to occur early in infancy. Yet, the neurophysiological underpinnings of such action priming and the properties of gestures that might be crucial for it remain unknown. Here, we addressed these issues by recording electroencephalographic activity (EEG) from 6-month-old infants cued with spatially non-predictive hand grasping toward or away from the position of a target object, i.e., valid and invalid trials, respectively. Half of the infants were cued with a gesture executable by a human hand (possible gesture) and the other half with a gesture impossible to be executed by a human hand. Results show that the amplitude enhancement of the posterior N290 component in response to targets in valid trials, as compared to invalid trials, was present only for infants seeing possible gestures, while it was absent for infants seeing impossible gestures. These findings suggest that infants detect the biomechanical properties of human movements when processing hand gestures, relying on this information to orient their visual attention toward the target object.
对他人手势方向进行编码是人类的一项基本能力，因为它可以使观察者关注并对环境中潜在感兴趣的来源做出反应。据报道，动作观察会引发注意力转移，这种转移在婴儿期早期就已经发生。然而，这种动作启动的神经生理基础以及对于这种启动可能至关重要的手势特征尚不清楚。在这里，我们通过记录 6 个月大婴儿的脑电图（EEG）来解决这些问题，这些婴儿在被提示用手向目标物体的位置或远离该位置进行抓握时（即有效和无效试验）会受到空间非预测性的刺激。一半的婴儿被提示用人类手可以执行的手势（可能的手势），另一半婴儿被提示用人类手无法执行的手势。结果表明，与无效试验相比，在有效试验中，对目标的反应增强了后 N290 成分的振幅，这种情况仅出现在看到可能的手势的婴儿中，而在看到不可能的手势的婴儿中则不存在。这些发现表明，婴儿在处理手手势时会检测到人类运动的生物力学特性，并依赖这些信息将视觉注意力转向目标物体。
