Department of Psychology, Catholic University of Milan, Milan, Italy.
Research Unit in Affective and Social Neuroscience, Catholic University of Milan, Milan, Italy.
Brain Behav. 2020 Jul;10(7):e01663. doi: 10.1002/brb3.1663. Epub 2020 May 29.
Gestures characterize individuals' nonverbal communicative exchanges, taking on different functions. Several types of research in the neuroscientific field have been interested in the investigation of the neural correlates underlying the observation and implementation of different gestures categories. In particular, different studies have focused on the neural correlates underlying gestures observation, emphasizing the presence of mirroring mechanisms in specific brain areas, which appear to be involved in gesture observation and planning mechanisms.
Specifically, the present study aimed to investigate the neural mechanisms, through the use of functional Near-Infrared Spectroscopy (fNIRS), underlying the observation of affective, social, and informative gestures with positive and negative valence in individuals' dyads composed by encoder and decoder. The variations of oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations of both individuals were collected simultaneously through the use of hyperscanning paradigm, allowing the recording of brain responsiveness and interbrain connectivity.
The results showed a different brain activation and an increase of interbrain connectivity according to the type of gestures observed, with a significant increase of O2Hb brain responsiveness and interbrain connectivity and a decrease of HHb brain responsiveness for affective gestures in the dorsolateral prefrontal cortex (DLPFC) and for social gestures in the superior frontal gyrus (SFG). Furthermore, concerning the valence of the observed gestures, an increase of O2Hb brain activity and interbrain connectivity was observed in the left DLPFC for positive affective gestures compared to negative ones.
In conclusion, the present study showed different brain responses underlying the observation of different types of positive and negative gestures. Moreover, interbrain connectivity calculation allowed us to underline the presence of mirroring mechanisms involved in gesture-specific frontal regions during gestures observation and action planning.
手势是个体非言语交际交流的特征，具有不同的功能。神经科学领域的几项研究都对观察和实施不同手势类别的神经相关因素感兴趣。特别是，一些研究集中在手势观察的神经相关因素上，强调了特定大脑区域镜像机制的存在，这些机制似乎与手势观察和计划机制有关。
具体来说，本研究旨在通过使用功能近红外光谱（fNIRS）研究个体在由编码器和解码器组成的二人组中观察具有积极和消极情感的情感、社交和信息手势的神经机制。通过使用超扫描范式同时收集两个个体的含氧（O2Hb）和去氧（HHb）血红蛋白浓度的变化，允许记录大脑反应和脑间连接。
结果表明，根据观察到的手势类型，大脑激活和脑间连接会有所不同，在背外侧前额叶皮层（DLPFC）中，情感手势的 O2Hb 大脑反应和脑间连接显著增加，HHb 大脑反应减少；在额上回（SFG）中，社交手势的 O2Hb 大脑反应和脑间连接显著增加。此外，对于观察到的手势的效价，与消极情感手势相比，积极情感手势在左 DLPFC 中观察到 O2Hb 大脑活动和脑间连接增加。
总之，本研究表明，不同类型的积极和消极手势的观察存在不同的大脑反应。此外，脑间连接的计算使我们能够强调在手势观察和动作规划期间涉及手势特定额叶区域的镜像机制的存在。
