Suvilehto Juulia T, Renvall Ville, Nummenmaa Lauri
Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 Aalto, Finland; Aalto NeuroImaging, Aalto University, FI-00076 Aalto, Finland; Center for Social and Affective Neuroscience, Linköping University, SE-58183 Linköping, Sweden.
Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 Aalto, Finland.
Neuroscience. 2021 Jun 1;464:105-116. doi: 10.1016/j.neuroscience.2020.09.015. Epub 2020 Sep 12.
Humans use touch to maintain their social relationships, and the emotional qualities of touch depend on who touches whom. However, it is not known how affective and social dimensions of touch are processed in the brain. We measured haemodynamic brain activity with functional magnetic resonance imaging (fMRI) from 19 subjects (10 males), while they were touched on their upper thigh by either their romantic partner, or an unfamiliar female or male confederate or saw the hand of one of these individuals near their upper thigh but were not touched. We used multi-voxel pattern analysis on pre-defined regions of interest to reveal areas that encode social touch in a relationship-specific manner. The accuracy of the machine learning classifier to identify actor for both feeling touch and seeing hand exceeded the chance level in the primary somatosensory cortex, while in the insular cortex accuracy was above chance level only for the touch condition. When classifying the relationship (partner or stranger), while keeping the toucher sex fixed, amygdala (AMYG), orbitofrontal cortex (OFC), and primary and secondary somatosensory cortices were able to discriminate toucher significantly above chance level. These results suggest that information on the social relationship of the toucher is processed consistently across several regions. More complex information about toucher identity is processed in the primary somatosensory and insular cortices, both of which can be considered early sensory areas.
人类通过触摸来维系社会关系，而触摸的情感特质取决于触摸者与被触摸者的身份。然而，大脑如何处理触摸的情感和社会维度尚不清楚。我们使用功能磁共振成像（fMRI）对19名受试者（10名男性）的大脑血流动力学活动进行了测量，期间他们的大腿上部要么被其恋爱伴侣触摸，要么被陌生女性或男性同盟者触摸，或者看到这些人中的一人的手靠近其大腿上部但未被触摸。我们对预先定义的感兴趣区域进行多体素模式分析，以揭示以特定关系方式编码社会触摸的区域。在初级体感皮层中，用于识别触摸者和看到手的机器学习分类器的准确率超过了随机水平，而在岛叶皮层中，只有触摸条件下的准确率高于随机水平。在对关系（伴侣或陌生人）进行分类时，在保持触摸者性别不变的情况下，杏仁核（AMYG）、眶额皮层（OFC）以及初级和次级体感皮层能够显著高于随机水平地区分触摸者。这些结果表明，触摸者社会关系的信息在多个区域得到一致处理。关于触摸者身份的更复杂信息在初级体感皮层和岛叶皮层中进行处理，这两个区域都可被视为早期感觉区域。
