The neural bases of tactile vitality forms and their modulation by social context

G Rizzolatti,A D'Alessio,G Di Cesare,M Marchi

doi:10.1038/s41598-021-87919-z

Abstract

People communicate using speech, gestures, and, less frequently, touches. An example of tactile communication is represented by handshake. Customs surrounding handshake vary in different cultures. In Western societies is mostly used when meeting, parting, as a sign of congratulations or at the end of a successful business. Despite its importance in social life, the neural mechanism underlying the affective components conveyed by handshake (“tactile vitality forms”) is unknown. Here we combined functional magnetic resonance imaging (fMRI) and electromyography (EMG), to investigate the neural affective activations during handshakes. We demonstrated that handshake conveying gentle or aggressive tactile vitality forms produces a stronger activation of the dorso-central insula. The simultaneous presence of emotional facial expressions modulates the activation of this insular sector. Finally, we provide evidence that the cingulate cortex is involved in the processing of facial expressions conveying different vitality forms.

Highlights

People communicate using speech, gestures, and, less frequently, touches
The results showed that handshake conveying tactile vitality forms produced, relative to control, a strong activation of the dorso-central insula and of the middle cingulate cortex
A similar, but weaker, cortical activation pattern was found during the control condition vs. baseline

Summary

Introduction

Gestures, and, less frequently, touches. An example of tactile communication is represented by handshake. We demonstrated that handshake conveying gentle or aggressive tactile vitality forms produces a stronger activation of the dorso-central insula. Vitality forms represent the way (“the form”) with which an action is performed, regardless of whether the action is devoid of emotional content, so called “cold actions” like reaching, grasping, taking, giving, or it is emotionally laden. An example of the latter action type could be anger. Considering that the definition of vitality form by Stern concerned the visual aspects of actions, we will use here the term tactile vitality forms to describe the affective and communicative aspects of the handshake

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Conclusion