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

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.