Primary somatosensory cortical processing in tactile communication

Touch is an essential form of non-verbal communication. While language and its neural basis are widely studied, tactile communication is less well understood. We used fMRI and multivariate pattern analyses in pairs of emotionally close adults to examine the neural basis of human-to-human tactile communication. In each pair, a participant was designated either as sender or as receiver. The sender was instructed to communicate specific messages by touching only the arm of the receiver, who was inside the scanner. The receiver then identified the message based on the touch gesture alone. We designed two multivariate decoders – one based on the sender's intent (sender-decoder), and another based on the receiver's response (receiver-decoder). Both were able to differentiate accurately the messages using signals from the receiver's primary somatosensory cortex (S1). The receiver-decoder, which is based on receivers' interpretations of the touch gestures, outperformed the sender-decoder, which is more indicative of sensory input. Our results support the notion of non-sensory factors being represented in S1. Content: anonymized T1, functional EPI from run1 and run 2 per subject, analysis script (ECOC_s1.mat) Log files can be found here: https://zenodo.org/uploads/10012490