What makes touch social: probing the brain mechanisms supporting affective touch with functional MRI in humans at 3 Tesla

Motivation: Touch is the first sensory modality to develop. C-tactile (CT) nerves in hairy skin are involved in slow/gentle touch, and social interactions. However, brain mechanisms processing the affective aspects of touch remain under-studied. Goal(s): We characterised the network of brain regions supporting perception of affective touch. Approach: 11-volunteers underwent fMRI at clinically relevant 3T field strengths while their arm was gently brushed and compared with brushing to remove a marker. Results: We found a network of brain regions involved in affective touch processing including the posterior superior temporal sulcus (pSTS), inferior frontal gyrus (IFG), temporoparietal junction (TPJ). Impact: This study characterises the brain network processing affective touch, critical given the central role of touch during development and its social function throughout the lifespan. It helps understanding brain responses in adults born pre-term, where experience of touch was interrupted/reduced.