Empathy for pain and touch in the human somatosensory cortex

Although feeling pain and touch has long been considered inherently private, recent neuroimaging and neurophysiological studies hint at the social implications of this experience. Here we used somatosensory-evoked potentials (SEPs) to investigate whether mere observation of painful and tactile stimuli delivered to a model would modulate neural activity in the somatic system of an onlooker. Viewing video clips showing pain and tactile stimuli delivered to others, respectively, increased and decreased the amplitude of the P45 SEP component that reflects the activity of the primary somatosensory cortex (S1). These modulations correlated with the intensity but not with the unpleasantness of the pain and touch ascribed to the model or the aversion induced in the onlooker by the video clips. Thus, modulation of S1 activity contingent upon observation of others' pain and touch may reflect the mapping of sensory qualities of observed painful and tactile stimuli. Results indicate that the S1 is not only involved in the actual perception of pain and touch but also plays an important role in extracting somatic features from social interactions.