Seeing touch and pain in a stranger modulates the cortical responses elicited by somatosensory but not auditory stimulation

Authors

  • Elia Valentini,

    1. Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
    2. Fondazione Santa Lucia, IRCCS and Department of Psychology, “La Sapienza” University of Rome, Rome, Italy
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  • Meng Liang,

    1. Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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  • Salvatore Maria Aglioti,

    1. Fondazione Santa Lucia, IRCCS and Department of Psychology, “La Sapienza” University of Rome, Rome, Italy
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  • Gian Domenico Iannetti

    Corresponding author
    1. Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
    • Department of Neuroscience, Physiology and Pharmacology, Medical Sciences Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Abstract

Viewing other's pain inhibits the excitability of the motor cortex and also modulates the neural activity elicited by a concomitantly delivered nociceptive somatosensory stimulus. As the neural activity elicited by a transient nociceptive stimulus largely reflects non nociceptive-specific, multimodal neural processes, here we tested, for the first time, whether the observation of other's pain preferentially affects the brain responses elicited by nociceptive stimulation, or instead similarly modulates those elicited by stimuli belonging to a different sensory modality. Using 58-channel electroencephalography (EEG), we recorded the cortical responses elicited by laser and auditory stimulation during the observation of videoclips showing either noxious or non-noxious stimulation of a stranger's hand. We found that the observation of other's pain modulated the cortical activity consisting in an event-related desynchronization in the β band (β ERD), and elicited by nociceptive laser stimuli, but not by auditory stimuli. Using three different source analysis approaches, we provide converging evidence that such modulation affected neural activity in the contralateral primary sensorimotor cortex. The magnitude of this modulation correlated well with a subjective measure of similarity between the model's hand and the onlooker's representation of the hand. Altogether, these findings demonstrate that the observation of other's pain modulates, in a somatosensory-specific fashion, the cortical responses elicited by nociceptive stimuli in the sensorimotor cortex contralateral to the stimulated hand. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.

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