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Neuroscience studies on the social sharing of observed or imagined pain focused on whether empathic pain resonance is linked to affective or sensory nodes of the pain matrix. However, empathy, like other complex cognitive processes, is inherently linked to the activation of functional networks rather than of separate brain areas. Here, we used magnetoencephalography (MEG) to explore the relationship between empathy and functional coupling of neuronal activity in primary somatosensory (SI) and motor (MI) cortices. MEG recording was performed while healthy participants observed movie-clips depicting the static hand of a stranger model, the same hand deeply penetrated by a needle, or gently touched by a Q-tip. Subjects were asked to rate the movie-derived sensations attributed to self or to the model. For each type of clip observation, we analyzed spectral power and coherence values in alpha, beta, and gamma frequency bands. While spectral power indexes separate neural activity in SI and MI, coherence values index functional cross-talk between these two areas. No power changes of SI or MI sources were induced by observation conditions in any of the frequency bands. Crucially, gamma-band coherence values were significantly higher during needle-in-hand than touch and static hand observation and correlated with self-and other-referred pain ratings derived from needle-in-hand movies observation. Thus, observation of others' pain increases neuronal synchronization and cross-talk between the onlookers' sensory and motor cortices, indicating that empathic resonance relies upon the activity of functional networks more than of single areas.

Given previous reports of strong interactions between vision and somatic senses, we investigated whether vision of the body modulates pain perception. Participants looked into a mirror aligned with their body midline at either the reflection of their own left hand (creating the illusion that they were looking directly at their own right hand) or the reflection of a neutral object. We induced pain using an infrared laser and recorded nociceptive laser-evoked potentials (LEPs). We also collected subjective ratings of pain intensity and unpleasantness. Vision of the body produced clear analgesic effects on both subjective ratings of pain and the N2/P2 complex of LEPs. Similar results were found during direct vision of the hand, without the mirror. Furthermore, these effects were specific to vision of one's own hand and were absent when viewing another person's hand. These results demonstrate a novel analgesic effect of non-informative vision of the body.

Seeing actions, emotions and feelings of other individuals may activate resonant mechanisms that allow the empathic understanding of others' states. Being crucial for implementing pro-social behaviors, empathy is considered as inherently altruistic. Here we explored whether the personal experience of pain make individuals less inclined to share others' pain. We used laser-evoked potentials (LEPs) to explore whether observation of painful or non-noxious stimuli delivered to a stranger model induced any modulation in the pain system of onlookers who were suffering from pain induced by the laser stimuli. After LEPs recording, participants rated intensity and unpleasantness of the laser pain, and of the pain induced by the movie in themselves and in the model. Mere observation of needles penetrating the model's hand brought about a specific reduction of the N1/P1 LEP component, related to the activation of somatic nodes of the pain matrix. Such reduction is stronger in onlookers who rated the pain intensity induced by the pain movie as higher in themselves and lower in the model. Conversely, the N2a-P2 component, supposedly associated to affective pain qualities, did not show any specific modulation during observation of others' pain. Thus, viewing 'flesh and bone' pain in others specifically modulates neural activity in the pain matrix sensory node. Moreover, this socially-derived inhibitory effect is correlated with the intensity of the pain attributed to self rather than to others suggesting that being in pain may bias the empathic relation with stranger models towards self-centred instead than other-related stances.

Objective: To investigate the possible presence of multiple spino-thalamic pathways with different conduction velocities (CVs) in the human spinal cord., Methods: Laser evoked potentials (LEPs) were recorded in 10 healthy subjects after stimulation of the dorsal midline at four vertebral level: C5, T2, T6, and T10. This method allowed us to minimize the influence of the conduction in the peripheral fibers and to calculate the spinal CV in two different ways: (1) the reciprocal of the slope of the regression line was obtained from the latencies of the different LEP components, and (2) the distance between C5 and T10 was divided by the latency difference of the responses at the two sites. In particular, we considered the middle-latency N1 potential (latencies of around 135, 150, 157, and 171 ms after stimulation at C5, T2, T6, and T10 levels, respectively), which is generated in the second somatosensory (SII) area, and the late P2 response (latencies of around 336, 344, 346, and 362 ms after stimulation at C5, T2, T6, and T10 levels, respectively), which is generated in the anterior cingulate cortex (ACC)., Results: The calculated CV of the spinal fibers generating the N1 potential (around 9 m/s) was significantly different (P<0.05) from the one of the pathway producing the P2 response (around 13 m/s)., Conclusions: Our results suggest that the N1 and the P2 LEP components are generated by two parallel spinal pathways., Significance: Both the N1 and P2 potentials should be recorded in the clinical routine since a dissociated abnormality of either response may be found in lesions of the nociceptive system not only in the brain, but also at spinal cord level.