Temporal dynamic of neural mechanisms involved in empathy for pain: an event-related brain potential study

Previous neuroimaging studies have identified a neural circuit that is involved in empathy for pain. However, the temporal dynamics of neural activities underlying empathic processes remains poorly understood. This was investigated in the current study by recording event-related brain potentials (ERPs) from healthy adults who were presented with pictures or cartoons of hands that were in painful or neutral situations. Subjects performed a pain judgment task that required attention to pain cues in the stimuli or a counting task that withdrew their attention from these cues. The ERP results showed early differentiation between painful and neutral stimuli over the frontal lobe at 140 ms after sensory stimulation. A long-latency empathic response was observed after 380 ms over the central-parietal regions and was more salient over the left than right hemispheres. The early and late empathic responses were, respectively, modulated by contextual reality of stimuli and by top-down attention to the pain cues. Moreover, the mean ERP amplitudes at 140-180 ms were correlated with subjective reports of the degree of perceived pain of others and of self-unpleasantness. The ERP results support a model of empathy for pain consisting of early emotional sharing and late cognitive evaluation.