The Different Effects of Firsthand Pain and Nonpain Electrical Stimulation on Pain Empathy: An EEG Study.

Background: Empathy for pain is a complex psychological process that enables us to understand the feelings of others experiencing pain. Personal pain experiences may shape our empathetic responses, though the precise relationship between empathy for pain and pain perception is not fully understood. Objective: This study investigates how firsthand pain experiences influence brain responses related to empathy for pain. Methods: We recruited 26 participants who underwent either painful or nonpainful electrical stimulation. They were then shown static pictures of hands in painful and nonpainful situations and asked to report their subjective ratings of pain empathy. Electroencephalograph activity was recorded to analyze the neural basis of their experiences. Results: Participants who experienced painful stimulation reported higher empathy levels when viewing painful images. Electroencephalograph data revealed that painful stimulation elicited larger N1 and P2 amplitudes at the Cz electrode compared to nonpainful stimulation. It also enhanced N2 amplitudes in the frontal-central region when viewing painful pictures. Nonpainful stimulation reduced the discriminatory ability of N2 for subsequent painful and nonpainful images. Correlation analysis showed that individuals with higher pain sensitivity had greater variation in P2 responses to painful and nonpainful stimuli but less variation in N2 responses related to pain empathy. Conclusions: These findings suggest that experiencing pain directly may enhance brain responses to others' pain, thereby increasing levels of pain empathy. This enhancement may be influenced by individual pain sensitivity and is less pronounced in those with high pain sensitivity.