title: Somatosensory mu activity reflects imagined pain intensity of others.
abstract: In accordance with simulation theories of empathy, the somatosensory cortex is involved in the perception of pain of others. Cognitive processes, like perspective taking, can alter empathy-related activity within the somatosensory cortex. The current study investigates whether this modulation is caused by the imagined sensation of pain or by the cognitive load of a perspective-taking task. Applying a within-subject design, participants (N = 30) watched pictures of painful and nonpainful actions, while imagining reduced, normal, or increased pain perception of the observed individual. Mu activity (8-13 Hz), which is inversely correlated with sensorimotor-cortex activity, was measured via EEG. To calculate mu activity (central electrodes) and alpha activity (occipital electrodes), which served as a control for effects of cognitive load, a fast Fourier transform was applied. Mu suppression linearly increased from reduced to normal to increased imagined pain (p < .05), while alpha activity was unaffected by the imagined pain (p > .80). Suppression of the 8-13 Hz band at central and occipital electrodes was stronger in response to painful actions compared to nonpainful actions (p < .01). These results indicate that modulation of mu activity through perspective taking reflects the imagined pain intensity and not the cognitive load induced by the task.
authors.affiliation: Institute of Experimental Psychology, University of Düsseldorf, Düsseldorf, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hoenen
authors.affiliation: Institute of Experimental Psychology, University of Düsseldorf, Düsseldorf, Germany.
authors.forename: Katrin T
authors.initials: KT
authors.lastname: Lübke
authors.affiliation: Institute of Experimental Psychology, University of Düsseldorf, Düsseldorf, Germany.
authors.forename: Bettina M
authors.initials: BM
authors.lastname: Pause
mesh_terms: D000328:Adult; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography; D004645:Empathy / Q000502:physiology*; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D010146:Pain / Q000523:psychology*; D058748:Pain Perception / Q000502:physiology*; D010775:Photic Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Empathy; Mirror neuron system; Mu activity; Pain perception; Perspective taking