Dissociable Processing of Emotional and Neutral Body Movements Revealed by μ-Alpha and Beta Rhythms

Abstract

Both when actions are executed and observed, electroencephalography (EEG) has shown reduced alpha-band (8–12 Hz) oscillations over sensorimotor cortex. This ‘μ-alpha’ suppression is thought to reflect mental simulation of action, which has been argued to support internal representation of others’ emotional states. Despite the proposed role of simulation in emotion perception, little is known about the effect of emotional content on μ-suppression. We recorded high-density EEG while participants viewed point-light displays of emotional vs neutral body movements in ‘coherent’ biologically plausible and ‘scrambled’ configurations. Although coherent relative to scrambled stimuli elicited μ-alpha suppression, the comparison of emotional and neutral movement, controlling for basic visual input, revealed suppression effects in both alpha and beta bands. Whereas alpha-band activity reflected reduced power for emotional stimuli in central and occipital sensors, beta power at frontocentral sites was driven by enhancement for neutral relative to emotional actions. A median-split by autism-spectrum quotient score revealed weaker μ-alpha suppression and beta enhancement in participants with autistic tendencies, suggesting that sensorimotor simulation may be differentially engaged depending on social capabilities. Consistent with theories of embodied emotion, these data support a link between simulation and social perception while more firmly connecting emotional processing to the activity of sensorimotor systems.