Motor preparation during pain observation does not influence event-related Mu and Beta desynchronization

Previous EEG research has shown that observing others in pain increases sensorimotor activity, as indexed by Mu (7-12 Hz) and Beta (13-30 Hz) desynchronization. Such activity is often interpreted as reflecting empathic processing through shared neural representations between the observer and target. In everyday life, observing another in pain can trigger a range of potential action tendencies (e.g., withdrawing, helping, or protecting oneself), but EEG studies typically restrict movement to avoid artifacts. This immobility may produce an artificial scenario that limits our understanding of how motor readiness and empathic processing interact. The present study examined whether engaging the motor system (via a simple key press) modulates these neural responses. Participants observed videos and pictures of a hand being stabbed by a needle or touched by a Q-tip. In half of the blocks, they prepared and executed a speeded key press to a Go signal; in the other half, they remained still. Results revealed Mu and Beta desynchronization during pain observation regardless of movement condition, replicating prior findings. These effects were unrelated to reaction times or empathy traits, suggesting that sensorimotor resonance during pain observation reflects a stable response rather than one contingent on task-specific motor preparation.