Kick with the finger: symbolic actions shape motor cortex excitability.
A large body of research indicates that observing actions made by others is associated with corresponding motor facilitation of the observer's corticospinal system. However, it is still controversial whether this matching mechanism strictly reflects the kinematics of the observed action or its meaning. To test this issue, motor evoked potentials induced by single-pulse transcranial magnetic stimulation were recorded from hand and leg muscles while participants observed a symbolic action carried out with the index finger, but classically performed with the leg (i.e., a soccer penalty kick). A control condition in which participants observed a similar (but not symbolic) hand movement was also included. Results showed that motor facilitation occurs both in the observer's hand (first dorsal interosseous) and leg (quadriceps femoris) muscles. The present study provides evidence that both the kinematics and the symbolic value of an observed action are able to modulate motor cortex excitability. The human motor system is thus not only involved in mirroring observed actions but is also finely tuned to their symbolic value.
Dipartimento di Psicologia Generale, Università di Padova, Via Venezia 8, 35131, Padova, Italy.
Sonia
S
Betti
Dipartimento di Psicologia Generale, Università di Padova, Via Venezia 8, 35131, Padova, Italy.|Center for Cognitive Neuroscience, Università di Padova, Padova, Italy.|Centro Linceo Interdisciplinare Beniamino Segre, Accademia dei Lincei, Roma, Italy.
Umberto
U
Castiello
Dipartimento di Psicologia Generale, Università di Padova, Via Venezia 8, 35131, Padova, Italy.|Center for Cognitive Neuroscience, Università di Padova, Padova, Italy.
Luisa
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Sartori
D000328:Adult; D001696:Biomechanical Phenomena; D019054:Evoked Potentials, Motor; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000294:innervation / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D052097:Quadriceps Muscle / Q000294:innervation / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
action observation; motor evoked potentials; motor resonance; transcranial magnetic stimulation