The multiform motor cortical output: Kinematic, predictive and response coding.
Observing actions performed by others entails a subliminal activation of primary motor cortex reflecting the components encoded in the observed action. One of the most debated issues concerns the role of this output: Is it a mere replica of the incoming flow of information (kinematic coding), is it oriented to anticipate the forthcoming events (predictive coding) or is it aimed at responding in a suitable fashion to the actions of others (response coding)? The aim of the present study was to disentangle the relative contribution of these three levels and unify them into an integrated view of cortical motor coding. We combined transcranial magnetic stimulation (TMS) and electromyography recordings at different timings to probe the excitability of corticospinal projections to upper and lower limb muscles of participants observing a soccer player performing: (i) a penalty kick straight in their direction and then coming to a full stop, (ii) a penalty kick straight in their direction and then continuing to run, (iii) a penalty kick to the side and then continuing to run. The results show a modulation of the observer's corticospinal excitability in different effectors at different times reflecting a multiplicity of motor coding. The internal replica of the observed action, the predictive activation, and the adaptive integration of congruent and non-congruent responses to the actions of others can coexist in a not mutually exclusive way. Such a view offers reconciliation among different (and apparently divergent) frameworks in action observation literature, and will promote a more complete and integrated understanding of recent findings on motor simulation, motor resonance and automatic imitation.
['Sartori|Luisa|L|', 'Betti|Sonia|S|', 'Chinellato|Eris|E|', 'Castiello|Umberto|U|']
D000328:Adult D001696:Biomechanical Phenomena D004576:Electromyography D019054:Evoked Potentials, Motor D005260:Female D006801:Humans D007100:Imitative Behavior D008297:Male D009039:Motion Perception D009044:Motor Cortex D018482:Muscle, Skeletal D010775:Photic Stimulation D050781:Transcranial Magnetic Stimulation D055815:Young Adult
Transcranial magnetic stimulation Action observation Motor resonance Motor evoked potentials