title: Dynamic modulation of human motor activity when observing actions.
abstract: Previous studies have demonstrated that when we observe somebody else executing an action many areas of our own motor systems are active. It has been argued that these motor activations are evidence that we motorically simulate observed actions; this motoric simulation may support various functions such as imitation and action understanding. However, whether motoric simulation is indeed the function of motor activations during action observation is controversial, due to inconsistency in findings. Previous studies have demonstrated dynamic modulations in motor activity when we execute actions. Therefore, if we do motorically simulate observed actions, our motor systems should also be modulated dynamically, and in a corresponding fashion, during action observation. Using magnetoencephalography, we recorded the cortical activity of human participants while they observed actions performed by another person. Here, we show that activity in the human motor system is indeed modulated dynamically during action observation. The finding that activity in the motor system is modulated dynamically when observing actions can explain why studies of action observation using functional magnetic resonance imaging have reported conflicting results, and is consistent with the hypothesis that we motorically simulate observed actions.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom. c.m.press@reading.ac.uk
authors.forename: Clare
authors.initials: C
authors.lastname: Press
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cook
authors.forename: Sarah-Jayne
authors.initials: SJ
authors.lastname: Blakemore
authors.forename: James
authors.initials: J
authors.lastname: Kilner
mesh_terms: D000293:Adolescent; D000328:Adult; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007100:Imitative Behavior / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000033:anatomy & histology / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult