title: Locomotor adaptation is modulated by observing the actions of others.
abstract: Observing the motor actions of another person could facilitate compensatory motor behavior in the passive observer. Here we explored whether action observation alone can induce automatic locomotor adaptation in humans. To explore this possibility, we used the "broken escalator" paradigm. Conventionally this involves stepping upon a stationary sled after having previously experienced it actually moving (Moving trials). This history of motion produces a locomotor aftereffect when subsequently stepping onto a stationary sled. We found that viewing an actor perform the Moving trials was sufficient to generate a locomotor aftereffect in the observer, the size of which was significantly correlated with the size of the movement (postural sway) observed. Crucially, the effect is specific to watching the task being performed, as no motor adaptation occurs after simply viewing the sled move in isolation. These findings demonstrate that locomotor adaptation in humans can be driven purely by action observation, with the brain adapting motor plans in response to the size of the observed individual's motion. This mechanism may be mediated by a mirror neuron system that automatically adapts behavior to minimize movement errors and improve motor skills through social cues, although further neurophysiological studies are required to support this theory. These data suggest that merely observing the gait of another person in a challenging environment is sufficient to generate appropriate postural countermeasures, implying the existence of an automatic mechanism for adapting locomotor behavior.
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Mitesh
authors.initials: M
authors.lastname: Patel
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: R Edward
authors.identifier: http://orcid.org/0000-0002-3656-5906
authors.initials: RE
authors.lastname: Roberts
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Mohammed U
authors.initials: MU
authors.lastname: Riyaz
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Maroof
authors.initials: M
authors.lastname: Ahmed
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: David
authors.initials: D
authors.lastname: Buckwell
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Karen
authors.initials: K
authors.lastname: Bunday
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Hena
authors.initials: H
authors.lastname: Ahmad
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Diego
authors.initials: D
authors.lastname: Kaski
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and.
authors.forename: Qadeer
authors.initials: Q
authors.lastname: Arshad
authors.affiliation: Department of Neuro-otology, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, London, United Kingdom; and a.bronstein@imperial.ac.uk.
authors.forename: Adolfo M
authors.initials: AM
authors.lastname: Bronstein
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D005260:Female; D005366:Figural Aftereffect; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D011597:Psychomotor Performance
keywords: action observation; adaptation; learning; locomotion; mirror neurons