title: Cortico-spinal embodiment of newly acquired, action-related semantic associations.
abstract: BACKGROUND
  Behavioral and neurophysiological studies indicate that the semantic derivation of the motor skills of a given model (e.g., famous tennis or soccer athlete) modulates the reactivity of arm and leg cortico-spinal representations of an onlooker who performs a categorization task. Information on the possible plastic nature of the sensorimotor mapping of action-related knowledge is still lacking.
  
  
  OBJECTIVE
  Here we explored the time course of any cortico-spinal excitability modulation induced by the creation of arbitrary associations between a personal name and tennis- or soccer-related motor skills.
  
  
  METHODS
  We recorded the amplitude of Transcranial Magnetic Stimulation (TMS) Motor Evoked Potentials (MEPs) from arm and leg muscles during a categorization task concerning names that were learned in association with either soccer players, tennis players or control, non-motor, identities (actors). We stimulated the cortico-spinal system and recorded the MEPs at three different time points (0-24-72 h) after the association learning.
  
  
  RESULTS
  Coherently with previous literature we found a relative dissociation of leg muscles MEPs during reading of soccer-associated personal names with respect to tennis ones. Importantly this modulation was measured only 72 h after having learned the association. This effect was not found in the arm muscle.
  
  
  CONCLUSIONS
  The results suggest that for the process of embodying semantic associations in the motor system to take place, the strength of the association itself needs to rise above some level of consolidation.
authors.affiliation: Department of Psychology, University of Rome "La Sapienza", Rome, Italy; IRCCS, Santa Lucia Foundation, Rome, Italy; School of Psychology, The University of Queensland, St. Lucia, Australia. Electronic address: carmelo.vicario@uniroma1.it.
authors.forename: Carmelo Mario
authors.initials: CM
authors.lastname: Vicario
authors.forename: Matteo
authors.initials: M
authors.lastname: Candidi
authors.forename: Salvatore Maria
authors.initials: SM
authors.lastname: Aglioti
mesh_terms: D000328:Adult; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Embodied cognition; Memory consolidation; Motor evoked potentials; Semantic learning; TMS