title: Do not resonate with actions: sentence polarity modulates cortico-spinal excitability during action-related sentence reading.
abstract: BACKGROUND
  Theories of embodied language suggest that the motor system is differentially called into action when processing motor-related versus abstract content words or sentences. It has been recently shown that processing negative polarity action-related sentences modulates neural activity of premotor and motor cortices.
  
  
  RESULTS
  We sought to determine whether reading negative polarity sentences brought about differential modulation of cortico-spinal motor excitability depending on processing hand-action related or abstract sentences. Facilitatory paired-pulses Transcranial Magnetic Stimulation (pp-TMS) was applied to the primary motor representation of the right-hand and the recorded amplitude of induced motor-evoked potentials (MEP) was used to index M1 activity during passive reading of either hand-action related or abstract content sentences presented in both negative and affirmative polarity. Results showed that the cortico-spinal excitability was affected by sentence polarity only in the hand-action related condition. Indeed, in keeping with previous TMS studies, reading positive polarity, hand action-related sentences suppressed cortico-spinal reactivity. This effect was absent when reading hand action-related negative polarity sentences. Moreover, no modulation of cortico-spinal reactivity was associated with either negative or positive polarity abstract sentences.
  
  
  CONCLUSIONS
  Our results indicate that grammatical cues prompting motor negation reduce the cortico-spinal suppression associated with affirmative action sentences reading and thus suggest that motor simulative processes underlying the embodiment may involve even syntactic features of language.
authors.affiliation: Department of Psychology, University of Rome La Sapienza, Rome, Italy.
authors.forename: Marco Tullio
authors.initials: MT
authors.lastname: Liuzza
authors.forename: Matteo
authors.initials: M
authors.lastname: Candidi
authors.forename: Salvatore Maria
authors.initials: SM
authors.lastname: Aglioti
mesh_terms: D002540:Cerebral Cortex / Q000502:physiology*; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D011932:Reading; D013116:Spinal Cord / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation