title: Effect of weight-related labels on corticospinal excitability during observation of grasping: a TMS study.
abstract: Recent studies of corticospinal excitability during observation of grasping and lifting of objects of different weight have highlighted the role of agent's kinematics in modulating observer's motor excitability. Here, we investigate whether explicit weight-related information, provided by written labels on the objects, modulate the excitability of the observer's motor system and how this modulation is affected when there is a conflict between label and object's weight. We measured TMS-evoked motor potentials (MEPs) from right hand intrinsic muscles, while subjects were observing an actor lifting objects of different weights, in some trials labeled (heavy/light) in congruent or incongruent way. Results confirmed a weight-related modulation of MEPs based on kinematic cues. Interestingly, any conflict between the labels and the actual weight (i.e., explicit versus implicit information), although never consciously noticed by the observer, deeply affected the mirroring of others' actions. Our findings stress the automatic involvement of the mirror-neuron system.
authors.affiliation: DSBTA Section of Human Physiology, University of Ferrara, Via Fossato di Mortara 17/19, 44100 Ferrara, Italy.
authors.forename: Patrice
authors.initials: P
authors.lastname: Senot
authors.forename: Alessandro
authors.initials: A
authors.lastname: D'Ausilio
authors.forename: Michele
authors.initials: M
authors.lastname: Franca
authors.forename: Luana
authors.initials: L
authors.lastname: Caselli
authors.forename: Laila
authors.initials: L
authors.lastname: Craighero
authors.forename: Luciano
authors.initials: L
authors.lastname: Fadiga
mesh_terms: D000328:Adult; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D017770:Lifting; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D014891:Weight Lifting / Q000502:physiology; D055815:Young Adult