Observing Grasping Actions Directed to Emotion-Laden Objects: Effects upon Corticospinal Excitability.
The motor system is recruited whenever one executes an action as well as when one observes the same action being executed by others. Although it is well established that emotion modulates the motor system, the effect of observing other individuals acting in an emotional context is particularly elusive. The main aim of this study was to investigate the effect induced by the observation of grasping directed to emotion-laden objects upon corticospinal excitability (CSE). Participants classified video-clips depicting the right-hand of an actor grasping emotion-laden objects. Twenty video-clips differing in terms of valence but balanced in arousal level were selected. Motor evoked potentials (MEPs) were then recorded from the first dorsal interosseous using transcranial magnetic stimulation (TMS) while the participants observed the selected emotional video-clips. During the video-clip presentation, TMS pulses were randomly applied at one of two different time points of grasping: (1) maximum grip aperture, and (2) object contact time. CSE was higher during the observation of grasping directed to unpleasant objects compared to pleasant ones. These results indicate that when someone observes an action of grasping directed to emotion-laden objects, the effect of the object valence promotes a specific modulation over the motor system.
Department of Physiology, Federal University of Juiz de Fora Minas Gerais, Brazil.
Anaelli A
AA
Nogueira-Campos
Laboratory of Motor Cognition, Department of Anatomy, Federal University of Pará Belém, Brazil.
Ghislain
G
Saunier
IFIBIO Houssay, Department of Physiology and Biophysics, School of Medicine, University of Buenos Aires Buenos Aires, Argentina.
Valeria
V
Della-Maggiore
Post-Graduate Program in Rehabilitation Sciences, Unisuam Rio de Janeiro, Brazil.
Laura A S
LA
De Oliveira
Post-Graduate Program in Rehabilitation Sciences, Unisuam Rio de Janeiro, Brazil.
Erika C
EC
Rodrigues
Laboratory of Neurobiology II, Neurobiology Program, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Instituto de Neurologia Deolindo Couto, Federal University of Rio de JaneiroRio de Janeiro, Brazil.
Claudia D
CD
Vargas
goal-directed actions; mirror neurons; motor evoked potentials; motor resonance; valence