title: Preparing to grasp emotionally laden stimuli.
abstract: BACKGROUND
  Contemporary theories of motor control propose that motor planning involves the prediction of the consequences of actions. These predictions include the associated costs as well as the rewarding nature of movements' outcomes. Within the estimation of these costs and rewards would lie the valence, that is, the pleasantness or unpleasantness of a given stimulus with which one is about to interact. The aim of this study was to test if motor preparation encompasses valence.
  
  
  RESULTS
  The readiness potential, an electrophysiological marker of motor preparation, was recorded before the grasping of pleasant, neutral and unpleasant stimuli. Items used were balanced in weight and placed inside transparent cylinders to prompt a similar grip among trials. Compared with neutral stimuli, the grasping of pleasant stimuli was preceded by a readiness potential of lower amplitude, whereas that of unpleasant stimuli was associated with a readiness potential of higher amplitude.
  
  
  CONCLUSIONS
  We show for the first time that the sensorimotor cortex activity preceding the grasping of a stimulus is affected by its valence. Smaller readiness potential amplitudes found for pleasant stimuli could imply in the recruitment of pre-set motor repertoires, whereas higher amplitudes found for unpleasant stimuli would emerge from a discrepancy between the required action and their aversiveness. Our results indicate that the prediction of action outcomes encompasses an estimate of the valence of a stimulus with which one is about to interact.
authors.affiliation: Laboratório de Neurobiologia II, Programa de Neurobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil.
authors.forename: Laura Alice Santos
authors.initials: LA
authors.lastname: de Oliveira
authors.forename: Luís Aureliano
authors.initials: LA
authors.lastname: Imbiriba
authors.forename: Maitê Mello
authors.initials: MM
authors.lastname: Russo
authors.forename: Anaelli A
authors.initials: AA
authors.lastname: Nogueira-Campos
authors.forename: Erika de C
authors.initials: Ede C
authors.lastname: Rodrigues
authors.forename: Mirtes G
authors.initials: MG
authors.lastname: Pereira
authors.forename: Eliane
authors.initials: E
authors.lastname: Volchan
authors.forename: Cláudia Domingues
authors.initials: CD
authors.lastname: Vargas
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology; D004569:Electroencephalography; D004644:Emotions / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D055815:Young Adult