title: The influence of scopolamine on motor control and attentional processes.
abstract: BACKGROUND
  Motion sickness may be caused by a sensory conflict between the visual and the vestibular systems. Scopolamine, known to be the most effective therapy to control the vegetative symptoms of motion sickness, acts on the vestibular nucleus and potentially the vestibulospinal pathway, which may affect balance and motor tasks requiring both attentional process and motor balance. The aim of this study was to explore the effect of scopolamine on motor control and attentional processes.
  
  
  METHODS
  Seven subjects were evaluated on four different tasks before and after a subcutaneous injection of scopolamine (0.2 mg): a one-minute balance test, a subjective visual vertical test, a pointing task and a galvanic vestibular stimulation with EMG recordings.
  
  
  RESULTS
  The results showed that the reaction time and the movement duration were not modified after the injection of scopolamine. However, there was an increase in the center of pressure displacement during the balance test, a decrease in EMG muscle response after galvanic vestibular stimulation and an alteration in the perception of verticality.
  
  
  CONCLUSIONS
  These results confirm that low doses of scopolamine such as those prescribed to avoid motion sickness have no effect on attentional processes, but that it is essential to consider the responsiveness of each subject. However, scopolamine did affect postural control and the perception of verticality. In conclusion, the use of scopolamine to prevent motion sickness must be considered carefully because it could increase imbalances in situations when individuals are already at risk of falling (e.g., sailing, parabolic flight).
authors.affiliation: Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287 CNRS, Université de Bordeaux , Bordeaux , France.
authors.forename: Emma
authors.initials: E
authors.lastname: Bestaven
authors.affiliation: Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287 CNRS, Université de Bordeaux , Bordeaux , France.
authors.forename: Charline
authors.initials: C
authors.lastname: Kambrun
authors.affiliation: Institut des Maladies Neurodégénératives, UMR 5293 CNRS, Université de Bordeaux, Bordeaux, France; Service d'explorations fonctionnelles du système nerveux, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Guehl
authors.affiliation: Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287 CNRS, Université de Bordeaux , Bordeaux , France.
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Cazalets
authors.affiliation: Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287 CNRS, Université de Bordeaux , Bordeaux , France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Guillaud
keywords: Attentional processes; EMG; GVS; Motion sickness; Parabolic flights; Postural control; Scopolamine