Gaze fixation improves the stability of expert juggling

Novice and expert jugglers employ different visuomotor strategies: whereas novices look at the balls around their zeniths, experts tend to fixate their gaze at a central location within the pattern (so-called gaze-through). A gaze-through strategy may reflect visuomotor parsimony, i.e., the use of simpler visuomotor (oculomotor and/or attentional) strategies as afforded by superior tossing accuracy and error corrections. In addition, the more stable gaze during a gaze-through strategy may result in more accurate movement planning by providing a stable base for gaze-centered neural coding of ball motion and movement plans or for shifts in attention. To determine whether a stable gaze might indeed have such beneficial effects on juggling, we examined juggling variability during 3-ball cascade juggling with and without constrained gaze fixation (at various depths) in expert performers (n = 5). Novice jugglers were included (n = 5) for comparison, even though our predictions pertained specifically to expert juggling. We indeed observed that experts, but not novices, juggled significantly less variable when fixating, compared to unconstrained viewing. Thus, while visuomotor parsimony might still contribute to the emergence of a gaze-through strategy, this study highlights an additional role for improved movement planning. This role may be engendered by gaze-centered coding and/or attentional control mechanisms in the brain

La codification en Belgique :le droit de la consommation dans le nouveau Code de droit économique: in n L. Arcelin Lécuyer (éd.), Quels moyens pour un droit de la consommation effectif et efficace à l’ère numérique ?

Cet article, rédigé suite à un colloque international tenu à l’Université de La Rochelle le 10 octobre 2014 ( intervention consultable ici :http://portail-video.univ-lr.fr/La-pertinence-d-un-code-de-la), a pour objet de montrer et analyser l’approche suivie en droit belge dans le domaine de la codification du droit de la consommation. Cette approche a plusieurs particularités :au contraire de pays comme l’Allemagne, les Pays-Bas ou l’Autriche, la Belgique a d’emblée régi le droit de la consommation en-dehors Code civil ;mais, par ailleurs, au contraire d’autres Etats membres de l’Union européenne, comme la France, elle n’a pas non plus fait le choix de l’adoption d’un Code propre au droit de la consommation. Depuis l’origine (récente) de ce droit en Belgique, le législateur régit en un seul corps de texte le droit de la concurrence déloyale (les normes de loyauté dans les rapports entre professionnels), d’une part, et le droit de la consommation (normes d’information et de protection des consommateurs), de l’autre, ce qui présente des avantages mais pose aussi des problèmes aigus lors de la transposition des directives européennes lorsque celles-ci ne concernent que le droit de la consommation.info:eu-repo/semantics/publishe

Interactions between new and pre-existing dynamics in bimanual movement control

Motor skills are commonly acquired through practice. This process not only involves acquisition of the particular task demands but also requires overcoming pre-existing modes. In the present study, interactions between new and intrinsic dynamics were evaluated. Accordingly, bimanual finger tapping with a 2:1 ratio was performed according to two training schedules: continuous (consecutive trials) and interrupted (non-consecutive trials with intermediate 1:1 in-phase performances). In addition, in-phase and anti-phase were probed before and after training. Behavioural output was assessed by means of temporal accuracy and variability, whereas neural activation patterns were determined by EEG coherence. Results showed that continuous practice resulted in improved performance with reduced coherence across the motor network. For interrupted practice, behavioural execution ameliorated, although it was inferior to performance with continuous practice. In terms of neural changes, the degree of intrahemispheric and midline connectivity did not reduce with interrupted practice, whereas interhemispheric connectivity increased. This signifies that short-term motor consolidation of the 2:1 task was disrupted due to intermediate performance of the in-phase mode. Furthermore, the probed in-phase and anti-phase pattern showed no behavioural changes, although neural alterations occurred that depended on training schedule and coordination mode. Overall, the observations illustrate bidirectional interactions between new and inherent dynamics during motor acquisition, raising issues about effective methods for learning skills and scheduling of practices in neurorehabilitation