Attentional Demands of Movement Observation as Tested by a Dual Task Approach

Movement observation (MO) has been shown to activate the motor cortex of the observer as indicated by an increase of corticomotor excitability for muscles involved in the observed actions. Moreover, behavioral work has strongly suggested that this process occurs in a near-automatic manner. Here we further tested this proposal by applying transcranial magnetic stimulation (TMS) when subjects observed how an actor lifted objects of different weights as a single or a dual task. The secondary task was either an auditory discrimination task (experiment 1) or a visual discrimination task (experiment 2). In experiment 1, we found that corticomotor excitability reflected the force requirements indicated in the observed movies (i.e. higher responses when the actor had to apply higher forces). Interestingly, this effect was found irrespective of whether MO was performed as a single or a dual task. By contrast, no such systematic modulations of corticomotor excitability were observed in experiment 2 when visual distracters were present. We conclude that interference effects might arise when MO is performed while competing visual stimuli are present. However, when a secondary task is situated in a different modality, neural responses are in line with the notion that the observers motor system responds in a near-automatic manner. This suggests that MO is a task with very low cognitive demands which might be a valuable supplement for rehabilitation training, particularly, in the acute phase after the incident or in patients suffering from attention deficits. However, it is important to keep in mind that visual distracters might interfere with the neural response in M1

The effects of enhanced visual feedback on human synchronization

The execution of actions not only reposes on the spatial and temporal organization of the movements as such but also on their appropriate imbedding into the environmental spatio-temporal constraints. Actually, performance outcome appears to be strongly influenced by the strength of the perception-action coupling. The present experiment wants to examine to what degree this coupling strength affects the spatial and spatio-temporal characteristics of a synchronization task. In particular, the effects of: (i) enhanced visual feedback; and (ii) a modification in the spatial organization of the task were investigated. To do so, a task was designed in which horizontal arm movements had to be synchronized with a target light moving horizontally or vertically at a sinusoidal speed. Subjects performed six experimental conditions representing three synchronization modes (horizontal in-phase, horizontal anti-phase and orthogonal) and two feedback conditions (no feedback and feedback). The results for movement amplitude and relative phase revealed the operation of task specific effects. Apparently, the availability of feedback at the perception-action coupling level provoked the use of different strategies to cope with the constraints of this synchronization task.status: publishe

The effects of a student-centered versus teacher-centered teaching approach on tactical learning outcomes: a volleyball case

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Synchronising horizontal arm movement with transparent motion

The relationship between perception and motor performance was studied in a situation that required perceptual processing of a complex motion stimulus in which a target signal had to be segmented, selected, and tracked. Participants were asked to move their arm in synchrony with one surface of a transparent motion display in which two surfaces moved horizontally back-and-forth over each other. The quality of tracking performance was measured as a function of bottom-up and top-down perceptual cues and their interplay. Target signal strength was manipulated by lowering the relative amount of signal dots constituting the target, i.e., the coherence level (100%-50%-30%-10%; the distractor surface was always 100% coherent). A colour cue that distinguished the target from the distractor surface was either available or absent. In the presence of a colour cue, participants experienced little or no difficulties at coherence levels of 50%-100% but when surface formation was complicated by lowering the coherence level, synchronisation consistency decreased. This corresponds with continuous attempts, successful and unsuccessful, to correct inaccurate synchronisation. In the absence of a colour cue, difficulties were frequently observed in all coherence conditions, but they differed depending on the coherence level. Overall, these results suggest that colour can serve as a strong top-down cue for proper target selection and tracking, provided that bottom-up motion signals are sufficiently strong.status: publishe

The integration of the motion coherence paradigm in a synchronization task at the perception-action level

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The influence of motion coherence manipulations on the synchronization level of a perception-action task

The present experiment was conducted to examine the integration of the motion coherence paradigm in a synchronization task. Random-dot kinematograms were used to generate a pattern of oscillating dots representing four different coherence levels (10%, 30%, 50% and 100%) and one target-alone condition. The participants had to synchronize their arm with the coherently moving dots according to two different synchronization modes (in-phase and anti-phase). The results revealed a substantial performance decline when the target/noise ratio dropped under the critical threshold situated around the 30% coherence level, albeit independent of the synchronization mode. In general, these findings highlighted the impact of the perception of motion based on the level of motion coherence in the visual signal on the synchronization behavior in a perception-action setting.status: publishe

The influence of different training programs on the synchronization of an arm movement to external events in older men

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Perceived justice of the coach predicts satisfaction and intrinsic motivation in handball and volleyball

Perceived justice was broadly highlighted in organizational settings as an important determinant of the employees’ performance, intrinsic motivation and satisfaction. Since sport teams and organizations had many characteristics in common, it seemed likely that perceived justice would have a valuable influence in a sport context. For this reason, we aimed to examine the impact of the perceived justice of the coach on team athletes’ intrinsic motivation and satisfaction, in a longitudinal way. Additionally, we were interested in the influence of coach’s transparency, team identification, social cohesion and task cohesion as predictor variables. A questionnaire was filled in by 91 Belgian top handball and volleyball players to asses the different variables during 5 consecutive matches. Regression analyses were conducted to explore the variance of athletes’ intrinsic motivation and satisfaction that could be explained by the variance of the predictor variables, (i.e., perceived justice, coach’s transparency, team identification, social cohesion and task cohesion). The amount of variance that could be explained by the predictor variables fluctuated between 40% (match 1) and 69% (match 3) for the athletes’ intrinsic motivation and between 38% (match 1) and 60% (match 5) for their satisfaction. Furthermore, our results revealed that perceived justice of the coach by the athletes was the only predictor variable with a significant contribution on the athletes’ intrinsic motivation (p<0.001) and satisfaction (p<0.005) for every match. These findings clearly accentuated the importance of perceived justice since it was the most determinant predictor variable of the satisfaction and the intrinsic motivation of team athletes.status: publishe