Dataset Information

Detection of deceptive motions in rugby from visual motion cues.

ABSTRACT: Frequently, in rugby, players incorporate deceptive motions (e.g., a side-step) in order to pass their opponent. Previous works showed that expert defenders are more efficient in detecting deceptive motions. Performance was shown to be correlated with the evolution of the center of gravity of the attacker, suggesting that experts may rely on global motion cues. This study aims at investigating whether a representation of center of gravity can be useful for training purposes, by using this representation alone or by combining it with the local motion cues given by body parts. We designed an experiment in virtual reality to control the motion cues available to the defenders. Sixteen healthy participants (seven experts and nine novices) acted as defenders while a virtual attacker approached. Participants completed two separate tasks. The first was a time occlusion perception task, occlusion after 100ms, 200ms or 300ms after the initial change in direction, thereafter participants indicated the passing direction of the attacker. The second was a perception-action task, participants were instructed to intercept the oncoming attacker by displacing medio-laterally. The attacker performed either a non-deceptive motion, directly toward the final passing direction or a deceptive motion, initially toward a false direction before quickly reorienting to the true direction. There was a main effect of expertise, appearance, cut off times and motion on correct responses during both tasks. There was an interaction between visual appearance and expertise, and between motion type and expertise during the perception task, however, this interaction was not present during the perception-action task. We observed that experts maintained superiority in the perception of deceptive motion; however when the visual appearance is reduced to global motion alone the difference between novices and experts is reduced. We further explore the interactions and discuss the effects observed for the visual appearance and expertise.

SUBMITTER: Lynch SD

PROVIDER: S-EPMC6743770 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Detection of deceptive motions in rugby from visual motion cues.

Lynch Sean Dean SD Olivier Anne-Hélène AH Bideau Benoit B Kulpa Richard R

PloS one 20190913 9

Frequently, in rugby, players incorporate deceptive motions (e.g., a side-step) in order to pass their opponent. Previous works showed that expert defenders are more efficient in detecting deceptive motions. Performance was shown to be correlated with the evolution of the center of gravity of the attacker, suggesting that experts may rely on global motion cues. This study aims at investigating whether a representation of center of gravity can be useful for training purposes, by using this repres ...[more]

PMID: 31518358

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Project description:Parkinson's disease is prototypically a movement disorder. Although perceptual and motor functions are highly interdependent, much less is known about perceptual deficits in Parkinson's disease, which are less observable by nature, and might go unnoticed if not tested directly. It is therefore imperative to seek and identify these, to fully understand the challenges facing patients with Parkinson's disease. Also, perceptual deficits may be related to motor symptoms. Posture, gait and balance, affected in Parkinson's disease, rely on veridical perception of one's own motion (self-motion) in space. Yet it is not known whether self-motion perception is impaired in Parkinson's disease. Using a well-established multisensory paradigm of heading discrimination (that has not been previously applied to Parkinson's disease), we tested unisensory visual and vestibular self-motion perception, as well as multisensory integration of visual and vestibular cues, in 19 Parkinson's disease, 23 healthy age-matched and 20 healthy young-adult participants. After experiencing vestibular (on a motion platform), visual (optic flow) or multisensory (combined visual-vestibular) self-motion stimuli at various headings, participants reported whether their perceived heading was to the right or left of straight ahead. Parkinson's disease participants and age-matched controls were tested twice (Parkinson's disease participants on and off medication). Parkinson's disease participants demonstrated significantly impaired visual self-motion perception compared with age-matched controls on both visits, irrespective of medication status. Young controls performed slightly (but not significantly) better than age-matched controls and significantly better than the Parkinson's disease group. The visual self-motion perception impairment in Parkinson's disease correlated significantly with clinical disease severity. By contrast, vestibular performance was unimpaired in Parkinson's disease. Remarkably, despite impaired visual self-motion perception, Parkinson's disease participants significantly overweighted the visual cues during multisensory (visual-vestibular ) integration (compared with Bayesian predictions of optimal integration) and significantly more than controls. These findings indicate that self-motion perception in Parkinson's disease is affected by impaired visual cues and by suboptimal visual-vestibular integration (overweighting of visual cues). Notably, vestibular self-motion perception was unimpaired. Thus, visual self-motion perception is specifically impaired in early-stage Parkinson's disease. This can impact Parkinson's disease diagnosis and subtyping. Overweighting of visual cues could reflect a general multisensory integration deficit in Parkinson's disease, or specific overestimation of visual cue reliability. Finally, impaired self-motion perception in Parkinson's disease may contribute to impaired balance and gait control. Future investigation into this connection might open up new avenues of alternative therapies to better treat these difficult symptoms.

Dataset Information

Detection of deceptive motions in rugby from visual motion cues.

Publications

Detection of deceptive motions in rugby from visual motion cues.

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