J-P Orliaguet

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In two experiments, perceptual anticipation--that is, the observer's ability to predict the course of dynamic visual events--in the case of handwriting traces was investigated. Observers were shown the dynamic display of the middle letter l excerpted from two cursive trigrams (lll or lln) handwritten by one individual. The experimental factor was the(More)
A large body of psychophysical evidence suggests that perception of human movement is constrained by the observer's motor competence. PET measurements of regional cerebral blood flow were performed in eight healthy subjects who were requested, in a forced-choice paradigm, to anticipate the outcome of a single moving dot trajectory depicting the beginning of(More)
The execution of a graphemic sequence is constrained by spatial demands that result in fluctuations of letter shape and movement time. When producing two letters (ll, le, or ln) the movement time and the letter shape of the first letter depend on the execution constraints of the second one. The motor system thus anticipates the production of the forthcoming(More)
This study concerns the adaptation of motor system when the production of movement was visually controlled through a video display. The subjects had to perform a pointing movement in two visual-feedback conditions: they could see the displacement of their hand or only the final location of the hand on the videoscreen. By changing the zoom of the camera, the(More)
The aim of the present study was to show that planning and controlling the trajectory of a pointing movement is influenced not solely by physical constraints but also by visual constraints. Subjects were required to point towards different targets located at 20 degrees , 40 degrees , 60 degrees and 80 degrees of eccentricity. Movements were either(More)
A perceptual analysis of the French vowel [u] produced by 10 speakers under normal and perturbed conditions (Savariaux et al., 1995) is presented which aims at characterizing in the perceptual domain the task of a speaker for this vowel, and, then, at understanding the strategies developed by the speakers to deal with the lip perturbation. Identification(More)
The present experiment focused on spatial accuracy and kinematics of fast pointing movements submitted to a multi-directional inertial perturbation. Pointing movements were performed without direct visual control, on a rotating armchair adding centrifugal and Coriolis forces to the natural displacement of the arm. The simultaneous action of these two forces(More)
The aim of the present study is to show that the sensorimotor system makes a differential use of visual and internal (proprioception and efferent copy) signals when evaluating either the spatial or the dynamical components of our own motor response carried out under a remote visual feedback. Subjects were required to monitor target-directed pointings from(More)
In video-controlled tasks, visuomotor performance is generally initially poor with rotated visual display, but improves through trial-by-trial learning. We hypothesise that the inaccurate processing of the visual hand-to-target vector mainly results from the persistent influence of non-visual information relating to arm posture. To test this hypothesis,(More)