Jean-pierre Orliaguet - Academia.edu (original) (raw)
Papers by Jean-pierre Orliaguet
Neuroscience Letters, 2004
The aim of the present study was to show that planning and controlling the trajectory of a pointi... 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 • , 40 • , 60 • and 80 • of eccentricity. Movements were either constrained (i.e. two-dimensional movements) or unconstrained (i.e. three-dimensional movements). Furthermore, movements were carried out either under a direct or a remote visual control (use of a video system). Results revealed that trajectories of constrained movements were nearly straight whatever the eccentricity of the target and the type of visual control. A different pattern was revealed for unconstrained movements. Indeed, under direct vision the trajectory curvature increased as the eccentricity augmented, whereas under indirect vision, trajectories remained nearly straight whatever the eccentricity of the target. Thus, movements controlled through a remote visual feedback appear to be planned in extrinsic space as constrained movements.
Many applications use electrostimulation of the human skin to provide tactile sensation. The effe... more Many applications use electrostimulation of the human skin to provide tactile sensation. The effect of electrotactile stimulations were studied on a 6x6 matrix of tactile electrodes placed on the anterior part of the tongue. The liminary threshold with continuous or discontinuous waveform and patterns with 2 or 4 electrodes was investigated.
Performing minimal-invasive surgical punctures require guiding a needle toward an intracorporeal ... more Performing minimal-invasive surgical punctures require guiding a needle toward an intracorporeal clinically-defined target. As this technique does not involve cutting the body open, a visualization system is employed to provide the surgeon with indirect visual spatial information about the intracorporeal positions of the tool. One may consider that such systems reduce the ergonomics of the situation as they generate a
Human Movement Science, 1997
The purpose of the study was to understand how force is controlled for impact movements such as g... more The purpose of the study was to understand how force is controlled for impact movements such as golf putting. Expert players (10) and control subjects (10) executed a putt as accurately as possible, in order to reach a target distance of 1, 2, 3, or 4 m. Movements of the club were recorded at 200 Hz via a SELSPOT system.
Perception, 2000
first demonstrated that observers use motor knowledge when decoding static handwritten material. ... more first demonstrated that observers use motor knowledge when decoding static handwritten material. showed that the spatial distortions produced during movement execution provide information on the direction of the motor sequence and stroke order. This information is exploited during the recognition of artificial characters. Furthermore, knowledge of the underlying production method is particularly relevant for character discrimination . In the recognition of Chinese logograms, perceptual processes are also sensitive to stroke order, ie to information on the underlying motor sequence (Flores d'Arcais 1994). Moreover, palaeographers often use the information provided by the upstrokes and downstrokes followed by the scribe's pen (the ductus) for deciphering ancient texts . When a character is difficult to read, this information enables the palaeographer to infer the movement the scribe executed to trace it. The analysis of movement trajectory constitutes the means by which the character is identified. These studies therefore show the importance of motor information in the perception of static graphic material. Other studies on the visual perception of dynamic graphic material confirm that visual processes can use motor information. Drawing movements follow a systematic relation between movement velocity and the geometry of its trajectory . Thus, a circle is drawn at constant velocity whereas the velocity of the graphic movement when drawing an ellipse decreases in the curved regions and increases in the more linear ones. showed that spotlights tracing circles were perceived as tracing ellipses when the kinematics of the presented movements corresponded to those of a human drawing ellipses. Detecting anticipatory events in handwriting movements À Perception, 2000, volume 29, pages 953^964 Abstract. We investigated how visual processes exploit specific anticipatory movements observed in handwriting gestures. Previous research has shown that the kinematic information contained in the downstroke of an l is exploited to predict the identity of the forthcoming letter. Here, we determined the moment at which prediction takes place. Two between-letter effects were examined: changes in size (ll vs le) and changes in rotation direction (le vs ln). Results show that with only 75% of the l downstroke trajectory (or 60% of the downstroke time) subjects are already capable of predicting the identity of the letter following the l, that is well before the end of the downstroke. Analysis also reveals that identification takes place after the presentation of the movement acceleration phase. The visual perception of motor anticipation seems to involve the detection of motor events.
Perception, 2005
Studies of movement production have shown that the relationship between the amplitude of a moveme... more Studies of movement production have shown that the relationship between the amplitude of a movement and its duration varies according to the type of gesture. In the case of pointing movements the duration increases as a function of distance and width of the target (Fitts' law), whereas for writing movements the duration tends to remain constant across changes in trajectory length (isochrony principle). We compared the visual perception of these two categories of movement. The participants judged the speed of a light spot that portrayed the motion of the end-point of a hand-held pen (pointing or writing). For the two types of gesture we used 8 stimulus sizes (from 2.5 cm to 20 cm) and 32 durations (from 0.2 s to 1.75 s). Viewing each combination of size and duration, participants had to indicate whether the movement speed seemed "fast", "slow", or "correct". Results showed that the participants' perceptual preferences were in agreement with the rules of movement production. The stimulus size was more influential in the pointing condition than in the writing condition. We consider that this finding reflects the influence of common representational resources for perceptual judgment and movement production.
Neuroscience Letters, 2008
The aim of this experiment was to show that the visual preference for isochronic movements does n... more The aim of this experiment was to show that the visual preference for isochronic movements does not nessesarily imply a motor simulation and therefore, does not depend on the kinematics of the perceived movement. To demonstrate this point, the participants' task was to adjust the velocity (the period) of a dot that depicted an elliptic motion with different perimeters (from 3 to 60 cm). The velocity profile of the movement conformed ("natural motions") or not ("unnatural motions") to the law of co-variation velocity-curvature (two-thirds power law), which is usually observed in the production of elliptic movements. For each condition, we evaluated the isochrony principle, i.e., the tendency to prefer constant durations of movement irrespective to changes in the trajectory perimeter. Our findings indicate that isochrony principle was observed whatever the kinematics of the movement (natural or unnatural). Therefore, they suggest that the perceptive preference for isochronic movements does not systematically imply a motor simulation.
Neuroscience Letters, 2008
Neuroreport, 2001
A large body of psychophysical evidence suggests that perception of human movement is constrained... 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¯ow 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 either mechanical, pointing, or writing movements. Selective activation of the left premotor cortex and of the right intraparietal sulcus was associated with visual anticipation of pointing movements while the left frontal operculum and superior parietal lobule were found to be activated during anticipation of writing movements. These results are discussed in the perspective that the motor system is part of a simulation network, which is used to interpret perceived actions.
The Journal of the Acoustical Society of America, 1993
![Research paper thumbnail of Compensation strategies for the perturbation of French [u] using a lip tube. II. Perceptual analysis](https://attachments.academia-assets.com/44860627/thumbnails/1.jpg)
](The Journal of the Acoustical Society of America, 1999
A perceptual analysis of the French vowel ͓u͔ produced by 10 speakers under normal and perturbed ... more A perceptual analysis of the French vowel ͓u͔ produced by 10 speakers under normal and perturbed conditions ͑Savariaux et al., 1995͒ 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 and rating tests showed that the French ͓u͔ is perceptually fairly well described in the ͓F1,(F2 -F0)͔ plane, and that the parameter (((F2 -F0)ϩF1)/2) ͑all frequencies in bark͒ provides a good overall correlate of the ''grave'' feature classically used to describe the vowel ͓u͔ in all languages. This permitted reanalysis of the behavior of the speakers during the perturbation experiment. Three of them succeed in producing a good ͓u͔ in spite of the lip tube, thanks to a combination of limited changes on F1 and (F2 -F0), but without producing the strong backward movement of the tongue, which would be necessary to keep the ͓F1,F2͔ pattern close to the one measured in normal speech. The only speaker who strongly moved his tongue back and maintained F1 and F2 at low values did not produce a perceptually well-rated ͓u͔, but additional tests demonstrate that this gesture allowed him to preserve the most important phonetic features of the French ͓u͔, which is primarily a back and rounded vowel. It is concluded that speech production is clearly guided by perceptual requirements, and that the speakers have a good representation of them, even if they are not all able to meet them in perturbed conditions.
IEEE Transactions on Biomedical Engineering, 2000
Human Movement Science, 2011
Deep stimulation of the sub-thalamic nucleus a b s t r a c t
Ergonomics, 2002
The present study (N=56) investigated spatio-temporal accuracy of reaching movements controlled v... more The present study (N=56) investigated spatio-temporal accuracy of reaching movements controlled visually through a video monitor. Direct vision of the hand was precluded and the direction of hand trajectory, as perceived on the video screen, was varied by changing the angle of the camera. The orientation of the visual scene displayed on the fronto-parallel plane was thus congruent (0° condition) or non-congruent (directional bias of 15°, 30° or 45° counterclockwise) according to the horizontal working space. The goal of this study was to determine whether local learning of a directional bias can be transferred to other locations in the working space, but taking into account the magnitude of the directional bias (15°, 30° or 45°), and the position of the successive objectives (targets at different distances (TDD) or different azimuths (TDA)).
Cortex, 2011
Action editor Naama Friedmann Published online xxx Keywords: Developmental mixed dyslexia Surface... more Action editor Naama Friedmann Published online xxx Keywords: Developmental mixed dyslexia Surface dysgraphia Visual attention span Reaching movements Length effect a b s t r a c t
Perception & Psychophysics, 2000
In two experiments, perceptual anticipation-that is, the observer's ability to predict the course... more 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 I excerpted from two cursive trigrams (lU or Un) handwritten by one individual. The experimental factor was the distribution of the velocity along the trace, which was controlled by a single parameter, {3. Only for one value of this parameter ({3 =2/3) did the display comply with the two-thirds power law, which describes how tangential velocity depends on curvature in writing movements. The task was to indicate the trigram from which the trace was excerpted-that is, to guess the letter that followed the specific instance of the I that had been displayed. In Experiment 1, the no answer option was available. Experiment 2 adopted a forced-choice response rule. Responses were never reinforced. When{3 =2/3,the rate of correct guesses was high (Experiment 1,PI correctJ = .69; Experiment 2, P(correctj = .78). The probability of a correct answer decreased significantly for both smaller and larger values of {3, with wrong answers becoming predominant at the extremes of the range of variation of this parameter. The results are consistent with the hypothesis that perceptual anticipation of human movements involves comparing the perceptual stimulus with an internal dynamic representation of the ongoing event.
Developmental Psychology, 2014
In human newborns, spontaneous visual preference for biological motion is reported to occur at bi... more In human newborns, spontaneous visual preference for biological motion is reported to occur at birth, but the factors underpinning this preference are still in debate. Using a standard visual preferential looking paradigm, 4 experiments were carried out in 3-day-old human newborns to assess the influence of translational displacement on perception of human locomotion. Experiment 1 shows that human newborns prefer a point-light walker display representing human locomotion as if on a treadmill over random motion. However, no preference for biological movement is observed in Experiment 2 when both biological and random motion displays are presented with translational displacement. Experiments 3 and 4 show that newborns exhibit preference for translated biological motion (Experiment 3) and random motion (Experiment 4) displays over the same configurations moving without translation. These findings reveal that human newborns have a preference for the translational component of movement independently of the presence of biological kinematics. The outcome suggests that translation constitutes the first step in development of visual preference for biological motion.
Neuroscience Letters, 2004
The aim of the present study was to show that planning and controlling the trajectory of a pointi... 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 • , 40 • , 60 • and 80 • of eccentricity. Movements were either constrained (i.e. two-dimensional movements) or unconstrained (i.e. three-dimensional movements). Furthermore, movements were carried out either under a direct or a remote visual control (use of a video system). Results revealed that trajectories of constrained movements were nearly straight whatever the eccentricity of the target and the type of visual control. A different pattern was revealed for unconstrained movements. Indeed, under direct vision the trajectory curvature increased as the eccentricity augmented, whereas under indirect vision, trajectories remained nearly straight whatever the eccentricity of the target. Thus, movements controlled through a remote visual feedback appear to be planned in extrinsic space as constrained movements.
Many applications use electrostimulation of the human skin to provide tactile sensation. The effe... more Many applications use electrostimulation of the human skin to provide tactile sensation. The effect of electrotactile stimulations were studied on a 6x6 matrix of tactile electrodes placed on the anterior part of the tongue. The liminary threshold with continuous or discontinuous waveform and patterns with 2 or 4 electrodes was investigated.
Performing minimal-invasive surgical punctures require guiding a needle toward an intracorporeal ... more Performing minimal-invasive surgical punctures require guiding a needle toward an intracorporeal clinically-defined target. As this technique does not involve cutting the body open, a visualization system is employed to provide the surgeon with indirect visual spatial information about the intracorporeal positions of the tool. One may consider that such systems reduce the ergonomics of the situation as they generate a
Human Movement Science, 1997
The purpose of the study was to understand how force is controlled for impact movements such as g... more The purpose of the study was to understand how force is controlled for impact movements such as golf putting. Expert players (10) and control subjects (10) executed a putt as accurately as possible, in order to reach a target distance of 1, 2, 3, or 4 m. Movements of the club were recorded at 200 Hz via a SELSPOT system.
Perception, 2000
first demonstrated that observers use motor knowledge when decoding static handwritten material. ... more first demonstrated that observers use motor knowledge when decoding static handwritten material. showed that the spatial distortions produced during movement execution provide information on the direction of the motor sequence and stroke order. This information is exploited during the recognition of artificial characters. Furthermore, knowledge of the underlying production method is particularly relevant for character discrimination . In the recognition of Chinese logograms, perceptual processes are also sensitive to stroke order, ie to information on the underlying motor sequence (Flores d'Arcais 1994). Moreover, palaeographers often use the information provided by the upstrokes and downstrokes followed by the scribe's pen (the ductus) for deciphering ancient texts . When a character is difficult to read, this information enables the palaeographer to infer the movement the scribe executed to trace it. The analysis of movement trajectory constitutes the means by which the character is identified. These studies therefore show the importance of motor information in the perception of static graphic material. Other studies on the visual perception of dynamic graphic material confirm that visual processes can use motor information. Drawing movements follow a systematic relation between movement velocity and the geometry of its trajectory . Thus, a circle is drawn at constant velocity whereas the velocity of the graphic movement when drawing an ellipse decreases in the curved regions and increases in the more linear ones. showed that spotlights tracing circles were perceived as tracing ellipses when the kinematics of the presented movements corresponded to those of a human drawing ellipses. Detecting anticipatory events in handwriting movements À Perception, 2000, volume 29, pages 953^964 Abstract. We investigated how visual processes exploit specific anticipatory movements observed in handwriting gestures. Previous research has shown that the kinematic information contained in the downstroke of an l is exploited to predict the identity of the forthcoming letter. Here, we determined the moment at which prediction takes place. Two between-letter effects were examined: changes in size (ll vs le) and changes in rotation direction (le vs ln). Results show that with only 75% of the l downstroke trajectory (or 60% of the downstroke time) subjects are already capable of predicting the identity of the letter following the l, that is well before the end of the downstroke. Analysis also reveals that identification takes place after the presentation of the movement acceleration phase. The visual perception of motor anticipation seems to involve the detection of motor events.
Perception, 2005
Studies of movement production have shown that the relationship between the amplitude of a moveme... more Studies of movement production have shown that the relationship between the amplitude of a movement and its duration varies according to the type of gesture. In the case of pointing movements the duration increases as a function of distance and width of the target (Fitts' law), whereas for writing movements the duration tends to remain constant across changes in trajectory length (isochrony principle). We compared the visual perception of these two categories of movement. The participants judged the speed of a light spot that portrayed the motion of the end-point of a hand-held pen (pointing or writing). For the two types of gesture we used 8 stimulus sizes (from 2.5 cm to 20 cm) and 32 durations (from 0.2 s to 1.75 s). Viewing each combination of size and duration, participants had to indicate whether the movement speed seemed "fast", "slow", or "correct". Results showed that the participants' perceptual preferences were in agreement with the rules of movement production. The stimulus size was more influential in the pointing condition than in the writing condition. We consider that this finding reflects the influence of common representational resources for perceptual judgment and movement production.
Neuroscience Letters, 2008
The aim of this experiment was to show that the visual preference for isochronic movements does n... more The aim of this experiment was to show that the visual preference for isochronic movements does not nessesarily imply a motor simulation and therefore, does not depend on the kinematics of the perceived movement. To demonstrate this point, the participants' task was to adjust the velocity (the period) of a dot that depicted an elliptic motion with different perimeters (from 3 to 60 cm). The velocity profile of the movement conformed ("natural motions") or not ("unnatural motions") to the law of co-variation velocity-curvature (two-thirds power law), which is usually observed in the production of elliptic movements. For each condition, we evaluated the isochrony principle, i.e., the tendency to prefer constant durations of movement irrespective to changes in the trajectory perimeter. Our findings indicate that isochrony principle was observed whatever the kinematics of the movement (natural or unnatural). Therefore, they suggest that the perceptive preference for isochronic movements does not systematically imply a motor simulation.
Neuroscience Letters, 2008
Neuroreport, 2001
A large body of psychophysical evidence suggests that perception of human movement is constrained... 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¯ow 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 either mechanical, pointing, or writing movements. Selective activation of the left premotor cortex and of the right intraparietal sulcus was associated with visual anticipation of pointing movements while the left frontal operculum and superior parietal lobule were found to be activated during anticipation of writing movements. These results are discussed in the perspective that the motor system is part of a simulation network, which is used to interpret perceived actions.
The Journal of the Acoustical Society of America, 1993
The Journal of the Acoustical Society of America, 1999
A perceptual analysis of the French vowel ͓u͔ produced by 10 speakers under normal and perturbed ... more A perceptual analysis of the French vowel ͓u͔ produced by 10 speakers under normal and perturbed conditions ͑Savariaux et al., 1995͒ 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 and rating tests showed that the French ͓u͔ is perceptually fairly well described in the ͓F1,(F2 -F0)͔ plane, and that the parameter (((F2 -F0)ϩF1)/2) ͑all frequencies in bark͒ provides a good overall correlate of the ''grave'' feature classically used to describe the vowel ͓u͔ in all languages. This permitted reanalysis of the behavior of the speakers during the perturbation experiment. Three of them succeed in producing a good ͓u͔ in spite of the lip tube, thanks to a combination of limited changes on F1 and (F2 -F0), but without producing the strong backward movement of the tongue, which would be necessary to keep the ͓F1,F2͔ pattern close to the one measured in normal speech. The only speaker who strongly moved his tongue back and maintained F1 and F2 at low values did not produce a perceptually well-rated ͓u͔, but additional tests demonstrate that this gesture allowed him to preserve the most important phonetic features of the French ͓u͔, which is primarily a back and rounded vowel. It is concluded that speech production is clearly guided by perceptual requirements, and that the speakers have a good representation of them, even if they are not all able to meet them in perturbed conditions.
IEEE Transactions on Biomedical Engineering, 2000
Human Movement Science, 2011
Deep stimulation of the sub-thalamic nucleus a b s t r a c t
Ergonomics, 2002
The present study (N=56) investigated spatio-temporal accuracy of reaching movements controlled v... more The present study (N=56) investigated spatio-temporal accuracy of reaching movements controlled visually through a video monitor. Direct vision of the hand was precluded and the direction of hand trajectory, as perceived on the video screen, was varied by changing the angle of the camera. The orientation of the visual scene displayed on the fronto-parallel plane was thus congruent (0° condition) or non-congruent (directional bias of 15°, 30° or 45° counterclockwise) according to the horizontal working space. The goal of this study was to determine whether local learning of a directional bias can be transferred to other locations in the working space, but taking into account the magnitude of the directional bias (15°, 30° or 45°), and the position of the successive objectives (targets at different distances (TDD) or different azimuths (TDA)).
Cortex, 2011
Action editor Naama Friedmann Published online xxx Keywords: Developmental mixed dyslexia Surface... more Action editor Naama Friedmann Published online xxx Keywords: Developmental mixed dyslexia Surface dysgraphia Visual attention span Reaching movements Length effect a b s t r a c t
Perception & Psychophysics, 2000
In two experiments, perceptual anticipation-that is, the observer's ability to predict the course... more 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 I excerpted from two cursive trigrams (lU or Un) handwritten by one individual. The experimental factor was the distribution of the velocity along the trace, which was controlled by a single parameter, {3. Only for one value of this parameter ({3 =2/3) did the display comply with the two-thirds power law, which describes how tangential velocity depends on curvature in writing movements. The task was to indicate the trigram from which the trace was excerpted-that is, to guess the letter that followed the specific instance of the I that had been displayed. In Experiment 1, the no answer option was available. Experiment 2 adopted a forced-choice response rule. Responses were never reinforced. When{3 =2/3,the rate of correct guesses was high (Experiment 1,PI correctJ = .69; Experiment 2, P(correctj = .78). The probability of a correct answer decreased significantly for both smaller and larger values of {3, with wrong answers becoming predominant at the extremes of the range of variation of this parameter. The results are consistent with the hypothesis that perceptual anticipation of human movements involves comparing the perceptual stimulus with an internal dynamic representation of the ongoing event.
Developmental Psychology, 2014
In human newborns, spontaneous visual preference for biological motion is reported to occur at bi... more In human newborns, spontaneous visual preference for biological motion is reported to occur at birth, but the factors underpinning this preference are still in debate. Using a standard visual preferential looking paradigm, 4 experiments were carried out in 3-day-old human newborns to assess the influence of translational displacement on perception of human locomotion. Experiment 1 shows that human newborns prefer a point-light walker display representing human locomotion as if on a treadmill over random motion. However, no preference for biological movement is observed in Experiment 2 when both biological and random motion displays are presented with translational displacement. Experiments 3 and 4 show that newborns exhibit preference for translated biological motion (Experiment 3) and random motion (Experiment 4) displays over the same configurations moving without translation. These findings reveal that human newborns have a preference for the translational component of movement independently of the presence of biological kinematics. The outcome suggests that translation constitutes the first step in development of visual preference for biological motion.