0000000000532522
AUTHOR
Nicolas Gueugneau
Motor cortical plasticity induced by motor learning through mental practice
Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP)-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1) excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after …
Central Contribution to Electrically Induced Fatigue depends on Stimulation Frequency
International audience; PURPOSE: This study analyzed the impact of several protocols of neuromuscular electrical stimulation (NMES), matched with a similar total torque-time integral, on muscle activation pathways and neuromuscular fatigue.METHODS: Ten young healthy participants (age: 24.6 +/- 4.2) performed 3 randomized NMES sessions on the triceps surae muscles with 20 Hz, 60 Hz or 100 Hz stimulation frequencies (pulse duration: 1 ms), with pulse amplitude (IES) set at 20 % of isometric maximal voluntary contraction (MVC). Muscle activity during NMES was assessed by means of the twitch, the soleus H-reflex and M wave responses evoked by single muscle stimulation at IES. Neuromuscular fati…
Daily modulation of the speed–accuracy trade-off
International audience; Goal-oriented arm movements are characterized by a balance between speed and accuracy. The relation between speed and accuracy has been formalized by Fitts’ law and predicts a linear increase in movement duration with task constraints. Up to now this relation has been investigated on a short-time scale only, that is during a single experimental session, although chronobiological studies report that the motor system is shaped by circadian rhythms. Here, we examine whether the speed–accuracy trade-off could vary during the day. Healthy adults carried out arm-pointing movements as accurately and fast as possible toward targets of different sizes at various hours of the …
Children with Dyslexia Have Altered Cross-Modal Processing Linked to Binocular Fusion. A Pilot Study
Patrick Quercia, 1 Thierry Pozzo, 2 Alfredo Marino, 3 Anne Laure Guillemant, 1 Céline Cappe, 4 Nicolas Gueugneau 1 1Université de Bourgogne, Dijon, Campus Universitaire, UFR STAPS, BP 27877, F-21078 Dijon, France; INSERM U1093, Cognition, Action et Plasticité Sensorimotrice, Dijon F-21078, France; 2Center for Translational Neurophysiology, Istituto Italiano di Tecnologia, Ferrara, Italy; 3Private Consultant, Vicenza 36100, Italie; 4Brain and Cognition Research Center, CerCo, CNRS UMR 5549, Toulouse, FranceCorrespondence: Patrick QuerciaMedical Office, 15 Rue du Clair Matin, Beaune 21200, FranceTel +33 6 87822741Email doc.quercia@gmail.comIntroduction: The ca…
<p>Children with Dyslexia Have Altered Cross-Modal Processing Linked to Binocular Fusion. A Pilot Study</p>
Introduction The cause of dyslexia, a reading disability characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities, is unknown. A considerable body of evidence shows that dyslexics have phonological disorders. Other studies support a theory of altered cross-modal processing with the existence of a pan-sensory temporal processing deficit associated with dyslexia. Learning to read ultimately relies on the formation of automatic multisensory representations of sounds and their written representation while eyes fix a word or move along a text. We therefore studied the effect of brief sounds on vision with a modification of binocular f…
<p>Alteration in binocular fusion modifies audiovisual integration in children</p>
Background: In the field of multisensory integration, vision is generally thought to dominate audiovisual interactions, at least in spatial tasks, but the role of binocular fusion in audiovisual integration has not yet been studied. Methods: Using the Maddox test, a classical ophthalmological test used to subjectively detect a latent unilateral eye deviation, we checked whether an alteration in binocular vision in young patients would be able to change audiovisual integration. The study was performed on a group of ten children (five males and five females aged 11.3±1.6 years) with normal binocular vision, and revealed a visual phenomenon consisting of stochastic disappearanceof part of a vi…
Modèles internes et imagerie motrice
L’imagerie motrice (IM) est la representation mentale d’une action, sans production concomitante de mouvement. Les techniques d’enregistrement et de stimulation du systeme nerveux central ont montre au cours de ces trois dernieres decennies que l’IM partageait des sites d’activation corticale et sous-corticale avec l’action reellement executee. Cette similitude, sans pour autant etre parfaitement identique, se retrouve aussi dans les activations peripheriques nerveuses et vegetatives. De plus, le travail mental est un element facilitateur de l’apprentissage, favorisant l’amelioration de la performance. Certains courants de pensee attribuent les mecanismes sous-jacents de l’IM et les benefic…
Interhemispheric inhibition is dynamically regulated during action observation
International audience; It is now well established that the motor system plays a pivotal role in action observation and that the neurophysiological processes underlying perception and action overlaps. However, while various experiments have shown a specific facilitation of the contralateral motor cortex during action observation, no information is available concerning the dynamics of interhemispheric interactions. The aim of the present study was, therefore, to assess interhemispheric inhibition during the observation of others' actions. We designed a transcranial magnetic stimulation (TMS) experiment in which we measured both corticospinal excitability and interhemispheric inhibition, this…
The influence of eye movements on the temporal features of executed and imagined arm movements.
The very close coordination between eye and hand indicates that eye movements are parts of the neural processes underlying the planning and control of arm movements. Eye movements are fundamental during observed actions and play a functional role in visual mental imagery. However, the role of eye movements during imagined actions is still unknown. Here, we report the timing features of eye and arm pointing movements for nine healthy participants in four conditions: Executed movements with orientation saccades (Eyes Free) or with no saccades (Eyes Motionless), and Imagined movements with Eyes Free or with Eyes Motionless. The first result was a facilitation effect of saccades upon both execu…
Stimulation magnétique transcrânienne et imagerie motrice : corrélats neurophysiologiques de l’action mentalement simulée
La stimulation magnetique transcrânienne (SMT) est devenue en a peine trois decennies un outil scientifique experimental majeur dans l’etude du systeme nerveux chez l’homme. Dotee de nombreux atouts methodologiques (technique non-invasive et a haute resolution temporelle), la SMT est complementaire des outils d’exploration fonctionnelle du cerveau et elle a permis d’accumuler un nombre considerable de donnees dans le domaine des neurosciences cognitives et comportementales. Cet article de synthese presente les recentes avancees en cognition motrice et plus particulierement en imagerie motrice, un champ de recherche dans lequel la SMT a ete grandement utilisee pour explorer l’implication des…
Interhemispheric inhibition during mental actions of different complexity.
International audience; Several investigations suggest that actual and mental actions trigger similar neural substrates. Yet, neurophysiological evidences on the nature of interhemispheric interactions during mental movements are still meagre. Here, we asked whether the content of mental images, investigated by task complexity, is finely represented in the inhibitory interactions between the two primary motor cortices (M1s). Subjects' left M1 was stimulated by means of transcranial magnetic stimulation (TMS) while they were performing actual or mental movements of increasing complexity with their right hand and exerting a maximum isometric force with their left thumb and index. Thus, we sim…
TIME-OF-DAY EFFECTS ON THE INTERNAL SIMULATION OF MOTOR ACTIONS: PSYCHOPHYSICAL EVIDENCE FROM POINTING MOVEMENTS WITH THE DOMINANT AND NON-DOMINANT ARM
It is well known that circadian rhythms modulate human physiology and behavior at various levels. However, chronobiological data concerning mental and sensorimotor states of motor actions are still lacking in the literature. In the present study, we examined the effects of time-of-day on two important aspects of the human motor behavior: prediction and laterality. Motor prediction was experimentally investigated by means of imagined movements and laterality by comparing the difference in temporal performance between right and left arm movements. Ten healthy participants had to actually perform or to imagine performing arm-pointing movements between two targets at different hours of the day …
Dominant vs. nondominant arm advantage in mentally simulated actions in right handers
Although plentiful data are available regarding mental states involving the dominant-right arm, the evidence for the nondominant-left arm is sparse. Here, we investigated whether right-handers can generate accurate predictions with either the right or the left arm. Fifteen adults carried out actual and mental arm movements in two directions with varying inertial resistance (inertial anisotropy phenomenon). We recorded actual and mental movement times and used the degree of their similarity as an indicator for the accuracy of motor imagery/prediction process. We found timing correspondences (isochrony) between actual and mental right arm movements in both rightward (low inertia resistance) …
Circadian Modulation of Mentally Simulated Motor Actions: Implications for the Potential Use of Motor Imagery in Rehabilitation
Background. Mental practice through motor imagery improves subsequent motor performance and thus mental training is considered to be a potential tool in neuromotor rehabilitation. Objective. The authors investigated whether a circadian fluctuation of the motor imagery process occurs, which could be relevant in scheduling mental training in rehabilitation programs. Methods. The executed and imagined durations of walking and writing movements were recorded every 3 hours from 8 AM to 11 PM in healthy participants. The authors made a cosinor analysis on the temporal features of these movements to detect circadian rhythms. Temporal differences between executed and imagined movements as well as …