The topic of this work is motor imagery. Through 7 different studies, the process and proprieties of motor imagery and its impact on motor learning were assessed. It was found that this cognitive activity is closely linked to the motor system. This characteristic underlies the positive effects of motor imagery on motor learning. This can have many practical applications in the domain of sport and motor rehabilitation.<p><p> / Doctorat en Sciences Psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

M.A. / The aim of the study was to investigate whether evoked potential distinguishes between motor coordinated and-uncoordinated African children. Because the brain functions as a unified entity and different brain systems are integrated simultaneously, it was postulated that there is a relationship between the auditory evoked potential of the brain stem on the one hand and motor coordination on the other hand, that is, the sensory and the motor systems are related. Sensory- motor activity is thus perceived to form a unified function within the total framework of human functioning. The relevant literature points to a possible relationship between the auditory evoked potential of the brain stem and motor coordination. Patients with degenerative diseases such as Parkinson's disease and multiple sclerosis exhibit abnormal evoked potential responses as well as unusual motor behaviour and coordination. Similarly, children with hearing problems also show unusual evoked potential responses of the brain stem as well as motor lethargy(delayed motor responses) and clumsiness. As a result of these tendencies it was postulated that evoked potential would be able to distinguish between motor-coordinated and -uncoordinated subjects. The brain's evoked potential response is a robust phenomenon that provides a record of electrical brain activity, even in trials where overt responses are not usually expected. The present study focuses on the auditory evoked potential of the brain stem (AEP). The evoked potential serves as a measure of the sensory transmission of information in the brain and consequently highlights the neural activity underlying normal sensory experiences. The subjects selected for the study were 46 eight- to twelve-year-old African children attending a farm school. They can be regarded as representative of the population of eight- to twelve-year old African farm children. All the subjects were administered the Quick Neurological Screening Test in order to catagorise them into two groups, namely the motor-coordinated group and the motor-uncoordinated group. Thereafter the auditory evoked potential of the brain stem was recorded from all the subjects in both groups ...

Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder. Because motor signs are the defining feature of GTS, addressing the neurophysiology of motor processes is central to understanding GTS. The integration of voluntary motor processes is subject to so-called “binding problems”, i.e., how different aspects of an action are integrated. This was conceptualized in the theory of event coding, in which ‘action files’ accomplish the integration of motor features. We examined the functional neuroanatomical architecture of EEG theta band activity related to action file processing in GTS patients and healthy controls. Whereas, in keeping with previous data, behavioral performance during action file processing did not differ between GTS and controls, underlying patterns of neural activity were profoundly different. Superior parietal regions (BA7) were predominantly engaged in healthy controls, but superior frontal regions (BA9, BA10) in GTS indicated that the processing of different motor feature codes was central for action file processing in healthy controls, whereas episodic processing was more relevant in GTS. The data suggests a cascade of cognitive branching in fronto-polar areas followed by episodic processing in superior frontal regions in GTS. Patients with GTS accomplish the integration of motor plans via qualitatively different neurophysiological processes.

Ce travail de thèse visait à étudier les effets de l'immobilisation de courte durée d'un membre sur les processus cognitifs impliqués dans la planification et le contrôle des mouvements. Précisément, nous avons examiné l'impact d'une immobilisation de courte durée du membre supérieur (main droite ou gauche) sur la représentation mentale des actions de ce membre. Pour cela, nous avons eu recours à une tâche d'imagerie motrice implicite (rotation mentale de stimuli corporels), en partant du principe qu'un ensemble de processus cognitifs similaires sont sollicités que l'action soit réellement ou simplement simulée. Nos résultats indiquent que l'inactivité physique modifie le fonctionnement des processus cognitifs permettant la réalisation et l'optimisation des actions. L'immobilisation de courte durée du membre supérieur altère la capacité des sujets à se représenter mentalement des actions. L'effet de ces perturbations (changement de stratégie d'imagerie, transfert inter-membre…) peut varier d'un individu à l'autre, ainsi qu'en fonction des contraintes de la tâche d'imagerie implicite et de la durée de l'immobilisation. Un second objectif visait à examiner le potentiel de l'imagerie motrice explicite pour réactiver le système sensorimoteur suite à la période d'immobilisation de la main. Nous montrons qu'une pratique mentale en imagerie motrice kinesthésique pendant la période d'immobilisation permet de contrecarrer les perturbations fonctionnelles induite par la restriction d'exercice. / The present thesis focused on the effects of short-term limb immobilization on the cognitive level of action control. Especially, we examined the influence of short-term upper-limb immobilization (right or left-hand) on the mental representation of action. To this aim, an implicit motor imagery task (mental rotation of body-stimuli) was used, assuming similar processes between motor simulation and motor execution. Results showed that physical inactivity affects the cognitive processing of action. Short-term upper-limb immobilization impaired the ability to mentally represent action. The immobilization-induced effects (switch from a motor to a visual imagery strategy, inte-limb transfer…) may vary from one individual to another, and may depend on the constraints of the implicit imagery task or with the period of immobilization (24h vs. 48h). A second aim of this thesis was to examine the potential of explicit motor imagery to reactivate the sensorimotor system after the period of sensorimotor restriction. We showed that kinesthetic imagery practice during the period of immobilization can counteract the functional impairment induced by sensorimotor restriction.

An efficient integration of sensory and motor processes is crucial to goal-directed behavior. Despite this high relevance, and although cognitive theories provide clear conceptual frameworks, the neurobiological basis of these processes remains insufficiently understood. In a double-blind, randomized placebo-controlled pharmacological study, we examine the relevance of catecholamines for perception-motor integration processes. Using EEG data, we perform an in-depth analysis of the underlying neurophysiological mechanisms, focusing on sensorimotor integration processes during response inhibition. We show that the catecholaminergic system affects sensorimotor integration during response inhibition by modulating the stability of the representational content. Importantly, catecholamine levels do not affect the stability of all aspects of information processing during sensorimotor integration, but rather—as suggested by cognitive theory—of specific codes in the neurophysiological signal. Particularly fronto-parietal cortical regions are associated with the identified mechanisms. The study shows how cognitive science theory-driven pharmacology can shed light on the neurobiological basis of perception-motor integration and how catecholamines affect specific information codes relevant to cognitive control.

Le syndrome de Gilles de la Tourette (SGT) est une condition neuropsychiatrique qui se caractérise par la présence de tics moteurs et vocaux. Au-delà des tics, le SGT s’accompagne souvent de troubles concomitants, tels que le trouble de déficit de l’attention avec ou sans hyperactivité et le trouble obsessionnel compulsif. Plusieurs études ont rapporté que les adultes atteints du SGT sont plus susceptibles de souffrir de dépression et de troubles anxieux comorbides que les personnes neurotypiques. Bien que les tics soient la caractéristique déterminante du SGT, les comorbidités engendrent de multiples conséquences psychologiques, sociales et comportementales, en plus d’avoir un impact considérable sur la qualité de vie des personnes qui en souffre. Jusqu'à présent, les études neuropsychologiques auprès de cette population ont révélé des résultats parfois conflictuels quant à leurs performances cognitives, notamment au niveau de l’inhibition, des processus moteurs et des capacités visuospatiales. Ces disparités peuvent être attribuées à divers facteurs, y compris la présence de comorbidités. L’objectif général de ce mémoire est d’apporter une meilleure compréhension du profil neuropsychologique des individus atteints du SGT, en tenant compte de la comorbidité anxiodépressive. Notre échantillon est composé de 128 participants divisés en trois groupes : un groupe SGT+ présentant une comorbidité anxieuse et/ou dépressive (n = 21), un groupe clinique SGT- sans comorbidité significative (n = 37) et un groupe contrôle neurotypique (n = 70). Ils ont été soumis à des mesures neuropsychologiques, dont le Stroop Color-Word Test (SCWT), le Purdue Pegboard Test (PPT) et la figure complexe de Rey-Osterrieth (ROCF). Concernant les capacités d’inhibition, aucune différence n'a été observée entre les groupes cliniques et les neurotypiques. Les patients SGT- et SGT+ ont tous deux montré une dextérité motrice supérieure. Toutefois, seuls les participants atteints de SGT+ ont présenté des déficits au niveau des fonctions visuoconstructives et de la mémoire non verbale. Les résultats suggèrent que les individus atteints du SGT avec une comorbidité anxiodépressive pourraient présenter des déficits supplémentaires dans certains domaines spécifiques. Néanmoins, des recherches supplémentaires axées sur ces conditions comorbides sont nécessaires pour tirer des conclusions robustes. / Tourette's syndrome (TS) is a neuropsychiatric condition characterized by the presence of motor and vocal tics. Beyond tics, TS is often accompanied by co-occurring disorders, such as attention deficit disorder with or without hyperactivity and obsessive-compulsive disorder. Several studies have reported that adults with TS are more likely to suffer from depression and comorbid anxiety disorders than neurotypical people. Although tics are the defining characteristic of TS, comorbidities have multiple psychological, social, and behavioural consequences, and they considerably impact the quality of life of those who suffer from them. So far, neuropsychological studies in this population have revealed sometimes conflicting results regarding their cognitive performance, particularly in inhibition, motor processes and visuospatial abilities. These disparities can be attributed to a variety of factors, including the presence of comorbidities. The general objective of this thesis is to provide a better understanding of the neuropsychological profile of individuals with TS, considering anxiodepressive comorbidity. Our sample consisted of 128 participants divided into three groups: a TS+ group with an anxiety and/or depressive comorbidity (n = 21), a clinical group TS- without significant comorbidity (n = 37) and a neurotypical control group (n = 70). They were subjected to neuropsychological measures, including the Stroop Color- Word Test (SCWT), the Purdue Pegboard Test (PPT), and the Rey-Osterrieth Complex Figure (ROCF). Regarding inhibition abilities, no differences were observed between clinical and neurotypical groups. Both TS- and TS+ patients showed superior motor dexterity. However, only participants with TS+ had deficits in visuoconstructive function and nonverbal memory. The results suggest that individuals with TS with an anxiodepressive comorbidity may have additional deficits in some specific areas. Nevertheless, further research focused on these comorbid conditions is needed to draw robust conclusions.