Thesis (M.A.)--Miami University, Dept. of Psychology, 2009. / Title from first page of PDF document. Includes bibliographical references (p. 43-47).

Ce travail doctoral, centré sur l'étude des processus de contrôle d'un périphérique d'interaction de type joystick, poursuivait un double objectif. D'une part, ce travail visait à comprendre comment l'utilisateur d'un périphérique adapte son comportement pour faire face à l'ensemble des contraintes qu'il rencontre. En particulier, nous avons manipulé les contraintes relatives à la tâche à réaliser (l'indice de difficulté et le comportement de l'objet déplacé) et les propriétés physiques du périphérique. D'autre part, d'un point de vue appliqué, comprendre comment le comportement du sujet émerge d'un ensemble de contraintes nous renseigne sur la façon dont un contrôle plus intuitif des périphériques, et par la même une meilleure performance, peuvent être favorisés. Pour cela, un cadre d'analyse qui permet de manipuler l'ensemble des contraintes dans des conditions de contrôle qui se rapproche de situation réelle d'interaction (chirurgie vidéoassistée, aéronautique ou contrôle industriel) a été proposé. L'analyse comportementale à deux niveaux (niveau local et niveau global) qui est utilisée nécessitait l'intégration des concepts, moyens et méthodes des sciences comportementales (contrôle moteur) d'une part, et de la biomécanique d'autre part. Au regard des résultats obtenus, l'étude des processus de contrôle d'un périphérique d'interaction constitue une voie d'entrée sur une compréhension plus générale du comportement perceptivo-moteur. / This doctoral work focused on the study of the process involved in the control of a joystick-type device of interaction and had a double objective. First, this work was aimed to understand how the user of a device adapts its behavior to face a set of encountered constraints. In particular, the constraints inherent to the task (the index of difficulty and behavior of the object displaced) and the physical properties of the device (joystick or rotorcraft stick) have been manipulated. Second, understanding how the subject's behavior emerges from the influence of this set of constraints informed us about how we can access to a more intuitive control of the device and a better performance level. To achieve this goal, an analysis framework allowing the manipulation of all the constraints in conditions that are close to real situations of control (e.g. video-assisted surgery, aeronautics and industrial control) has been proposed. The behavioral analysis at two levels (local level and global level) that is used required the integration of concepts, means and methods from behavioral sciences (motor control) and from biomechanics. Taking all the results together, the study of the control process of a device of interaction allows a more general understanding of the perceptual-motor behavior.

L'espace entourant notre corps est d'une importance vitale: nous surveillons attentivement les objets (animés et inanimés) qui entrent dans les limites de l'espace à immédiate proximité du corps pour interagir avec eux. Dans le domaine des neurosciences cognitives, cet espace est exemplifié par le concept d'espace péripersonnel (PPS), une représentation hautement plastique qui intègre des stimuli tactiles et visuels présentés sur et près du corps. Cette représentation semble contribuer au guidage efficace des actions, cependant dans la littérature on ne retrouve aucune preuve substantielle de l'implication du PPS dans le contrôle des actions. Un argument en faveurs de cette hypothèse dériverait de la preuve que la plasticité du PPS peut effectivement survenir avant le début du mouvement, plutôt que pendant le mouvement. Les résultats de la première étude (chapitre II) révèlent que les informations visuelles et tactiles interagissent de manière significative déjà au cours de la phase de planification de l'action et que cette interaction visuo-tactile augmente ultérieurement au cours des étapes successives du mouvement. Un tel processus de « remappage » visuo-tactile du PPS, qui précède temporellement et accompagne par la suite l'exécution de l'action motrice, semble donc idéalement adapté à pour aider au guidage de nos actions. Récemment, il a été suggéré que le PPS pourrait jouer un rôle dans le guidage des interactions motrices entre individus. En psychologie sociale, l'espace autour du corps est appelé espace interpersonnel (IPS), défini comme l'espace que les individus maintiennent autour d'eux et dans lequel les autres ne peuvent pas pénétrer sans susciter d'inconfort. En raison de certaines similitudes entre les représentions du PPS et du IPS, certains auteurs ont soulevé la question d'un éventuel partage de certaines caractéristiques fonctionnelles entre ces deux représentations. Le deuxième objectif de ma thèse etait de tester cette hypothèse en exploitant un autre processus de «remappage» plastique du PPS, c'est-à-dire celui induit par l'utilisation d'un outil. Les résultats de la deuxième étude (chapitre IV) montrent que l'utilisation «standard» d'un outil «allonge» le PPS, mesuré par la distance d'atteignabilité d'une autre personne, mais n'influence pas l'IPS, mesuré par la distance de confort envers la même personne. Dans la troisième étude (chapitre V), nous avons introduit une nouvelle variante plus sociale de l'utilisation d'un outil pour examiner la plasticité sensorimotrice et sociale des deux espaces. Les résultats obtenus révèlent que l'utilisation sociale d'un outil «allonge» le PPS et en même temps «réduit» l'IPS. La démonstration que l'on peut induire des changements directionnellement opposés entre les deux représentations, falsifie l'hypothèse selon laquelle il peut y avoir un chevauchement fonctionnel entre PPS et IPS. Ces exemples de dissociation fonctionnelle peuvent donc servir à éviter une association inappropriée entre les deux concepts. Si l'hypothèse de l'identité fonctionnelle avec l'IPS ne semble pas légitime, il n'en demeure pas moins que le PPS est également sensible aux variables sociales. La dernière étude (Chapitre VII) vise donc à explorer cette sensibilité du PPS vers une dimension sociale fondamentale, encore inexplorée: la propriété privée. Les résultats de la quatrième étude indiquent que la propriété d'un objet, qu'elle soit considérée comme individuelle ou partagée, est essentielle pour l'émergence des propriétés dynamiques du PPS. Les stimuli visuels influencent effectivement la perception tactile d'une manière plus marquée au début du mouvement, mais seulement lorsque l'objet appartient au participant. Il convient de noter qu'un effet similaire apparaît également lorsque l'on observe une autre personne agir sur l'objet qui lui appartient... [etc] / The zone that surrounds our body is of vital importance: we carefully monitor the objects (both animate and inanimate) that enter the boundaries of the immediate space around the body to interact with them. In the neurocognitive field such a space is captured by the concept of peripersonal space (PPS), a highly plastic representation that integrates tactile and visual stimuli presented on, and close to, the body. This system seems to contribute to the efficient guidance of actions, yet, a clear demonstration of a prominent role of PPS in control of actions is critically lacking. Strong support for this would derive from evidence that PPS plastic changes occur before rather than after movement onset. The results from the first study (Chapter II) reveal that visual and tactile information strongly interact already during the planning phase of action and this visuo-tactile interaction is further enhanced during subsequent movement phases. Such a visuo tactile remapping of PPS that temporally precedes and subsequently accompanies overt motor execution is ideally suited to planning and guiding actions. Recently, it has been suggested a possible involvement of PPS in the guidance of motor interactions between individuals. In social psychology, the space around the body is termed interpersonal space (IPS), defined as the area individuals maintain around themselves into which others cannot intrude without arousing discomfort. Because of some similarities between the PPS and IPS constructs, some authors have raised the question of whether they share some functional features. The second aim of my thesis is to test this hypothesis by taking advantage of another PPS remapping, namely that one induces by tool-use. The results of the second study (Chapter IV) show that “standard” tool-use ‘extends’ PPS, as measured by reaching distance toward a peer, but does not affect IPS, as measured by the comfort distance toward the same peer. In the third investigation (Chapter V), we introduced a novel form of “social” tool-use setting to test for both sensorimotor and social plasticity of the two spaces. The findings that social tool–use ‘extends’ PPS and ‘reduces’ IPS, inducing opposite changes on each representation, clearly disconfirms the hypothesis . that there might be functional overlap between these sectors of space. Such examples of functional dissociation may therefore be sufficient to warn scholars to refrain from risky conflations between the two concepts. If the assumption of functional identity with IPS does not appear to be legitimate, it is true that PPS is sensitive to social features. The last study (Chapter VII) is thus aimed at probing this sensitivity of PPS to a so far unexplored but fundamental social dimension: ownership. The results from the forth study indicate that, whether considered to be as individual or shared property, ownership of an object is critical for the PPS dynamic properties to emerge. Visual stimuli affected touch perception more strongly at the movement onset than before, but only when the object belonged to the acting participant. Interestingly, a similar remapping was found when simply observing the peer acting on her own belonging. In a follow-up experiment we investigated PPS plastic changes when property of the target object was shared between the two agents. In this case, PPS remapping emerged not only when acting in first person, but also when observing the peer acting upon the shared object. Taken together, these findings critically inform current theoretical models about space around our body and about its function in our sensorimotor and social inter-actions

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Este trabalho apresenta a concepção, o projeto, o desenvolvimento e a validação experimental de uma plataforma robótica bioinspirada o robô KA\'I yxo com a habilidade de escalar árvores para aplicação em monitoramento ambiental. Tal motivação surgiu da necessidade crescente do estudo e do entendimento de ocorrências naturais pelas consequências envolvidas, muitas vezes trágicas. O monitoramento ambiental em larga escala e a dificuldade de acesso e cobertura de áreas significativas são fatores que indicam a importância e a utilidade de robôs nessas tarefas. O robô KA\'I yxo possui como aplicação primeira uma solução para aquisição de dados de radiação solar, temperatura, umidade e altitude, de maneira que a mesma seja uma ferramenta útil para pesquisadores, aplicação esta identificada como relevante para a pesquisa na área ambiental após visitas ao Instituto Nacional de Pesquisas da Amazônia INPA. O desenvolvimento da plataforma robótica bioinspirada exposto nesta tese apresenta a sua evolução, desde a versão inicial do robô Kamanbaré (seis versões), até a versão atual da plataforma KAI yxo (terceira versão). Para esta última, são expostos em detalhes os modelos mecânico e matemático. No modelo mecânico, a importante questão da mobilidade é considerada. O modelo matemático construído compreende a cinemática direta, a cinemática inversa, a definição da andadura e a dinâmica do robô. O texto contém também uma apresentação detalhada das arquiteturas de controle, de software e de hardware. A utilização de Geradores Centrais de Padrões (CPGs) é justificada e discutida em detalhes. O ajuste dos parâmetros da CPG é realizado por meio de um processo de otimização baseado na técnica de Times Assíncronos (A-Teams). Resultados experimentais obtidos com a plataforma robótica são apresentados e discutidos. / This work presents the conception, design, development and experimental validation of a bioinspired robotics platform the robot KA\'I yxo with the ability to climb trees for use in environmental monitoring. Such motivation arose from the growing need of studying and understanding the consequences of natural occurrences involved, often tragic. Environmental monitoring in large scale and the difficulty of access and coverage areas are significant factors that indicate the importance and the usefulness of robots in these tasks. As a first application, the robot KA\'I yxo represents a solution for data acquisition from solar radiation, temperature, humidity and altitude, so that it may be a useful tool for researchers. This application was identified as relevant to environmental research after visits to the National Institute of Amazonian Research INPA. The development of the bio-inspired robotics platform exposed in this thesis presents its evolution starting from the initial version of the robot Kamanbaré (six versions) and ending with the current version of KA\'I yxo platform (third version). For the latter, the mechanical and mathematical models are exposed in details. In the mechanical model, the important issue of mobility is considered. The mathematical model constructed comprises the forward kinematics, the inverse kinematics, the definition of the gait and the dynamics of the robot. The text also contains a detailed presentation of the control, software and hardware architectures. The use of Central Pattern Generators (CPGs) is justified and discussed. The tuning of the CPG parameters is performed by an optimization process based on the Asynchronous Teams (ATeams) technique. Experimental results obtained with the robotic platform are presented and discussed.

La conception des systèmes de contrôle embarqués devient de plus en plus complexe en raison des algorithmes utilisés, de l'augmentation des besoins industriels et de la nature des domaines d'applications. Une façon de gérer cette complexité est de concevoir les contrôleurs correspondant en se basant sur des plateformes numériques puissantes et ouvertes. Plus précisément, cette thèse s'intéresse à l'utilisation des plateformes FPGA System-on-Chip (SoC) pour la mise en œuvre des algorithmes d'entraînement électrique pour des applications avioniques. Ces dernières sont caractérisées par des difficultés techniques telles que leur environnement de travail (pression, température élevée) et les exigences de performance (le haut degré d'intégration, la flexibilité). Durant cette thèse, l'auteur a contribué à concevoir et à tester un contrôleur numérique pour un variateur de vitesse synchrone qui doit fonctionner à 200 °C de température ambiante. Il s'agit d'une commande par flux orienté (FOC) pour une Machine Synchrone à Aimants Permanents (MSAP) associée à un capteur de type résolveur. Une méthode de conception et de validation a été proposée et testée en utilisant une carte FPGA ProAsicPlus de la société Actel/Microsemi. L'impact de la température sur la fréquence de fonctionnement a également été analysé. Un état de l'art des technologies basées sur les SoC sur FPGA a été également présenté. Une description détaillée des plateformes numériques récentes et les contraintes en lien avec les applications embarquées a été également fourni. Ainsi, l'intérêt d'une approche basée sur SoC pour des applications d'entrainements électriques a été démontré. D'un autre coté et pour profiter pleinement des avantages offertes par les SoC, une méthodologie de Co-conception matériel-logiciel (hardware-software (HW-SW)) pour le contrôle d'entraînement électrique a été proposée. Cette méthode couvre l'ensemble des étapes de développement de l'application de contrôle à partir des spécifications jusqu'à la validation expérimentale. Une des principales étapes de cette méthode est le partitionnement HW-SW. Le but est de trouver une combinaison optimale entre les modules à mettre en œuvre dans la partie logiciel et celles qui doivent être mis en œuvre dans la partie matériel. Ce problème d'optimisation multi-objectif a été réalisé en utilisant l'algorithme de génétique, Non-Dominated Sorting Genetic Algorithm (NSGA-II). Ainsi, un Front de Pareto des solutions optimales peut être déduit. L'illustration de la méthodologie proposée a été effectuée en se basant sur l'exemple du régulateur de vitesse sans capteur utilisant le filtre de Kalman étendu (EKF). Le choix de cet exemple correspond à une tendance majeure dans le domaine des contrôleurs embraqués pour entrainements électriques. Par ailleurs, la gestion de l'architecture du contrôleur embarqué basée sur une approche SoC a été effectuée en utilisant un système d'exploitation temps réel. Afin d'accélérer les services de ce système d'exploitation, une unité temps réel a été développée en VHDL et associée au système d'exploitation. Il s'agit de placer les services d'ordonnanceur et des processus de communication du système d'exploitation logiciel au matériel. Ceci a permis une accélération significative du traitement. La validation expérimentale d'un contrôleur du courant a été effectuée en utilisant un banc de test du laboratoire. Les résultats obtenus prouvent l'intérêt de l'approche proposée. / Designing embedded control systems becomes increasingly complex due to the growing of algorithm complexity, the rising of industrials requirements and the nature of application domains. One way to handle with this complexity is to design the corresponding controllers on performing powerful and open digital platforms. More specifically, this PhD deals with the use of FPGA System-on-Chip (SoC) platforms for the implementation of complex AC drive controllers for avionic applications. These latters are characterized by stringent technical issues such as environment conditions (pressure, high temperature) and high performance requirements (high integration, flexibility and efficiency). During this thesis, the author has contributed to design and to test a digital controller for a high temperature synchronous drive that must operate at 200°C ambient. It consists on the Flux Oriented Controller (FOC) for a Permanent Magnet Synchronous Machine (PMSM) associated with a Resolver sensor. A design and validation method has been proposed and tested using a FPGA ProAsicPlus board from Actel-Microsemi Company. The impact of the temperature on the operating frequency has been also analyzed. A state of the art FPGA SoC technology has been also presented. A detailed description of the recent digital platforms and constraints in link with embedded applications was investigated. Thus, the interest of a SoC-based approach for AC drives applications was also established. Additionally and to have full advantages of a SoC based approach, an appropriate HW-SW Co-design methodology for electrical AC drive has been proposed. This method covers the whole development steps of the control application from the specifications to the final experimental validation. One of the main important steps of this method is the HW-SW partitioning. The goal is to find an optimal combination between modules to be implemented in software and those to be implemented in hardware. This multi-objective optimization problem was performed with the Non-Dominated Sorting Genetic Algorithm (NSGA-II). Thus, the Pareto-Front of optimal solution can be deduced. The illustration of the proposed Co-design methodology was made based on the sensorless speed controller using the Extended Kalman Filter (EKF). The choice of this benchmark corresponds to a major trend in embedded control of AC drives. Besides, the management of SoC-based architecture of the embedded controller was allowed using an efficient Real-Time Operating System (RTOS). To accelerate the services of this operating system, a Real-Time Unit (RTU) was developed in VHDL and associated to the RTOS. It consists in hardware operating system that moves the scheduling and communication process from software RTOS to hardware. Thus, a significant acceleration has been achieved. The experimentation tests based on digital current controller were also carried out using a laboratory set-up. The obtained results prove the interest of the proposed approach.

The striatum represents the main input nucleus of the basal ganglia, a system of subcortical nuclei critically involved into motor control and motivational processes and altered in several conditions such as Parkinson’s diseases or drug addiction. The projection neurons of the striatum are GABAergic (γ-aminobutyric acid) medium-sized spiny neurons (MSNs), and account for the large majority of striatal neurons, while interneurons represent about 10% of striatal cells. The MSNs are subdivided into two subpopulations that form two main efferent pathways: the striatonigral and striatopallidal neurons. The striatonigral MSNs project to the entopeduncular nucleus (EP) and substancia nigra pars reticulata (SNr) (direct pathway) and co-express dopamine D1 receptors (D1R) and substance P neuropeptide (SP). On the other hand, striatopallidal MSNs project to the lateral globus pallidus (LGP) (indirect pathway) and co-express dopamine D2 receptor (D2R), adenosine A2A receptor (A2AR) and enkephalin (Enk). The D1R striatonigral and D2R striatopallidal MSNs are equal in number and shape and are mosaically distributed through all the striatum. The dorsal striatum is mainly involved in motor control and learning while the ventral striatum is crucial for motivational processes. In view of the still debating respective functions of projection D2R-striatopallidal and D1R-striatonigral neurons and striatal interneurons, both in motor control and learning of skills and habits but also in more cognitive processes such as motivation, we were interested in the development of models allowing the removal of selective striatum neuronal populations in adult animal brain. Because of the mosaical organisation of the striatum, a targeting of specific neuronal type, with techniques such as chemical lesions or surgery, is still impossible. Taking advantage of new transgenic approaches, the goal of the present work was to generate and/or to initiate the characterization of genetic models in which a selective subtype of striatal neuron can be ablated in an inducible way. We used a transgenic approach in which mice express a monkey diphtheria toxin (DT) receptor (DTR) in D2R-striatopallidal or D1R-striatonigral neurons. Local stereotactic injections of DT can then induce selective neuronal ablation in functionally different striatal areas.<p>We first investigated functions of D2R-striatopallidal neurons in motor control and drug reinforcement by their selective ablation in the entire striatum or restricted to the ventral striatum. This DTR strategy produced selective D2R striatopallidal MSN ablation with integrity of the other striatal neurons as well as the striatal dopaminergic function. D2R MSN ablation in the entire striatum induced permanent hyperlocomotion while ventral striatum-restricted ablation increased amphetamine place preference.<p>We next compared respective roles of D2R-striatopallidal and D1R-striatonigral neurons in motor control and skill learning in functionally different striatum subregions.<p>Finally, to target nitrergic interneurons of the striatum, we developed a bacterial artificial chromosome genetic strain in which the cre-recombinase expression is under the control of the neuronal nitric oxide gene promoter.<p><p>Altogether, those results show that DTR expression and DT local injections is an efficient and flexible strategy to ablate selective striatum neuronal types with spatial resolution. We provide the first direct experimental evidences that D2R striatopallidal neurons inhibit both locomotor and drug-reinforcement processes and that D2R and D1R MSNs in different striatum subregions have distinct functions in motor control and motor skill learning. Those results strongly support a cell-type and topographic functional organization of the striatum and underscore the need for characterization of the specific cellular and molecular modifications that are induced in D2R and D1R MSNs during drug-reinforcement or procedural learning.<p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Le récepteur aux cannabinoïdes de type 1 (CB1) est un récepteur couplé aux protéines G, abondamment exprimé dans le cerveau et régulant plusieurs processus physiologiques. Cependant, les mécanismes cellulaires par lesquels les CB1 régulent ces processus n’ont été que peu analysés. Bien que les CB1 localisés dans les membranes plasmiques sont connus pour induire la transduction de signal; une partie de ces récepteurs sont aussi fonctionnels au niveau des mitochondries (mtCB1), où leur stimulation réduit la respiration mitochondriale. L’objectif de cette thèse fut d’évaluer l’impact de l’activation des récepteurs mtCB1 du cerveau sur les effets connus des cannabinoïdes. Afin de distinguer la fonction des mtCB1 de celle des autres populations de récepteurs, nous avons développé des outils basés sur la signalisation induite par les mtCB1. Dans les mitochondries isolées de cerveau, l’activation des protéines Gαi/o, dépendante des mtCB1 diminue l’activité de l’adénylyl cyclase soluble (sAC). L'inhibition locale de l’activité de sAC prévient l’amnésie, la catalepsie et partiellement l’hypolocomotion induite par les cannabinoïdes. De plus, nous avons généré une protéine fonctionnelle mutante CB1 (DN22-CB1) dépourvue des 22 premiers acides aminés des CB1 ainsi que de sa localisation mitochondriale. Contrairement aux CB1, l'activation des DN22-CB1 n’affecte pas l'activité mitochondriale. Enfin, l’expression des DN22-CB1 dans l’hippocampe bloque à la fois la diminution de la transmission synaptique et l’amnésie induites par les cannabinoïdes. Ces travaux démontrent l’implication des mtCB1 dans certains effets des cannabinoïdes et le rôle clé des processus bioénergétiques contrôlant les fonctions cérébrales. / Type-1 cannabinoid receptor CB1 is a G protein-coupled receptor (GPCR), widely expressed in the brain, which regulates numerous physiological processes. However, the cellular mechanisms of CB1-mediated control of these functions are poorly understood. Although CB1 are known to signal at the plasma membrane, a portion of these receptors are also present in mitochondria (mtCB1), where mtCB1 activation decreases mitochondrial activity. The goal of this thesis was to dissect the impact of brain mtCB1 signaling in known behavioral effects induced by cannabinoids. To distinguish the functions of mtCB1 from other receptor pools, we developed tools based on the characterization of the intra-mitochondrial molecular cascade induced by mtCB1 receptors. In isolated brain mitochondria, we found that intra-mitochondrial decrease of soluble-adenylyl cyclase (sAC) activity links mtCB1- dependent activation of Gαi/o proteins to decrease cellular respiration. Local brain inhibition of sAC activity blocks cannabinoid-induced amnesia, catalepsy and contributes to the hypolocomotor effect of cannabinoids. In addition, we generated a functional mutant CB1 protein (DN22-CB1) lacking the first 22 amino acid of CB1 and its mitochondrial localization. Differently from CB1, activation of DN22-CB1 does not affect mitochondrial activity. Hippocampal in vivo expression of DN22-CB1 abolished both cannabinoid-induced impairment of synaptic transmission and amnesia in mice. Together, these studies couple mitochondrial activity to behavioral performances. The involvement of mtCB1 in the effects of cannabinoids on memory and motor control highlights the key role of bioenergetic processes as regulators of brain functions.

Neste estudo foi analisado o efeito de distância, velocidade, tamanhos do disco e do alvo, e massas do disco e da manopla, sobre o desempenho motor em movimentos requisitando rapidez e precisão. Para tanto, foram analisadas as características cinemáticas da tarefa de projetar um disco a um alvo com movimento de contato balístico, empunhando uma manopla. Os movimentos foram desempenhados sobre uma base plana e filmados com câmera optoeletrônica de alta freqüência. O estudo foi conduzido em seis experimentos com um grupo único de participantes. Os resultados indicaram que os modelos de controle motor que têm sido empregados para analisar a relação velocidade-precisão em tarefas mais simples não foram apropriados para explicar o comportamento da tarefa utilizada. O controle motor na tarefa demonstrou ser dinâmico e flexível, frente às diferentes restrições de movimento. As seguintes estratégias de controle foram sugeridas na explicação dos resultados: sincronização da maior velocidade e do instante de contato manopla-disco, manutenção na proporção entre as fases aceleração-desaceleração, maior inércia e menor impacto para aumentar a estabilidade de movimento, e o controle da velocidade e da precisão em dimensões independentes. A análise das ações articulares demonstrou as particularidades das estratégias utilizadas pelo sistema no movimento em função das variáveis manipuladas. Em conjunto, esta seqüência de experimentos permitiu uma compreensão mais ampla das estratégias de controle motor empregadas em movimentos com alta demanda de velocidade e de precisão / In this study it was analyzed the effect of distance, velocity, disc and target width, disc and manipulandum mass, over motor control of a rapid and accurate movement. For such, it was analyzed the kinematic characteristics of the task of launching a disc to a target using a ballistic movement, performed with a manipulandum. Movements were performed on a flat surface and filmed with a high frequency optoelectronic camera. The study was conducted through six experiments with a single group of participants. Analysis of results indicated that models of motor control that has been used to analyze speed-accuracy tradeoff in simpler tasks were not appropriate to explain the observed behavior in the task used. Motor control in the task showed to be dynamic and flexible, regarding the several constraints manipulated. The follow strategies of control were suggested to explain the results: synchronization of the peak velocity and the instant of disc-manipulandum contact, maintenance of the proportion between the acceleration-deceleration phases, greater inertia and minor impact to increase movement stability, and control of velocity and accuracy of independent dimensions. The prediction of Analysis of joint actions showed the particularities of the strategies used by the system on movement as a function of the manipulated variables. Together, this study sequence of experiments allowed for a deeper comprehension of the control strategies used in the control of rapid and accurate movements

No description available.