No description available.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Visuomotor adaptation arises when reaching in an altered visual environment, where one’s seen hand position does not match their felt (i.e., proprioceptive) hand position in space. Here, we investigated if proprioceptive training (PT) benefits visuomotor adaptation, and if these benefits arise due to implicit (unconscious) or explicit (conscious strategy) processes. A total of 72 participants were divided equally into 3 groups: Proprioceptive training with feedback (PTWF), Proprioceptive training no feedback (PTNF), and Control (CTRL). The PTWF and PTNF groups completed proprioceptive training (PT), where a participant’s hand was passively moved to an unknown reference location and they judged the felt position of their unseen hand relative to their body midline on every trial. The PTWF group received verbal feedback with respect to their response accuracy on the middle 60% of trials. The CTRL group did not complete PT and instead sat quietly during this time. Following PT or time delay, all three groups reached when seeing a cursor that was rotated 30° clockwise relative to their hand motion, followed by a series of no-cursor reaches to assess implicit and explicit adaptation. Results indicated that the PTWF group improved their sense of felt hand position following PT. However, this improved proprioceptive acuity did not benefit visuomotor adaptation, as all three groups showed similar visuomotor adaptation across rotated reach training trials. Visuomotor adaptation arose implicitly, with minimal explicit contribution for all three groups. Thus, these results suggest that passive proprioceptive training with feedback does not benefit, nor hinder, implicit visuomotor adaptation.

La proprioception est la modalité essentielle pour la construction du schéma corporel (SC) qui se construit au cours de la vie. Cette thèse cherche à comprendre la construction du SC au cours du développement en explorant l’intégration proprioceptive (IP). L’utilisation des vibrations tendineuses en IRMf chez l’enfant et l’adulte, révèle que les bases neurales de l’IP sont établies dès 7 ans. Mais, chez l’enfant apparait une moindre activation des régions pariétales et sensorielles ainsi que l’activation du cortex frontopolaire, confirmant la lente maturation de l’IP. L’étude de la maturation de l’acuité proprioceptive (AP) corrélé à des données d’IRMf de repos chez l’enfant et l’adulte révèle que l’AP est supportée dès 8 ans par une interaction entre le réseau sensorimoteur (SMN) et frontopariétal (FPN). Chez l’enfant seulement apparait une relation inverse entre FPN-SMN et AP et une relation cerebello-corticales et AP. Un désengagement des connexions cerebello-corticales laisse place à des connexions cortico-corticales avec l’âge. L’exploration du couplage perception-action, essentiel pour la construction du SC, révèle que la manipulation de l’action impacte plus largement la perception des enfants et des adolescents. La construction d’une représentation stable grâce à ce couplage est fonctionnelle dès 6 ans mais poursuit sa maturation au cours de l’adolescence. Nous avons révélé l’établissement précoce et la lente maturation des bases neurales du SC. L’engagement de structures supplémentaires chez l’enfant renforcerait le neurodéveloppement du SC. La construction du SC utilisant l’IP est moins efficace chez les enfants et les adolescents révélant sa lente maturation. / Proprioception is the sensory modality essential to body schema (BS) building which is built through ontogenesis. This thesis’ aim highlights the building of the BS through childhood and adolescence by exploring proprioceptive integration (PI) at both behavioural and brain level. Using tendon vibration during fMRI in children and adults, revealed that the neural basis of BS are already established from the age of 7. Yet, in children appeared a less activation of parietal and sensory areas as well as an exclusive activation of the frontopolar cortex confirming the slow maturation of PI. Proprioceptive acuity (PA) assessment correlated with resting state data in children and adults revealed that PA is supported by an interaction between the sensorimotor and the frontoparietal networks in both groups. Yet, in children only, this interaction is reversed compared to adults, and they presented also the involvement of cortico-cerebellar connexions to support PA. The disengagement of cortico-cerebellar connexions leaves room to cortico-cortical connexions with age. The evaluation of the perception-action coupling, essential to the BS building through development, revealed that action strongly impact children’s and adolescents’ perception of human body. The building of a reliable representation thanks to this coupling, is present from the age of 6 but continue its maturation through adolescence. Therefore, we revealed the early establishment and the slow maturation of the BS neural basis. The engagement of additional structures in children would reinforce the BS neurodevelopment. The BS building using PI is less efficient in children and adolescents revealing its slow maturation.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

In this thesis, we develop a method using fuzzy logic to do cooperative localization. In a group of robots, at a given instant, each robot gives crisp pose estimates for all the other robots. These crisp pose values are converted to fuzzy membership functions based on various physical factors like acceleration of the robot and distance of separation of the two robots. For a given robot, all these fuzzy estimates are taken and fused together using fuzzy fusion techniques to calculate a possibility distribution function of the pose values. Finally, these possibility distributions are defuzzified using fuzzy techniques to find a crisp pose value for each robot. A MATLAB code is written to simulate this fuzzy logic algorithm. A Kalman filter approach is also implemented and then the results are compared qualitatively and quantitatively.

In this thesis, we develop a method using fuzzy logic to do cooperative localization. In a group of robots, at a given instant, each robot gives crisp pose estimates for all the other robots. These crisp pose values are converted to fuzzy membership functions based on various physical factors like acceleration of the robot and distance of separation of the two robots. For a given robot, all these fuzzy estimates are taken and fused together using fuzzy fusion techniques to calculate a possibility distribution function of the pose values. Finally, these possibility distributions are defuzzified using fuzzy techniques to find a crisp pose value for each robot. A MATLAB code is written to simulate this fuzzy logic algorithm. A Kalman filter approach is also implemented and then the results are compared qualitatively and quantitatively.

When subjects are presented with distorted visual feedback of their hand during a goal-directed movement (i.e. subjects view a cursor representing their hand that is rotated from their hand’s actual position while reaching in a virtual reality environment), they typically adapt their movements so that the cursor is brought to the target, thus reducing reaching errors. In addition to motor adaptation, it has recently been shown that reaching with distorted visual feedback of the hand results in sensory changes, such that proprioceptive estimates of hand position are shifted in the direction of the visual feedback (Cressman and Henriques 2009). The current study looked to establish how quickly these sensory changes arise while training to reach with distorted visual feedback of the hand. Additionally, by comparing sensory to motor changes across time, we looked to determine the relationship between their underlying processes. Subjects trained to reach to a single visual target while seeing a cursor that was aligned with their actual hand position (50 trials: aligned reach training), or rotated 30° clockwise (CW) relative to their actual hand position (150 trials: rotated reach training). Reach errors and proprioceptive estimates of felt hand position were assessed following the aligned reach training trials and at 7 different times during the rotated reach training trials by having subjects reach to the target without visual feedback, and provide estimates of the position of their hand relative to a visual reference marker respectively. Results revealed a slow change in proprioceptive estimates over the course of reach training with the rotated cursor relative to estimates after the aligned reach training, and in fact, significant sensory changes were not observed until after 70 trials. In contrast, reach adaptation showed a much steeper increase and significant adaptation after a limited number of reach training trials with a rotated cursor. These different time courses suggest that proprioceptive recalibration and reach adaptation arise due to separate neural processes.

Proprioception is recalibrated following reaches with misaligned visual feedback of the hand, such that one’s sense of felt hand position is shifted in the direction of the visual feedback provided (Cressman & Henriques 2009). In the current experiment, we examined the ability of proprioceptive recalibration to be retained over an extended period of time (i.e. 4 days), and the benefits of additional training on retention in the form of recall and savings (i.e. faster re-learning on subsequent testing days). Twenty-four participants trained to reach to a target while seeing a cursor that was rotated 30° clockwise relative to their hand on an initial day of testing. Half of the participants then completed additional reach training trials on 4 subsequent testing days (Training group), whereas the second half of participants did not complete additional training (Non-Training group). Participants provided estimates of their felt hand position on all 5 testing days to establish retention of proprioceptive recalibration. Results revealed that proprioceptive recalibration was recalled 24 hours after initial training and that there was no benefit of additional training. Retention in the form of savings was observed on all days for the Training group and on Day 5 in the Non-Training group. These results reveal that proprioceptive recalibration does not benefit from additional training but is retained in the form of recall and savings. Taken together, results from the two groups of participants showed that the sensory system’s ability to change over time appeared to saturate early on, within two days of training. Moreover, the different time scales (i.e. 1 day for recall versus 4 days for savings), suggested that distinct processes may underlie recall and savings of proprioceptive recalibration.

Bakgrund: Frusen skuldra (FS) är ett smärttillstånd som drabbar 2-5% av befolkningen och som påverkar skulderfunktionen. I dagsläget finns det ingen konsensus kring den bästa behandlingsformen vid FS, dock anses proprioceptiv neuromuskulär facilitering (PNF) ge minskad smärta och ökad rörlighet (ROM) samt skulderfunktion.   Syfte: Att kartlägga evidensen av PNF som behandling vid FS. Det var även att granska kvaliteten i inkluderade studier och att studera effekten av PNF på skulderfunktion och ROM. Metod: En systematisk litteraturstudie. Sökningen utfördes i databaserna PubMed, Cochrane, Web of Science samt Google scholar. Artiklarna kvalitetsgranskades med PEDro scale och tillförlitligheten graderades med GRADEstud.  Resultatsammanfattning: Åtta artiklar inkluderades i studien med totalt 360 deltagare. Enligt PEDro scale varierade kvaliteten i studierna mellan tre till åtta poäng. Evidensgraderingen enligt GRADEstud visade mycket låg (+) evidens gällande skulderfunktion och låg (++) evidens gällande ROM. Graderingen baserades på fyra studier av hög kvalitet vid skulderfunktion respektive ROM. Studiernas resultat var motstridiga gällande huruvida PNF ger en signifikant positiv effekt på skulderfunktion och ROM vid FS. Konklusion: Det finns mycket låg (+) evidens för att PNF skulle ha en effekt på skulderfunktionen och en låg (++) evidens för att PNF har en effekt på ROM. För att förtydliga evidensen och användningen av PNF behövs fler studier av hög kvalitet och med liknande tillvägagångssätt. / Background: Frozen shoulder (FS) is a painful condition affecting 2-5% of the population and it affects the shoulder function. Currently there’s no consensus to which treatment is most effective in FS. However, proprioceptive neuromuscular facilitation (PNF) is assumed to bring pain relief and increase range of motion (ROM) and shoulder function.  Objective: To review the evidence regarding the effect of PNF as treatment in patients with FS. It’s also to examine the quality of included studies and to study the effect of PNF on shoulder function and ROM.  Method: A systematic review. The search was conducted in the databases of PubMed, Cochrane, Web of Science and Google scholar. The quality was assessed according to PEDro scale and the reliability with GRADEstud.  Results: Eight studies were included with a total of 360 participants. The quality of the studies ranged between three to eight points according to PEDro scale. According to GRADEstud PNF received very low (+) evidence for shoulder function and low (++) evidence for ROM. The grading was based on four, high quality studies for both shoulder function and ROM. The included studies were conflicting regarding whether PNF had a significant, positive effect on shoulder function and ROM in FS.   Conclusion: There’s very low (+) evidence that PNF would have an effect on shoulder function and low (++) evidence that PNF has an effect on ROM. In order to clarify the evidence there’s a need for future well-conducted studies with a similar approach.