No description available.

No description available.

No description available.

La stimulation cérébrale profonde (SCP) est une procédure chirurgicale utilisée dans le traitement de divers contextes pathologiques. Ce système, composé d’électrodes implantées dans une région cible du cerveau et d’un neurostimulateur reliés par un fil, permet de délivrer un courant électrique dans une région voulue du cerveau. À ce jour, les mécanismes d’action de la SCP et les effets cellulaires qu’elle engendre demeurent mal connus. Cette problématique découle du fait qu’il existe peu de prototypes de micro-stimulation dans le domaine de la recherche, sans compter que ceux-ci ne répondent pas bien aux critères de cette recherche. Mes travaux de maîtrise visaient donc à développer un système de microstimulation pouvant être utilisé chez la souris et de développer et valider toutes les techniques nécessaires à l’implantation de ce système chez la souris. Au terme de ces travaux, nous avons développé un système de micro-stimulation : 1) utilisable chez la souris 2) pour des protocoles de stimulation chronique de longue durée (jusqu’à 1 mois), 3) possédant des paramètres électriques, semblables à ceux utilisés chez l’humain en clinique, 4) pouvant être ajustés à différents contextes pathologiques. Nous avons aussi développé toutes les techniques nécessaires à son implantation chez la souris. Cet outil novateur permettra d’approfondir notre connaissance des mécanismes d’action et des mécanismes cellulaires sous-jacents aux effets de la SCP et pourra mener, à long terme, à l’identification de nouvelles cibles thérapeutiques. / Deep brain stimulation (DBS) is a surgical procedure used in the treatment of various pathologies. This system, composed of electrodes implanted in a target area in the brain and of a neurostimulator connected by a wire, allows the delivery of an electrical current in a specific area in the brain. To this day, mechanisms of action and cellular effects resulting from DBS remain poorly understood because of a lack of micro-stimulation tools available in the domain and by the fact that these tools do not properly address requirements of this research. To address this challenge, the objectives of my master’s research were to develop a micro-stimulation system usable in mice and to develop and validate required techniques to make this system work in small-sized rodents. Through this study, we have developed a micro-stimulation system that is : 1) usable in mice, 2) able to sustain a long term chronic stimulation (up to 1 month), 3) similar to those used in human in terms of electrical parameters and 4) offering the possibility of adjusting those parameters to various pathological contexts. We also developed the required techniques for its use in mice. This novel tool will allow to deepen our knowledge on the mechanisms of action and cellular mechanisms underlying DBS effects and possibly lead to the identification of new therapeutic targets.

Current industry practices promote therapeutic use of pulsatile stimulation plates to increase muscle mass, strengthen bone density, reduce stress, and improve overall athletic performance of horses. The first objective of this study was to investigate the effect of vibration stimulation on muscle thickness of the extensor carpi radialis, extensor digitorum longus, gluteus medius, longissimus lumborum, semitendinosus, supraspinatus, and longissimus thoracis, as well as circumference and cross-sectional area of the extensor carpi radialis and extensor digitorum longus. The second objective was to evaluate changes in nutrient foramen thickness, circumference, and area, as well as dorsal cortical thickness of the left third metacarpal in response to vibration stimulation exposure over 56 d. Increases in thickness of the topline muscles and improvement of nutrient foramen parameters of treatment horses give evidence to conclude that vibration stimulation may be a viable therapeutic treatment for stock-type horses on stall rest.

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No description available.

Magnetic nerve stimulation is a non-invasive method of exciting a neural tissue which can be achieved by exposing the body to a transient magnetic field. This field is generated by passing a high current through a coil over a short period of time. By positioning this coil in a specific orientation over the targeted nerve, the time variation of the magnetic field will create an electric field in the conductive milieu of the body. Induced currents will result from that electric field. If those currents reach a certain amplitude within a specific time period this will cause a neural depolarization. This depolarization will enable us to test and examine the excited nerve which will provide us with the necessary data for an effective treatment. In my thesis I will analyse the benefits of magnetic nerve stimulation with the objective of designing a coil that provides a focussed magnetic field. This field will excite the targeted nerve with minimal or to no excitation to the surrounding nerves. This means that we can effectively apply or measure the excitation of the targeted nerve without involving the surrounding nerves. It is my intention to bring this application to a practical platform where a simple circuit with lower power requirements can be used. This will enable some patients requiring physiotherapy to safely administer magnetic nerve stimulation to themselves without the help of a therapist. / Thesis / Master of Engineering (ME)

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The purpose of this study was to examine the effects of multi-modal stimulation (differing amounts of light and vocal stimulation) on preterm infants' behavioral and state organization. Specifically, we looked at the effects that supplemental vocal stimulation (taped female voice) had when varied in amount of exposure (three times a day versus once a day) and when provided in different lighting conditions ("typical illumination" versus "decreased illumination"). Forty infants were placed in one of four groups: Standard Illumination/High Voice (SIHV), Standard Illumination /Low Voice (SILV), Decreased Illumination/High Voice (DIHV) and Decreased Illumination/Low Voice (DILV). Infants receiving standard illumination were exposed to the vocal stimulus in standard NICU lighting conditions (approximately 20 lux), whereas infants in the "low" lighting conditions were exposed to the stimulus in darkened conditions (approximately 3 lux). Infants receiving high vocal stimulation listened to a taped female voice three times a day, whereas infants receiving low vocal stimulation were exposed to the voice only once a day. Each infant received 10 minutes of exposure per session over five consecutive days. Infants were videotaped in their incubator for 10 minutes before, during, and after the stimulus exposure (total of 30 minutes) for each day. The videotapes were then scored on the infant's frequency of stress related behaviors and self-regulatory behaviors before, during, and after the stimulus for each day. Results indicated that both lighting levels and vocal stimulation altered preterm infants' stress and self-regulatory behaviors, and that these effects were dependent on both the day and the stimulus condition the infant was in. In addition, the vocal stimulation and lighting levels had an effect on the states that infants exhibited during and after the presentation of stimulation. These results suggest that the occurrence of different types and amounts of stimulation have an effect on behavioral organization of the preterm infant, and these effects are highly dependent on both history and context in which this stimulation is presented / Ph. D.