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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Novel strategies for the modulation and investigation of memories in the hippocampus

Rahsepar, Bahar 26 January 2022 (has links)
Disruptions of the memory systems in the brain are linked to the manifestation of many neuropsychiatric diseases such as Alzheimer’s disease, depression, and post-traumatic stress disorder. The limited efficacy of current treatments necessities the development of more effective therapies. Neuromodulation has proven effective in a variety of neurological diseases and could be an attractive solution for memory disorders. However, the application of neuromodulation requires a more detailed understanding of the network dynamics associated with memory formation and recall. In this work, we applied a combination of optical and computational tools in the development of a novel strategy for the modulation of memories, and have expanded its application for interrogation of the hippocampal circuitry underlying memory processing in mice. First, we developed a closed-loop optogenetic stimulation platform to activate neurons implicated in memory processing (engram neurons) with a high temporal resolution. We applied this platform to modulate the activity of engram neurons and assess memory processing with respect to synchronous network activity. The results of our investigation support the proposal that encoding new information and recalling stored memories occur during distinct epochs of hippocampal network-wide oscillations. Having established the high efficacy of the modulation of engram neurons’ activity in a closed-loop fashion, we sought to combine it with two-photon imaging to enable high spatial resolution interrogation of hippocampal circuitry. We developed a behavioral apparatus for head-fixed engram modulation and the assessment of memory recall in immobile animals. Moreover, through the optimization of dual color two-photon imaging, we improved the ability to monitor activity of neurons in the subfields of the hippocampus with cellular specificity. The platform created here will be applied to investigate the effects of engram reactivation on downstream projections targets with high spatial and cell subtype specificity. Following these lines of investigations will enhance our understanding of memory modulation and could lead to novel neuromodulation treatments for neurological disorders associated with memory malfunctioning.
2

Regulating the anterior medial prefrontal cortex : exploratory investigation of real-time fMRI training

Smith, Rachelle Marie 11 1900 (has links)
The feasibility of using real-time functional magnetic resonance imaging (fMRI) feedback regarding the level of activation in rostromedial prefrontal cortex (rMPFC) to learn improved regulation of this brain area was examined in a group of 5 young adults. Subjects received real-time feedback from the target brain region while engaging in a blocked-design task involving alternating blocks of attempted up-regulation and down-regulation of the target brain region. A transient negative emotional state was induced prior to each scanning session. Subjects completed 6 scanning sessions (a pre-training session, 4 feedback sessions and a post-training session - no feedback was provided for pre and post-training sessions). The guideline strategy provided to subjects of engaging in emotional awareness during up-regulation and bodily awareness during down-regulation was found to consistently regulate the region in the pre-training session prior to the fMRI feedback sessions. This finding is in line with the previously proposed role of the rMPFC in emotional awareness. In contrast to previous real-time fMRI findings, greater recruitment of the region was observed in the pre-training session compared to the post-training session, with a non-significant negative trend observed across feedback sessions. These results suggest that there may be limitations to which the feedback techniques successfully employed for other brain regions extend to yet unexplored brain regions.
3

Regulating the anterior medial prefrontal cortex : exploratory investigation of real-time fMRI training

Smith, Rachelle Marie 11 1900 (has links)
The feasibility of using real-time functional magnetic resonance imaging (fMRI) feedback regarding the level of activation in rostromedial prefrontal cortex (rMPFC) to learn improved regulation of this brain area was examined in a group of 5 young adults. Subjects received real-time feedback from the target brain region while engaging in a blocked-design task involving alternating blocks of attempted up-regulation and down-regulation of the target brain region. A transient negative emotional state was induced prior to each scanning session. Subjects completed 6 scanning sessions (a pre-training session, 4 feedback sessions and a post-training session - no feedback was provided for pre and post-training sessions). The guideline strategy provided to subjects of engaging in emotional awareness during up-regulation and bodily awareness during down-regulation was found to consistently regulate the region in the pre-training session prior to the fMRI feedback sessions. This finding is in line with the previously proposed role of the rMPFC in emotional awareness. In contrast to previous real-time fMRI findings, greater recruitment of the region was observed in the pre-training session compared to the post-training session, with a non-significant negative trend observed across feedback sessions. These results suggest that there may be limitations to which the feedback techniques successfully employed for other brain regions extend to yet unexplored brain regions.
4

Regulating the anterior medial prefrontal cortex : exploratory investigation of real-time fMRI training

Smith, Rachelle Marie 11 1900 (has links)
The feasibility of using real-time functional magnetic resonance imaging (fMRI) feedback regarding the level of activation in rostromedial prefrontal cortex (rMPFC) to learn improved regulation of this brain area was examined in a group of 5 young adults. Subjects received real-time feedback from the target brain region while engaging in a blocked-design task involving alternating blocks of attempted up-regulation and down-regulation of the target brain region. A transient negative emotional state was induced prior to each scanning session. Subjects completed 6 scanning sessions (a pre-training session, 4 feedback sessions and a post-training session - no feedback was provided for pre and post-training sessions). The guideline strategy provided to subjects of engaging in emotional awareness during up-regulation and bodily awareness during down-regulation was found to consistently regulate the region in the pre-training session prior to the fMRI feedback sessions. This finding is in line with the previously proposed role of the rMPFC in emotional awareness. In contrast to previous real-time fMRI findings, greater recruitment of the region was observed in the pre-training session compared to the post-training session, with a non-significant negative trend observed across feedback sessions. These results suggest that there may be limitations to which the feedback techniques successfully employed for other brain regions extend to yet unexplored brain regions. / Arts, Faculty of / Psychology, Department of / Graduate
5

Poi Poi Revolution: A real-time feedback training system for objectmanipulation

Walker, Ryan Christopher Gareth January 2013 (has links)
The affordability and availability of fast motion cameras presents an ideal opportunity to build computer systems that create real-time feed- back loops. These systems can enable users to learn at a faster rate than traditional systems, as well as present a more engaging experience. In this dissertation, I document the development and evaluation of a real- time audio and visual feedback system for geometric poi manipulation. The goal of the system is to present an experiential and objectively su- perior learning tool when compared to traditional learning techniques in the object manipulation community. For the evaluation, I conduct an experiment that compares the feedback training system with traditional learning techniques in the object manipulation community. The results suggest that the feedback system presents a more engaging experience than traditional mirror feedback training, and conclude that further re- search is warranted.
6

Household energy use in South Africa : a systemic study of an individual intervention

Du Preez, Mathilda January 2015 (has links)
The world-wide problem of increasing greenhouse gas emissions has received considerable attention in recent decades. In South Africa, several factors necessitate residential energy efficiency research. These include the high levels of pollution caused by the generation of electricity with low quality coal, which is fairly readily available, the increasing consumer base since 1994, and electricity price increases of 20% per annum since 2008. This study investigates qualitative and quantitative aspects of energy efficiency strategies employed in 41 South African households from diverse socio-economic backgrounds, within the Pretoria region. Field work was conducted during 2010 and 2011. This research was conducted using a multi-phased combined experimental and ex post facto mixed methodology. Actual electricity consumption levels were recorded in all participating households, which were divided into two experimental groups, but only participants in the first experimental group participated in an interview and intervention to reduce electricity consumption. Measurements were followed by focus group sessions open to all participants. Thematic analysis was used to identify participants’ main strategies for energy efficiency, and the effectiveness of these strategies was quantified. The qualitative and quantitative findings are discussed both separately from and in conjunction with one another. Feedback was shown to be a key factor in enabling behaviour change. Needs not only for information but for guidance in its interpretation are highlighted, particularly where literacy levels are lower. Erroneous beliefs about the functioning of appliances were identified and quantified. Winter was identified as the best time to introduce an intervention and improve energy savings due to the ‘normal’ steep increase during that time. Popular and effective strategies employed in households to reduce electricity consumption were also identified. This study culminates in a theoretical model, placing the micro, meso and exo implications of residential energy efficiency in a cyclical empowerment model of environmental concern, the need for information, behaviour change and the resulting need for feedback. Suggestions for policy development and future research are made focussing specifically on the role of females in designing energy efficiency measures, measuring quality of life and not just kWhs and emphasising the importance of real-time feedback on consumption. / Thesis (PhD)--University of Pretoria, 2015. / Psychology / Unrestricted
7

HUMAN ACTIVITY TRACKING AND RECOGNITION USING KINECT SENSOR

Lun, Roanna January 2017 (has links)
No description available.
8

A Human Side Of The Smart Grid: Behavior-Based Energy Efficiency From Renters Using Real-Time Feedback And Competitive Performance-Based Incentives

Fredman, Daniel 01 January 2018 (has links)
Our energy system is rapidly transforming, partially due to advances in internet and communications technologies that leverage an unprecedented amount of data. Industry proponents of the so-called “smart grid” suggest these technologies facilitate deeper engagement with end-users of energy (utility customers) that can in turn drive behavior-based changes and accelerate a renewable energy transition. While there has been progress in understanding how these technologies change consumer behavior using, for example, real-time feedback, it’s unclear how specific segments (e.g., renters) respond to these interventions; it’s also unclear why feedback is, or is not, producing changes in energy consumption. The literature suggests that behavioral strategies (e.g. information feedback, competitions, incentives) coupled with technology may present a way for utilities and efficiency programs to create savings—expanding opportunities for those often underserved by traditional approaches, such as renters—yet this coupling is not well understood, neither broadly (for all end users) nor specifically (for renters). This dissertation builds upon that literature and explores a human side of the smart grid, using a field experiment in renter households to test the interacting effects of real-time energy feedback and a novel form of financial incentive, referred to here as a competitive performance-based incentive. The experiment had two phases: phase one tested the feedback against a control group; phase two tested feedback, the incentive, and a combined treatment, against a control group. Results of these interventions were measured with pre- and post-treatment surveys as well as observed electricity consumption data from each household’s smart meter. The results of this experiment are described in three papers. Paper one examines the interventions’ individual and combined effectiveness at motivating renters to reduce or shift timing of electricity consumption. Feedback alone produced a significant savings effect in phase one. In phase two, the effect of the feedback wore off; the incentive alone had no significant effect; and the group that received feedback and the incentive experienced a doubling of savings relative to the effect of feedback alone, as observed in phase one. Paper two uses pre- and post-intervention survey data to examine how individual perceptions of energy change as a result of the interventions. Perception of large energy-using appliances changed the most in households that received feedback, suggesting that better information may lead to more effective behavior changes. Paper three leverages the results of the first two components to evaluate the policy implications and impacts on demand side management for utilities, efficiency programs, and the potential for behavior-based energy efficiency programs. Advocates of the smart grid must recognize the technology alone cannot produce savings without better engagement of end-users. Utility rate designers must carefully consider how time-based rates alone may over-burden those without the enabling technology to understand the impact of their energy choices.
9

Utility of Feedback Given by Students During Courses

Atkisson, Michael Alton 01 July 2017 (has links)
This two-article dissertation summarizes the end-of-course survey and formative feedback literatures, as well as proposes actionability as a useful construct in the analysis of feedback from students captured in real-time during their courses. The present inquiry grew out of my work as the founder of DropThought Education, a Division of DropThought. DropThought Education was a student feedback system that helped instructional designers, instructors, and educational systems to use feedback from students to improve learning and student experience. To find out whether the DropThought style of feedback was more effective than other forms of capturing and analyzing student feedback, I needed to (1) examine the formative feedback literature and (2) test DropThought style feedback against traditional feedback forms. The method and theory proposed demonstrates that feedback from students can be specific and actionable when captured in the moment at students' activity level, in their own words. Application of the real-time feedback approach are relevant to practitioners and researchers alike, whether an instructor looking to improve her class activities, or a learning scientist carrying out interventionist, design-based research.
10

Assistierte Bewegungskontrolle in der Rehabilitation durch intelligente Sensortechnologie

Nitzsche, Nico, Hirtz, Gangolf, Schulz, Henry 13 November 2018 (has links)
Im Beruf, in der Freizeit und in der Rehabilitation werden immer öfter digitale Medien eingesetzt. Speziell in der motorischen Rehabilitation wird zunehmend eine Digitalisierung der Therapieprozesse festgestellt. Dieser Trend soll den Therapieprozess dokumentieren, die Patienten motivieren und auch eine Unterstützung für die Therapeuten sein. Gegenwärtig werden in der Praxis verschiedene „Feedback-Informationen“ verwendet, beispielsweise Informationen zum Bewegungsweg und zur Bewegungsgeschwindigkeit. In der Regel kommen diese Informationen primär vom Trainingsgerät, da dort die entsprechenden Sensoren angebracht sind. Die Information zur Bewegungsqualität des Patienten selbst, wird von den Sensoren nicht erfasst. Im Rahmen des Projektes „AssiSt“ (Assistierte Bewegungskontrolle in der Rehabilitation durch intelligente Sensortechnologie) wurde ein anderer Ansatz verfolgt. Hier war es das Ziel, ein Assistenzsystem zu entwickeln, welches einem Patienten während seiner Übungsausführung Feedback geben kann. Es galt dabei zu prüfen, inwiefern mit einem optischen Sensor die Bewegung des Übenden direkt erfasst und in Echtzeit auf fehlerhafte Bewegungsausführungen/oder die/eine fehlerhafte Bewegungsausführung analysiert werden kann. Eine falsche Bewegungsausführung kann dazu führen, dass die Zielmuskulatur nicht richtig angesteuert wird. Darüber hinaus können aktive und passive Strukturen in der frühen postoperativen Phase überlastet werden. Hierfür wurde mithilfe von Methoden des maschinellen Lernens die Bewegung des Übenden auf Fehlerbilder hin analysiert. Bei fehlerhafter Ausführung werden dabei über eine Feedbackeinheit sofort Korrekturhinweise übermittelt, sodass auftretende Fehler zeitnah korrigiert werden können. Im Verlauf klinischer Tests wurde das Feedback des Assistenzsystems mit der Analyse eines Therapeuten verglichen, wobei eine gute Übereinstimmung erzielt wurde. Neben der Bewegungsanalyse wird durch das System zusätzlich eine Verlaufsdokumentation erstellt, sodass Patienten und Therapeuten nachträglich den Therapieverlauf auswerten können. Darüber hinaus wurde untersucht, ob Biosignale, wie bspw. die Erwärmung der Hautoberfläche infolge der Muskelarbeit während des Trainings, als Feedback geeignet sind. Dies könnte das Effektwissen des Patienten durch ein besseres Verständnis zwischen der Therapieübung und der Muskelansteuerung verbessern.

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