Browsing by Subject "Motor control"
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Item Analysis of complex movements(2021-05-08) Liu, Lijia; Ballard, Dana H., (Dana Harry), 1946-; Stone, Peter; Niekum, Scott; Vouga, Etienne; Hayhoe, MaryIn most everyday repetitive movements such as walking, sitting, and reaching, humans exhibit large degrees of regularity. However, at the other end of the movement spectrum, in complex movement tasks, such as retrieving an object from a cluttered environment or choosing balance positions for transporting a large, unwieldy object, humans are inventive problem solvers. Therefore, in the quest to understand the human movement system, it would be essential to know if general movements have regularities across subjects as it would provide an essential scaffold in the development of more detailed dynamic movement models. This research mainly aims to learn the principles behind large-scale arbitrary movements, particularly regarding variations between different subjects. For example, given a goal-directed task, do the movements appear similar across subjects, or are movements very individualized? The tasks for the research covers developing an interactive virtual reality environment to capture goal-directed whole-body human movements, getting insights into the regularities underlying those motion capture data (kinematics), and finally analyzing the corresponding energy cost by using a forty-eight degree of freedom dynamic human model (dynamics). The results illustrate that humans chose trajectories that are economical in energetic cost while accomplishing goal-directed tasks.Item Comparing deep brain stimulation and levodopa as treatment methods for Parkinson’s disease(2011-05) Robbins, Tiffany Paige; Marquardt, Thomas P.; Sussman, Harvey M.This report will review critically the available research on deep brain stimulation and levodopa as a means of treatment for Parkinson’s disease in an attempt to determine why neither of these treatments improves speech.Item Determining how noise and task redundancy influence motor control of planar reaching(2013-12) Nguyen, Hung Phuc, active 2013; Dingwell, Jonathan B.; Seepersad, CarolynMotor noise and redundancy are vexing issues in motor control; yet their understanding provides great insights on underlying control mechanisms that govern movement. They provide glimpses into how the nervous system organizes and regulates movement within the motor control system. Understand of motor control could spur new advances in motor control could lead to better development of rehabilitation process and technology to counteract debilitating affects of neuromuscular disorders and motor readjustment with prostheses. However, before such process and technology could be developed and adapted for clinical use, a deeper understanding of motor control is needed to unravel the neural roadmap that regulates and generates movement. New theory of motor control could precipitate the development of more robust control mechanisms for robotic-human interaction. This work aims at expanding a more rigorous analytical and mathematical framework to understand how these control mechanisms reconcile redundancy and stochastic noise in human motor control.Item Exploring focus of attention in music learning(2020-09-04) Parsons, John E. (Ph. D. in music and human learning); Simmons, Amy L., 1974-; Duke, Robert A; Scott, Laurie P; Pence, Suzanne M; Domjan, Michael PThe acquisition and refinement of complex motor skills requires that learners focus attention strategically in order to optimize performance outcomes. A considerable body of research across a variety of disciplines supports the idea that performers who focus their attention on the external effects of the body’s movements experience enhanced performance outcomes, whereas those who attend more to the movements themselves are disadvantaged. The effects of attentional focus on motor performance are explained, at least in part, by the relationship between focus of attention (FOA) and automatic motor control processes that develop with practice; automaticity allows cognitive resources to be allocated toward the processing of information related to task goals rather than the physical movements associated with the task itself. We understand little about how this phenomenon may function in the initial stages of learning complex skills, such as playing a wind instrument, when learners must attend to the discrete physical components associated with tone production in order to generate more desirable outcomes and establish proper fundamentals. In this dissertation, I report the findings of three studies designed to explore how FOA functions during ongoing instruction and self-directed practice. The first two investigations examined how experienced beginning band teachers instinctively direct students’ attention to internal (e.g., embouchure) and external (e.g., tone) components of performance. In both studies, teachers focused student attention on predominantly internal performance components, but they differed idiosyncratically in how they directed learners’ attention based on concurrent instructional goals and activities. Teachers frequently described relationships between internal and external components of performance (e.g., how embouchure manipulation affects tone), suggesting that they strategically paired physical behaviors with external effects in order to build students’ knowledge of action-outcome relationships. Finally, we examined how undergraduate music education majors enrolled in a brass methods course chose to focus their attention on internal and external elements of performance during self-directed practice on an unfamiliar brass instrument. Analysis of their practice verbalizations revealed that students with extensive training in brass performance reported focusing their attention on predominantly external elements, whereas the less experienced students described focusing on both internal and external elements relatively equally, often noting how their physical actions influenced external outcomes. Taken together, these results suggest that learning and refinement of instrumental performance skills may be optimized when learners’ attention is drawn to action-outcome relationships early in their training. Learners can recruit knowledge of these relationships when troubleshooting performance problems and think critically about how best to achieve musical goals. Classroom music teachers who explicitly verbalize the relationships between internal and external components of performance may therefore increase the efficiency with which students’ skills and independence are cultivated over the long term.Item Redundancy reduction in motor control(2015-12) Johnson, Leif Morgan; Ballard, Dana H. (Dana Harry), 1946-; Miikkulainen, Risto; Neptune, Richard; Peters, Jan; Stone, PeterResearch in machine learning and neuroscience has made remarkable progress by investigating statistical redundancy in representations of natural environments, but to date much of this work has focused on sensory information like images and sounds. This dissertation explores the notions of redundancy and efficiency in the motor domain, where several different forms of independence exist. The dissertation begins by discussing redundancy at a conceptual level and presents relevant background material. Next, three main branches of original research are described. The first branch consists of a novel control framework for integrating low-bandwidth sensory updates with model uncertainty and action selection for navigating complex, multi-task environments. The second branch of research applies existing machine learning techniques to movement information and explores the mismatch between these methods for extracting independent components and the forms of redundancy that exist in the motor domain. The third branch of work analyzes full-body, goal-directed reaching movements gathered in a novel laboratory experiment, using explicitly measured information about the goal of each movement to uncover patterns in the movement dynamics. Each branch of research explores redundancy reduction in movement from a different perspective, building up a sort of catalog of the types of information present in movements. Redundancy is discussed throughout as an an important aspect of movement in the natural world. The dissertation concludes by summarizing the contributions of these three branches of work, and discussing promising areas for future work spurred by these investigations. More detailed models of voluntary movements hold promise not only for better treatments, improved prosthetics, smoother animations, and more fluid robots, but also as an avenue for scientific insight into the very foundations of cognition.Item Static and dynamic performance during precision fine motor tracking(2013-05) Gottlich, Samantha; Abraham, Lawrence D.Studies of static and dynamic motor control have a long research history. In most cases, studies have focused on one condition or the other. However, it is important to determine whether differences exist between the two types of task, especially when used in conjunction with task performance. Video game controllers, motorized wheel chairs, steering wheels, and robotic surgical equipment are all examples of how modern equipment uses static and dynamic motor control to achieve task performance goals. To this end, this study aimed to examine possible differences in accuracy or consistency of performance between static and dynamic variations of a precision fine motor tracking task. Nineteen healthy, right-handed volunteer participants were asked to manipulate a cursor to track a moving target with both index fingers, using a static control method in one task and a dynamic control method in another task. The cursor was to follow as closely as possible a target traveling along a diagonal line and back. The control methods were tested during two different testing sessions to reduce confounding of the task conditions. After 50 practice trials in a condition, 5 test trials were recorded. Two dependent variables, RMSE and CVE, were used to represent task performance as indicators of accuracy and consistency, respectively. Analyses of variance with a Latin Square design were used to compare overall performance of each dependent variable between the two conditions. Results showed a significant difference in both variables with p-values less than .001; tracking accuracy was better on the static task and cursor motion consistency was better on the dynamic task. These findings suggest that performance aspects of a fine motor control task does vary with control method and can be used to aid equipment design and task performance in the future.Item The central strategy of music practice(2023-08-17) Killion, Micah Furey; Duke, Robert A.; Simmons, Amy L; Jellison, Judith A; Scott, Laurie P; West, Justin J; Schroeder-Arce, RoxanneIndividual practice is a ubiquitous component of all musicians’ lives, and music pedagogues for centuries have offered prescriptions to aspiring musicians regarding effective music practice. These prescriptions are often characterized as practice strategies, yet they often fail to precisely convey the moment-to-moment process of skill learning, one that embodies iterative sequences of prediction (intention), performance, perception, and adaptation. There is as yet no systematic research that documents the behavior of artist-level performers engaged in successful individual practice. I conducted two investigations, the first of which is a detailed analysis of the individual practice of six artist-level trumpet players. The second examined student musicians’ observation of expert practice. In the first study, six artist-level trumpet players submitted video recordings of their practice during which they rehearsed passages of music they had not yet mastered. The recordings were analyzed in detail to document how the artists allocated time, responded to discrepancies between intentions and outcomes, and organized practice activities to effect moment-to-moment changes in their playing. The results reveal that expert practice can be analyzed and described in terms of one central strategy: formulating vivid goals, performing, perceiving discrepancies between intentions and outcomes, and adapting subsequent performance trials to render momentary challenges surmountable. This is followed by iterations in which expert musicians adjust the parameters of each succeeding performance trial in ways that reduce the discrepancy between intentions and outcomes while maintaining a high percentage of successful performance trials. Three representative excerpts from the recordings used in first study served as stimuli for the second study. The excerpts were viewed by three groups of observers: undergraduate trumpet students, graduate trumpet students, and the six professionals who participated in the first study. Participants were interviewed to explore the extent to which they noticed the central strategy the experts used to refine their skills. There were stark differences between the observations of experts and those of nonexperts. Throughout the experts’ comments were indications of their recognizing what I describe as the central strategy of music practice. Student musicians seldom commented in ways that reflected recognition of this strategy.Item A theoretical neuro-biomechanical model of proprioceptive control for lower extremity movement(2012-08) Jin, Hiroshi; Barr, Ronald E.; Arapostathis, Ari, 1954-; Womack, Baxter F.; Neptune, Richard R.; Sreenivasan, S VA computational neural and biomechanical system for human bicycle pedaling is developed in order to study the interaction between the central nervous system and the biomechanical system. It consists of a genetic algorithm, artificial neural network, muscle system, and skeletal system. Our first finding is that the genetic algorithm is a robust tool to formulate human movement. We also find that our developed models are able to handle mechanical perturbation and neural noise. In addition, we observe variability and repeatability of pedaling motion with or without perturbation and noise. Movement phase dependent feedback nature is seen through computation too. This system shows many human movement qualities and is useful for further neural and motor control investigations.Item Trial-to-trial dynamics and learning in generalized, redundant reaching tasks(2010-08) Smallwood, Rachel Fay; Dingwell, Jonathan B.; Abraham, Lawrence D.Trial-to-trial variability in human movement is often overlooked and averaged out, but useful information can be gleaned on the brain’s control of variability. A task can be defined by a function specifying a solution manifold along which all task variable combinations will lead to goal success – the Goal-Equivalent Manifold (GEM). We selected a reaching task with variables reach Distance (D) and reach Time (T). Two GEMs were selected: a constant D/T and constant D×T. Subjects had no knowledge of the goal prior to the experiments and were instructed only to minimize error. Subjects learned the generalized tasks by reducing errors and consolidated learning from one day to the next, generalized learning from the D×T to the D/T GEM, and had interference of learning from the D/T to the D×T GEM. Variability was structured along each GEM significantly more than perpendicular to it. Deviations resulting in errors were corrected significantly more quickly than any other deviation. Our results indicate that subjects can learn generalized reaching tasks, and the brain exploits redundancy in those tasks.