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- Creators: College of Health Solutions
- Creators: Rahman, Qasim
- Creators: Beloozerova, Irina N
Description
Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has been mostly ignored. Characterizing the influence of arm configuration (i.e. intrinsic factors) would allow greater comprehension of sensorimotor integration and assist in interpreting exaggerated movement variability in patients. In this study, subjects were placed in a 3-D virtual reality environment and were asked to move from a starting position to one of three targets in the frontal plane with and without visual feedback of the moving limb. The alternating of visual feedback during trials increased uncertainty between the planning and execution phases. The starting limb configurations, adducted and abducted, were varied in separate blocks. Arm configurations were setup by rotating along the shoulder-hand axis to maintain endpoint position. The investigation hypothesized: 1) patterns of endpoint variability of movements would be dependent upon the starting arm configuration and 2) any differences observed would be more apparent in conditions that withheld visual feedback. The results indicated that there were differences in endpoint variability between arm configurations in both visual conditions, but differences in variability increased when visual feedback was withheld. Overall this suggests that in the presence of visual feedback, planning of movements in 3D space mostly uses coordinates that are arm configuration independent. On the other hand, without visual feedback, planning of movements in 3D space relies substantially on intrinsic coordinates.
ContributorsRahman, Qasim (Author) / Buneo, Christopher (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has been mostly ignored. Characterizing the influence of arm configuration (i.e. intrinsic factors) would allow greater comprehension of sensorimotor integration and assist in interpreting exaggerated movement variability in patients. In this study, subjects were placed in a 3-D virtual reality environment and were asked to move from a starting position to one of three targets in the frontal plane with and without visual feedback of the moving limb. The alternating of visual feedback during trials increased uncertainty between the planning and execution phases. The starting limb configurations, adducted and abducted, were varied in separate blocks. Arm configurations were setup by rotating along the shoulder-hand axis to maintain endpoint position. The investigation hypothesized: 1) patterns of endpoint variability of movements would be dependent upon the starting arm configuration and 2) any differences observed would be more apparent in conditions that withheld visual feedback. The results indicated that there were differences in endpoint variability between arm configurations in both visual conditions, but differences in variability increased when visual feedback was withheld. Overall this suggests that in the presence of visual feedback, planning of movements in 3D space mostly uses coordinates that are arm configuration independent. On the other hand, without visual feedback, planning of movements in 3D space relies substantially on intrinsic coordinates.
ContributorsRahman, Qasim (Author) / Buneo, Christopher (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
The primary goal of this study is to assess and develop an understanding of the effects of Assisted Cycling Therapy on manual motor performance in children with Down syndrome. Seven children (Mage 11.6 years old) completed a 30-minute cycle session 2x/week for 8 weeks on the PACT bicycle at a 35% greater rate than their self-selected rate. Pre- and post-testing of grip force with a dynamometer and unimanual and bimanual manual dexterity using the Purdue Pegboard were measured to determine changes in force production and fine motor control, respectively. Results consistently showed improvements in grip force in both hands and bimanual dexterity following PACT. My results are interpreted with respect to cerebral lateralization and neuroplasticity following PACT intervention.
ContributorsGunther, Bryn (Author) / Ringenbach, Shannon (Thesis director) / Ofori, Edward (Committee member) / Rand, Miya (Committee member) / Rafie, Fourozan (Committee member) / Barrett, The Honors College (Contributor) / College of Health Solutions (Contributor)
Created2023-05
Description
Locomotion in natural environments requires coordinated movements from multiple body parts, and precise adaptations when changes in the environment occur. The contributions of the neurons of the motor cortex underlying these behaviors are poorly understood, and especially little is known about how such contributions may differ based on the anatomical and physiological characteristics of neurons. To elucidate the contributions of motor cortical subpopulations to movements, the activity of motor cortical neurons, muscle activity, and kinematics were studied in the cat during a variety of locomotion tasks requiring accurate foot placement, including some tasks involving both expected and unexpected perturbations of the movement environment. The roles of neurons with two types of neuronal characteristics were studied: the existence of somatosensory receptive fields located at the shoulder, elbow, or wrist of the contralateral forelimb; and the existence projections through the pyramidal tract, including fast- and slow-conducting subtypes.
Distinct neuronal adaptations between simple and complex locomotion tasks were observed for neurons with different receptive field properties and fast- and slow-conducting pyramidal tract neurons. Feedforward and feedback-driven kinematic control strategies were observed for adaptations to expected and unexpected perturbations, respectively, during complex locomotion tasks. These kinematic differences were reflected in the response characteristics of motor cortical neurons receptive to somatosensory information from different parts of the forelimb, elucidating roles for the various neuronal populations in accommodating disturbances in the environment during behaviors. The results show that anatomical and physiological characteristics of motor cortical neurons are important for determining if and how neurons are involved in precise control of locomotion during natural behaviors.
Distinct neuronal adaptations between simple and complex locomotion tasks were observed for neurons with different receptive field properties and fast- and slow-conducting pyramidal tract neurons. Feedforward and feedback-driven kinematic control strategies were observed for adaptations to expected and unexpected perturbations, respectively, during complex locomotion tasks. These kinematic differences were reflected in the response characteristics of motor cortical neurons receptive to somatosensory information from different parts of the forelimb, elucidating roles for the various neuronal populations in accommodating disturbances in the environment during behaviors. The results show that anatomical and physiological characteristics of motor cortical neurons are important for determining if and how neurons are involved in precise control of locomotion during natural behaviors.
ContributorsStout, Eric (Author) / Beloozerova, Irina N (Thesis advisor) / Dounskaia, Natalia (Thesis advisor) / Buneo, Christopher A (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2015
Description
Reactive step and treadmill perturbation training have been shown to improve first step measurements and reduce falls. However, the effect of variable training on the efficacy of generalization is poorly understood. The objective of this study was to measure whether the addition of variability in the perturbation training protocol can increase the amount of generalization seen in forward perturbations. The study included 28 young, healthy adults between the age of 20-35 years old with no known significant medical history. Fifteen participants underwent constant training in one direction with the same belt acceleration (4 m/s2) and thirteen participants underwent variable training where their foot positioned and belt acceleration (3 m/s2, 4 m/s2, 5 m/s2) were randomized throughout the collections All slips were done in the forward direction requiring a forward reactive step. To assess the effects of variable training an independent sample t-test of the differences in generalization between each group was calculated. Primary outcome variables in both studies were margin of stability (MOS), step length, and step latency. Results from the study indicated that variable training made no significant improvement (p<0.05) in generalization across the variables. The P-values for the difference in generalization of MOS, step length, and step latency were 0.635, 0.225, 0.148 respectively. Despite the lack of significant evidence to support improvement in generalization with variable training, further investigations are warranted to develop training methods capable of reducing falls in at risk populations.
ContributorsArroyo, Randall Adrian (Author) / Peterson, Daniel (Thesis director) / Ofori, Edward (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05