Browsing by Subject "Motor ability"
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Item Comparison between the strength index test and predicted dynamic strength test as predictors of motor ability(Texas Tech University, 1968-06) Bowe, Gary DonNot availableItem The coordinated plasticity of astrocytes and synapses in learning and post-stroke recovery(2011-05) Kim, Soo Young, 1980-; Jones, Theresa A.; Gore, Andrea C.; Harris, Kristen M.; Schallert, Timothy; Delville, YvonStroke typically occurs in one hemisphere and often results in long-term disability in the contralateral body side (paretic side). Greater reliance on the non-paretic body side is used to compensate for this disability. Meanwhile, the brain undergoes degenerative and plastic changes in both hemispheres. Many previous studies have investigated post-stroke brain plasticity, and explored how it is shaped by behavioral experiences, to better understand the mechanisms of functional recovery. However, these studies have primarily focused on neurons and synapses. Given the abundant evidence that astrocytes actively control activity and plasticity of synapses, it seems reasonable to investigate how astrocytes are involved in behavior- and injury-driven brain plasticity. The central hypothesis of these studies is that synaptic plasticity underlying motor skill learning and post-stroke motor rehabilitation is coordinated with structural and functional plasticity of perisynaptic astrocytes. This was tested in a rat model of motor learning and "re-learning" after unilateral stroke-like damage to sensorimotor cortex. In the contralesional homotopic cortex, astrocytic volume varied with lesion size, as did the number of synapses. In the remaining motor cortex of the injured hemisphere, rehabilitative training with the paretic limb increased the proportion of astrocytic membrane apposed with synapses along with density of synapses. Furthermore, the percentage of synapses with astrocytic contacts was significantly correlated with functional outcome. Training with the non-paretic limb also induced greater synaptic density than controls in peri-infarct cortex, but functional outcome was negatively correlated with this and was not correlated with astrocytic contacts with synapses. These findings suggest that plasticity of, and association between, synapses and astrocytes vary with the type of experiences. Moreover, pharmacological upregulation of astrocytic glutamate uptake, which is one of the key ways that astrocytes modulate synaptic activity, interfered with functional recovery, supporting a critical role for astrocytic glutamate uptake in functional outcome following a stroke. Taken together, these studies contribute to better understanding of how lesions and experiences affect plasticity of astrocytes and synapses. These findings suggest that post-injury experiences alter astrocytic association with synapses, and that the coordinated plasticity of astrocytes and synapses is likely to be a critical mediator to functional outcome.Item Examination of dexterity as a function of hand size and occupation using the Purdue Pegboard(Texas Tech University, 1996-01) Pearce, AdrienneThe purpose of this study was to examine potential differences in the level of dexterity between large handed individuals and small handed individuals. Each subject's hand size was determined by measuring palmar girth. Palmar girth measurements greater than one standard deviation from the mean palmar girth were classified as large and the palmar girth measurements at least one standard deviation below the mean palmar girth were classified as small hand size. The subjects included males from an agrarian population and from an industrial population. The Purdue Pegboard was used to test bilateral hand dexterity. Each subject performed the Purdue Pegboard test according to established testing procedures. Results were examined to determine if any differences in performance were evident between occupations and between larger sized hands versus smaller sized hands. Additionally, results were examined in terms of whether there was a particular occupation that comprised the larger hand size group. Although a difference was found in performance between groups (agrarian and industrial), no difference in performance was found as a function of hand size. Also, the agrarian population was not identified as having predominantly large hands as compared with the industrial population.Item Human motor unit synchrony and its relation to force steadiness(2007) Terry, Charles Kevin, 1961-; Griffin, Lisa; Rylander, H. Grady (Henry Grady), 1948-Motor unit synchronization is phenomenon driven by a common input that results in the near-simultaneous firing of two or more motor units, which is referred to as short-term synchronization. The relationship between motor unit synchronization and force steadiness is still unclear, even after numerous experiments and simulations. Our main hypothesis was that the decreased force tetanus brought on by motor unit synchronization would be correlated to reduced steadiness at very low hand muscle forces. To determine if this correlation existed, young, healthy adults performed a submaximal, isometric pinch at four forces to determine if motor unit synchronization increased with a progressive decrease in force steadiness driven by reduced force levels. However, before performing synchronization analyses, we had to establish the best technique for measuring motor unit coherence, which quantifies the strength and frequency of a periodic common input. We used a pool of simulated spike trains with various firing rates, coefficients of variation (CV), common input frequencies and trial durations to explore the effects of data segmentation and spike train properties on coherence. We found that tapered segments overlapped by at least 50% maximized coherence measurements, regardless of taper type and that increasing common input frequency CV from 0.15-0.50 made coherence measurements unusable, even at high synchronization levels. During an isometric pinch at 2, 4, 8, and 12% of maximum digit force, we recorded thumb and index finger forces and EMG from the first dorsal interosseous (FDI) and adductor pollicis (AdP) muscles. As expected, the force CV dropped as each digit force increased. Pooled coherence revealed a dominant peak for the 2-10 Hz, but power for both digits' forces was limited to the 0-2 Hz bandwidth. There was a weak correlation for thumb force CV and coherence for within-AdP pairs, but no significant correlations were found for within-FDI pair coherence and finger force CV. Therefore, motor unit synchronization was not a strong driver of force steadiness for this protocol. To ensure that inherent firing rate nonstationarity of spike train data did not affect coherence measurements, we produced a new set of spike train pairs with firing rates and variances that approximated those for physiological motor units, which varied from 0-25%. Stationarity level was not significantly correlated to peak coherence (max R² = 0.082). Therefore, coherence measurements of spike train data with characteristics similar to those of the simulated trains were not significantly affected by nonstationarity. The establishment of the best method for computing coherence, the lack of a strong correlation between force steadiness and motor unit synchronization for submaximal isometric forces, and the knowledge that spike train nonstationarity has no significant effect on coherence measurements are all important discoveries needed for progress in the areas of basic neuromuscular function, motor unit synchronization, and pathological force unsteadiness.Item Item Motor ability and mental ability in grades four and five(Texas Tech University, 1967-05) Prichard, Jimmy CharlesNot availableItem Motor speed and tactile perception in children and adolescents with nonverbal learning disabilities(2006) Wilkinson, Alison Diane; Semrud-Clikeman, MargaretItem Selected motor movements as an indicator of rhythmic capacity(Texas Tech University, 1976-08) Brand, Diane CNot availableItem The assessment of complex, human, perceptual-psychomotor abilities(Texas Tech University, 1974-05) Waldeisen, Lewis EdwardNot availableItem The Effect of Peer Performance Feedback Upon Learning a Simple Motor Skill(Texas Tech University, 1971-08) Johnson, Robert WilliamsNot Available.Item The effect of vibration on certain psychomotor responses(Texas Tech University, 1964-05) Clemens, David EarlNot availableItem The effect of weight training on selected human movement time(Texas Tech University, 1969-12) Davis, Richard EdwardNot availableItem The effects of a trampoline class on cardiovascular fitness, leg power, vertical jumping height, and leg strength(Texas Tech University, 1966-08) Tillinghast, JackNot availableItem The effects of rigid container height and shape on maximum acceptable weight of lift(Texas Tech University, 1988-12) Ostrom, Lee ThomasPsychophysical lifting capacity studies have examined many variables affecting lifting capacity, i.e., box width in the sagittal plane, box length in the frontal plane, the use of handles on the box, and the type of container (bag or box). The effects of box height and the shape of rigid containers were not studied before now. The major objectives of this study were: 1) To compare the results of a psychophysical box lifting task with the results of a psychophysical cylinder lifting task, and 2) To determine if container height has an effect on the maximum acceptable weight of lift. The minor objectives of this study were: 1) To determine whether a ten session training program was adequate for female subjects, and 2) To determine if the results of the isoinertial incremental 6-foot lift strength test are affected by training. Five male and five female university students participated as subjects in the study. A training program was conducted prior to the experimental portion of this study. The training program consisted of cardiovascular training, muscular endurance training, muscular strength training, and flexibility training. There were two experiments in this study. The first experiment was a psychophysical box lifting experiment. The independent variables in this study were box height (12, 24 and 36 inches), frequency of lift (6, 9 and 12 lifts/min.), and lift range (floor to knuckle, knuckle to shoulder and floor to shoulder). The dependent variables were VO2, Borg*s rating of perceived exertion and maximum acceptable weight of lift (MAWL). The second experiment was a psychophysical cylinder lifting experiment. The independent and dependent variables were the same as for the first experiment. Linear regression models developed to predict MAWL for boxes with heights greater than 12 inches using the MAWL for a 12-inch box were developed.Item The performance of trainable and educable retardates on the Visual Discrimination Test(Texas Tech University, 1977-08) O'Donnell, Carol ANot availableItem The relationship of selected psychological characteristics to physical fitness and motor ability(Texas Tech University, 1970-08) Kaerwer, Bobby NewtonNot available