Matching Items (5)
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- All Subjects: Brains
- Creators: Doane, Leah
- Creators: Rahman, Qasim
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
This study examined the cross-sectional and longitudinal associations among diurnal cortisol rhythms and sleeping patterns in adolescents. 79 participants completed the study over three days during the spring semester of their senior year in high school, and 76 of these subjects participated again over three days during the fall semester of their freshman year in college. They completed daily saliva samples and diary entries, while wearing an actigraph to obtain objective measurements of sleep duration and efficiency. Cross-sectionally, longer sleep duration was associated with a lower cortisol awakening response, a smaller area under the cortisol curve, and a steeper cortisol slope. Longitudinally, there was no significant relationship between sleep duration and these cortisol parameters. Moreover, sleep efficiency was not associated with cortisol parameters cross-sectionally nor longitudinally. Results suggest associations between concurrent sleep duration and cortisol patterns, and may have significant impact on understanding adolescents' physiological response to stress.
ContributorsLathrop, Devon Olivia (Author) / Doane, Leah (Thesis director) / Orchinik, Miles (Committee member) / Zeiders, Katherine (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Stress in individuals presents in various forms and may accumulate across development to predict maladaptive physical and psychological outcomes, including greater risk for the onset of internalizing symptoms. Early life stress, daily life experiences, and the stress response of the hypothalamic-pituitary-adrenal (HPA) axis have all been examined as potential predictors of the development of psychopathology, but rarely have researchers attempted to understand the covariation or interaction among these stress domains using a longitudinal design when looking at the influence of stress on internalizing psychopathology. Further, most research has examined these processes in adulthood or adolescence with much less attention given to the influence of these dynamic stress pathways in childhood. Guided by the biopsychosocial model of stress, this study explored early life stress, daily life stress, diurnal cortisol (cortisol AM slope), and internalizing symptoms in a racially/ethnically and socioeconomically diverse sample of twins participating in an ongoing longitudinal study (N=970 children; Arizona Twin Project; Lemery-Chalfant et al. 2013). An additive model of stress and a stress sensitization framework model were considered as potential pathways of stress to internalizing symptoms in middle childhood. Based on a thorough review of relevant literature, it was expected that each stress indicator would individually predict internalizing symptoms. It was also predicted that early life stress would moderate the associations between diurnal cortisol and internalizing symptoms, as well as daily life stress and internalizing symptoms. Multilevel modeling analyses showed that early life stress and cortisol AM slope, but not daily life stress, predicted internalizing symptoms. Early life stress did not moderate the associations between daily life stress and internalizing symptoms or cortisol AM slope and internalizing symptoms. Results support independent additive contributions of both physiological stress processes and early life parental stressors in the development of internalizing symptoms in middle childhood. Future investigation is needed to better understand the sensitizing effects of early parental life stress during this developmental stage.
ContributorsLecarie, Emma (Author) / Doane, Leah (Thesis advisor) / Davis, Mary (Committee member) / Grimm, Kevin (Committee member) / Arizona State University (Publisher)
Created2020
Description
Chronic or recurrent pain in childhood is a common and costly health problem, and increases the likelihood of experiencing chronic pain in adulthood. Existing evidence suggests that internalizing symptoms are a risk factor for the development of chronic pain in children and adults. Findings from a small body of research also points to a flattened diurnal cortisol profile, alone and in combination with internalizing symptoms, as a risk factor for future chronic pain among adults. The present study aimed to evaluate whether internalizing, a flattened diurnal cortisol profile, and their combination prospectively predict chronic pain in middle childhood. It was hypothesized that: 1) both internalizing and a flattened diurnal cortisol profile at age 8 would independently predict acquisition of chronic pain at age 9, controlling for age 8 pain; and 2) the combination of high internalizing and a flattened diurnal cortisol rhythm would predict greater risk of increased pain over time. Multilevel models of longitudinal data collected from a sample of 748 twin children revealed that internalizing symptoms and a flattened cortisol slope independently acted as prospective risk factors for increased chronic pain in childhood one year later. However, the interaction between internalizing and diurnal cortisol did not predict future increases in pain. Exploratory analyses evaluating symptoms of overanxiousness demonstrated that the interaction between overanxiousness and a flattened cortisol profile emerged as a marginally significant predictor of future pain. The current findings point to the role of psychological and physiological risk factors for the development of chronic pediatric pain, and may help to identify early targets for prevention efforts.
ContributorsEltze, Lara Malin (Author) / Davis, Mary (Thesis director) / Doane, Leah (Committee member) / School of International Letters and Cultures (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12