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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
Cultural beliefs and behaviors can serve as both risk and protective processes for Latino adolescents, with some recent empirical work suggesting the important protective role of bicultural values (e.g., endorsing high levels of both mainstream culture and culture of origin). We expanded on past research to explore whether bicultural values were associated with internalizing (depressive, anxiety, stress) symptoms and externalizing (alcohol use) symptoms among a sample of Latino adolescents preparing to begin college. We hypothesized biculturalism to protect against all negative outcomes. Our sample consisted of 209 college-bound Latino adolescents (65% female; 85.1% Mexican descent; 10.6% 1st generation, 62% 2nd generation) who were enrolled in university for the coming fall. All multivariate models included sex, ethnicity, parent education, and immigrant generation status as covariates. Correlations and multivariate analyses revealed that higher bicultural values were associated with lower depressive symptoms, lower anxiety symptoms, lower stress, and greater alcohol use. Gender was shown to moderate the relationship between biculturalism and alcohol use. Overall, findings suggested that greater bicultural values were associated with lower endorsement of internalizing symptoms for all participants, but higher endorsement of alcohol use over the last year for the highly bicultural females. Biculturalism may be particularly protective for Latino adolescents who are preparing to attend college given the need for them to transition into an environment with high acculturative demands. However, our results also highlight that these bicultural females may be at greater risk for alcohol use and related problems.
ContributorsDilgert, Janice (Author) / Doane, Leah (Thesis director) / Thompson, Daisy (Committee member) / Department of Psychology (Contributor) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
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
The COVID-19 pandemic has generated alarming increases in psychological distress and alcohol use behaviors and has caused the greatest increases in depression and anxiety symptoms among college students. Prior studies have examined the impact of COVID-19 broadly on mental health and alcohol use outcomes; however, few studies have examined these impacts in college students. Previous studies have examined individual factors that could moderate the relation between COVID-19 related stressors and mental health and alcohol use outcomes, but knowledge is lacking regarding the role of emotion regulation. The present study aimed to examine the role of emotion regulation in the relation between both COVID-19 stressful experiences and COVID-19 related worry and mental health and alcohol use outcomes, and to explore racial/ethnic differences in their associations. Four hierarchical multiple regression models were conducted to assess main effects of COVID-19 stressors and emotion regulation, as well as moderation of the effect of emotion regulation on depression symptoms, anxiety symptoms, alcohol consumption, and alcohol use disorder (AUD) symptoms during the past year. COVID-19 related worry was associated with greater symptoms of both mental health outcomes, whereas COVID-19 related stressful experiences were associated with both mental health outcomes, more alcohol consumption, and more AUD symptoms. Difficulties in emotion regulation had significant main effects on mental health outcomes and AUD symptoms, but not alcohol consumption. Hispanic/Latinx students reported higher experiences of both COVID-19 related stressors, but consumed less alcohol than did White/European students. This study provides further insight into the nature of COVID-19 related stressors and their subsequent impacts. Implications for prevention and intervention on college campuses are discussed.
ContributorsConroy, Isobel (Author) / Su, Jinni (Thesis director) / Corbin, William (Committee member) / Doane, Leah (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of International Letters and Cultures (Contributor)
Created2021-12