Matching Items (5)
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- Creators: Department of Psychology
- Creators: Rahman, Qasim
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
There is preclinical evidence that the detrimental cognitive effects of hormone loss can be ameliorated by estrogen therapy (Bimonte, Acosta, & Talboom, 2010), however, one of the primary concerns with current hormone therapies is that they are nonselective, leading to increased risk of breast and endometrial cancers as well as heart disease. Thus, in order to achieve a successful and clinically relevant long-term hormone therapy option, it is optimal to find an estrogen therapy regimen that is selective to its target tissue. Recently, phytoestrogens have been found to exert selective, beneficial effects on cognition and brain. For example, genistein and diadzein produce neuroprotective effects in cognitive brain regions (Zhao, Chen, & Diaz Brinton, 2002). The purpose of this study was threefold: 1) to examine the cognitive impact of phytoestrogens in young ovariectomized rats, 2) to replicate the dose effects found in the Luine study (Luine et al., 2006), while controlling for manufacturer differences, and 3) to assess if the rodent diet used in our laboratory has an estrogenic-like cognitive impact.The current findings suggest that, at least for object memory, diets containing varying amounts of phytoestrogens can alter cognition, with diets containing high amounts of phytoestrogens showing potential benefits to this type of memory.
ContributorsWhitton, Elizabeth Nicole (Author) / Bimonte-Nelson, Heather (Thesis director) / Presson, Clark (Committee member) / Baxter, Leslie (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2013-05
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
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
Recent work in free-recall tasks suggest that human memory foraging may follow a Lévy flight distribution – a random walk procedure that is common in other activities of cognitive agents, such as animal and human food foraging. This study attempts to draw parallels between memory search and physical search, with the assumption that humans follow similar search patterns in both. To date, research merely equates the two processes (foraging in memory and the physical world) based on a similarity in statistical structure. This study starts with demonstrating a relationship between physical distance traveled and IRIs by having participants list countries. An IRI, inter-retrieval interval, is the time interval between items recalled. The next experiment uses multidimensional scaling (MDS) to derive a Euclidean perceptual space from similarity ratings of freely-recalled items and then maps the trajectory of human thought through this perceptual space. This trajectory can offer a much more compelling comparison to physical foraging behavior. Finally, a possible correlate of Lévy flight foraging is explored called critical slowing down. Statistically significant evidence was found in all three experiments. The discussion connects all three experiments and what their results mean for human memory foraging.
ContributorsGreer, Katharine Marie (Author) / Amazeen, Eric L. (Thesis director) / Glenberg, Arthur (Committee member) / Amazeen, Polemnia (Committee member) / Department of Psychology (Contributor) / School of Criminology and Criminal Justice (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Research on joint control during arm movements in adults has led to the development of the Leading Joint Hypothesis (LJH), which states that the central nervous system takes advantage of interaction torque (IT) and muscle torque (MT) to produce movements with maximum efficiency in the multi-jointed limbs of the human body. A gap in knowledge exists in determining how this mature pattern of joint control develops in children. Prior research focused on the kinematics of joint control for children below the age of three; however, not much is known about interjoint coordination with respect to MT and IT in school-aged children. In the present study, joint control at the shoulder, elbow, and wrist during drawing of five shapes was investigated. A random sample of nine typically developing children ages 6 to 12 served as subjects. The task was to trace with the index finger a template placed on a horizontal table. The template consisted of a circle, horizontal, vertical, right-diagonal, and left-diagonal line. Analysis of muscle torque contribution (MTC) revealed the individual roles of MT and IT in the shoulder, elbow, and wrist joints. During drawing of the horizontal line, which requires the most difficult joint control pattern in adults because it does not allow the use of IT for joint rotation, joint control was found to change through development. For the youngest children, the function of elbow MT modified to suppress IT, thereby producing large elbow rotation. The oldest children simplified this by using the shoulder as the principal joint of movement production and with decreased assistance from the elbow. For the other four drawing movements, differences in the pattern of joint control used by all of the subjects was unaffected by an increase in age. Overall, the results suggest that in children above 6 years of age, minor changes in joint control occur during drawing of relatively simple movements. The limited effect of age that was observed could be related to the restriction of movements to the horizontal plane. For a future study, three-dimensional movements that provide more freedom in joint control due to redundancy of degrees of freedom could be more informative about developmental changes in joint coordination.
ContributorsKemmou, Nadaa (Co-author) / Way, Victoria (Co-author) / Dounskaia, Natalia (Thesis director) / Vidt, Meghan (Committee member) / School of Nutrition and Health Promotion (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12