Matching Items (6)
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- All Subjects: Alzheimer's Disease
- All Subjects: Brains
- Creators: Bimonte-Nelson, Heather
- Status: Published
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
With no known cure, Alzheimer's disease (AD) is the most common dementia, affecting more than 5.5 million Americans. Research has shown that women who undergo surgical menopause (i.e. removal of the ovaries) before the onset of natural menopause are at a greater risk for AD. It is hypothesized that this greater relative risk of developing AD is linked to ovarian hormone deprivation associated with surgical menopause. The purpose of these studies was to evaluate the behavioral changes that occur after a short-term (ST) and a long-term (LT) ovarian hormone deprivation in a mouse model of AD. Wildtype (Wt) or APP/PS1 (Tg) mutation mice underwent either a sham surgery or an ovariectomy (Ovx) surgery at three months of age. Study 1 consisted of a short-term cohort that was behaviorally tested one month following surgery on a battery of spatial memory tasks including, the Morris water maze, delayed matched-to-sample water maze, and visible platform task. Study 2 consisted of a long-term cohort that was behaviorally tested on the same cognitive battery three months following surgery. Results of Study 1 revealed that genotype interacted with surgical menopause status, such that after a short-term ovarian hormone deprivation, Ovx induced a genotype effect while Sham surgery did not. Results of Study 2 showed a similar pattern of effects, with a comparable interaction between genotypes and surgical menopause status. These findings indicate that the cognitive impact of ovarian hormone deprivation depends on AD-related genotype. Neuropathology evaluations in these mice will be done in the near future and will allow us to test relations between surgical menopause status, cognition, and AD-like neuropathology.
ContributorsPalmer, Justin M. (Author) / Bimonte-Nelson, Heather (Thesis director) / Oddo, Salvatore (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Alzheimer’s disease (AD) is an irreversible brain disorder that plagues millions of people with no current cure. Current clinical research is slowly advancing to more definitive treatments in hopes of reducing the effects of progressive cognitive and behavioral decline, but none so far can slow AD’s onset. A brain area known as the nucleus incertus (NI) was recently discovered to potentially impact AD because of its connections to brain targets that degenerate; however, the NI’s role is unknown. This goal of this experiment was to use a transgenic mouse model (APP/PS1) that expresses AD pathology slowly as found in humans, and to test the mice in a variety of cognitive and anxiety assessments. Mice of both sexes and two different ages were used, with the first being young adult before AD pathology manifests (around 3-4 months old), and the second being around the cusp of when AD pathology manifests (late adult, 8-10 months old). The mice were tested in a variety of cognitive tasks that included the novel object recognition (NOR), Morris water maze (MWM), and the object placement (OP), with the latter being the focus of my thesis. Anxiety measures were taken from the open field (OF) and elevated plus maze (EPM) with the visible platform (VP) used to ensure mice could perform on the rigorous MWM task. In the OP, we found an age effect, where the older mice were less likely to explore the moved object during the OP compared to the younger mice; motor ability was unlikely to explain this effect. We did not find any significant age by genotype effects. These findings indicate that cognitive impairment only just started to affect the older cohort, since OP impairment was found on one measure and not another. Other measures currently being quantified will be helpful in understanding this data, and to see whether learning, memory, and anxiety are affected.
ContributorsDapon, Bianca (Author) / Conrad, Cheryl (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2023-05
Description
There are currently no disease-modifying treatments to halt or attenuate the progression of Alzheimer’s disease (AD). Transgenic rodent models have provided researchers the ability to recapitulate particular pathological and symptomological events in disease progression. Complete reproduction of all features of AD in a rodent model has not been achieved, potentially lending to the inconclusive treatment results at the clinical level. Recently, the TgF344-AD transgenic rat model has started to be evaluated; however, it has not been well characterized in terms of its cognition, which is fundamental to understanding the trajectory of aging relative to pathology and learning and memory changes. Therefore, the aim of the current study was to identify cognitive outcomes at 6, 9, and 12 months of age in the TgF344-AD rat model. Sixty female transgenic (Tg) and wildtype (WT) rats were tested on the water radial arm maze, Morris water maze, and visible platform task to evaluate cognition. Results from the asymptotic phase of the water radial arm maze showed that the 6 mo-Tg animals had marginally impaired working memory compared to 6 mo-WT rats, and 12 mo-Tg rats had significantly impaired working memory compared to 12 mo-WT rats. The 9 mo-Tg animals did not demonstrate a significant difference in working memory errors compared to the 9 mo-WT animals. This pattern of impairment, wherein Tg animals made more working memory errors compared to WT animals at the 6 and 12 month time points, but not at the 9 month time point, may be indicative of an inflammatory response that proves helpful at incipient stages of disease progression but eventually leads to further cognitive impairment. These results provide insight into the potential earliest time point that prodromal cognitive symptoms of AD exist, and how they progress with aging. Brain tissue was collected at sacrifice for future analyses of pathology, which will be used to glean insight into the temporal progression of pathological and cognitive outcomes.
ContributorsBulen, Haidyn Leigh (Co-author) / Bulen, Haidyn (Co-author) / Bimonte-Nelson, Heather (Thesis director) / Presson, Clark (Committee member) / Conrad, Cheryl (Committee member) / Woner, Victoria (Committee member) / Peña, Veronica (Committee member) / School of International Letters and Cultures (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05