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Urbanization exposes wildlife to many unfamiliar environmental conditions, including the presence of novel structures and food sources. Adapting to or thriving within such anthropogenic modifications may involve cognitive skills, whereby animals come to solve novel problems while navigating, foraging, etc. The increased presence of humans in urban areas is an

Urbanization exposes wildlife to many unfamiliar environmental conditions, including the presence of novel structures and food sources. Adapting to or thriving within such anthropogenic modifications may involve cognitive skills, whereby animals come to solve novel problems while navigating, foraging, etc. The increased presence of humans in urban areas is an additional environmental challenge that may potentially impact cognitive performance in wildlife. To date, there has been little experimental investigation into how human disturbance affects problem solving in animals from urban and rural areas. Urban animals may show superior cognitive performance in the face of human disturbance, due to familiarity with benign human presence, or rural animals may show greater cognitive performance in response to the heightened stress of unfamiliar human presence. Here, I studied the relationship between human disturbance, urbanization, and the ability to solve a novel foraging problem in wild-caught juvenile house finches (Haemorhous mexicanus). This songbird is a successful urban dweller and native to the deserts of the southwestern United States. In captivity, finches captured from both urban and rural populations were presented with a novel foraging task (sliding a lid covering their typical food dish) and then exposed to regular periods of high or low human disturbance over several weeks before they were again presented with the task. I found that rural birds exposed to frequent human disturbance showed reduced task performance compared to human-disturbed urban finches. This result is consistent with the hypothesis that acclimation to human presence protects urban birds from reduced cognition, unlike rural birds. Some behaviors related to solving the problem (e.g. pecking at and eying the dish) also differed between urban and rural finches, possibly indicating that urban birds were less neophobic and more exploratory than rural ones. However, these results were unclear. Overall, these findings suggest that urbanization and acclimation to human presence can strongly predict avian response to novelty and cognitive challenges.
ContributorsCook, Meghan Olivia (Author) / McGraw, Kevin (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Weaver, Melinda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
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Description
Following natural menopause, androstenedione becomes the main hormone secreted by the follicle-depleted ovaries. We have previously evaluated high physiological doses of androstenedione in the female rodent, and found relations between higher androstenedione levels and spatial memory impairment; this relationship was shown when androstenedione levels were of endogenous, or exogenous, origin

Following natural menopause, androstenedione becomes the main hormone secreted by the follicle-depleted ovaries. We have previously evaluated high physiological doses of androstenedione in the female rodent, and found relations between higher androstenedione levels and spatial memory impairment; this relationship was shown when androstenedione levels were of endogenous, or exogenous, origin (Acosta et al., 2009, Camp et al., 2012). This androstenedione-induced memory impairment in females led us to question whether this androgen also impairs memory in males; no study has yet evaluated androstenedione's impact on cognition in the male rodent model. This is a clinically relevant question, as androstenedione is a steroid of abuse. In the current study, four-month old male rats were given either a daily injection of androstenedione, androstenedione with anastrozole or vehicle (polyethylene glycol). Subjects completed a battery of cognitive tasks evaluating spatial working, reference, and recent memory including the water radial arm maze (WRAM), Morris water maze (MM), and delayed match-to-sample maze (DMTS). We found that androstenedione administration impaired spatial cognitive performance in MM on early overnight forgetting and DMTS early recent memory trials across all days of testing. In addition, we found that androstenedione with anastrozole administration impaired spatial cognitive performance in the learning phases and early overnight forgetting in the MM but had no impact in DMTS testing. There were no significant differences in the WRAM maze for either group. Our findings suggest that androstenedione can impair spatial reference and early recent memory, and that anastrozole reverses this impairment for early recent memory, but not reference memory. Interpreted in the context of hormone conversion, androstenedione's effects on spatial learning and memory may be due, in part, to its conversion to estrone.
ContributorsTorres, Laura Maria (Co-author) / Camp, Bryan (Co-author) / Karber, Lily (Co-author) / Hiroi, Ryoko (Co-author, Committee member) / Bimonte-Nelson, Heather (Co-author, Thesis director) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2014-05
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Description
Human perceptual dimensions of sound are not necessarily simple representations of the actual physical dimensions that make up sensory input. In particular, research on the perception of interactions between acoustic frequency and intensity has shown that people exhibit a bias to expect the perception of pitch and loudness to change

Human perceptual dimensions of sound are not necessarily simple representations of the actual physical dimensions that make up sensory input. In particular, research on the perception of interactions between acoustic frequency and intensity has shown that people exhibit a bias to expect the perception of pitch and loudness to change together. Researchers have proposed that this perceptual bias occurs because sound sources tend to follow a natural regularity of a correlation between changes in intensity and frequency of sound. They postulate that the auditory system has adapted to expect this naturally occurring relationship to facilitate auditory scene analysis, the tracking and parsing sources of sound as listeners analyze their auditory environments. However, this correlation has only been tested with human speech and musical sounds. The current study explores if animal sounds also exhibit the same natural correlation between intensity and frequency and tests if people exhibit a perceptual bias to assume this correlation when listening to animal calls. Our principal hypotheses are that animal sounds will tend to exhibit a positive correlation between intensity and frequency and that, when hearing such sounds change in intensity, listeners will perceive them to also change in frequency and vice versa. Our tests with 21 animal calls and 8 control stimuli along with our experiment with participants responding to these stimuli supported these hypotheses. This research provides a further example of coupling of perceptual biases with natural regularities in the auditory domain, and provides a framework for understanding perceptual biases as functional adaptations that help perceivers more accurately anticipate and utilize reliable natural patterns to enhance scene analyses in real world environments.
ContributorsWilkinson, Zachary David (Author) / McBeath, Michael (Thesis director) / Glenberg, Arthur (Committee member) / Rutowski, Ronald (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2014-05
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Description
Menopause is reproductive senescence characterized by a loss of ovarian estrogen and progesterone. Women can experience cognitive decline and other negative symptoms with the loss of ovarian hormones (Sherwin, 2006). While hormone therapies (HT) can treat symptoms of menopause and may have neuroprotective properties, such as the potential to decrease

Menopause is reproductive senescence characterized by a loss of ovarian estrogen and progesterone. Women can experience cognitive decline and other negative symptoms with the loss of ovarian hormones (Sherwin, 2006). While hormone therapies (HT) can treat symptoms of menopause and may have neuroprotective properties, such as the potential to decrease the risk of Alzheimer's Disease (Behl & Manthey, 2000), there are many effects of current HTs that are not ideal. Indeed, optimizing conventional HTs has proven complex, indicating a need for alternative therapies. Phytoestrogens are estrogenic compounds found naturally in plants such as soybeans, that could provide new treatment options. Dietary phytoestrogens can benefit memory in the rodent model (Luine, 2006), although the mechanism underlying these effects is unclear. Basal forebrain cholinergic projections have been shown to mediate the cognitive benefits of estrogen (Gibbs, 2010); we hypothesize that phytoestrogens act similarly, via the cholinergic system, to impact memory. We administered varying doses of phytoestrogen-containing diets to ovariectomized female rats, and used the place recognition task to evaluate spatial memory. Brains were then analyzed for choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine, in the vertical-diagonal bands (VDB) and the medial septum (MS) of the basal forebrain. Results showed that ChAT cell counts in the VDB were marginally higher with dietary phytoestrogen treatment. Further, VDB ChAT cell counts positively correlated with place recognition performance, indicating that animals with more VDB ChAT neurons exhibited better spatial memory performance. These results suggest that phytoestrogens might act similarly to natural, endogenously circulating estrogens, and identify phytoestrogens as a direction for investigation as a HT.
ContributorsMousa, Abeer Abdul (Author) / Bimonte-Nelson, Heather (Thesis director) / Olive, Foster (Committee member) / Deviche, Pierre (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / W. P. Carey School of Business (Contributor) / School of Life Sciences (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2014-05
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Description
Drospirenone (DRSP) is a novel, pharmacologically unique synthetic progestin with properties more similar to the endogenous progestogen, progesterone, than any other progestin currently on the market. While a significant amount of research has been conducted on the risks associated with DRSP, the impact of DRSP on cognition, especially in reference

Drospirenone (DRSP) is a novel, pharmacologically unique synthetic progestin with properties more similar to the endogenous progestogen, progesterone, than any other progestin currently on the market. While a significant amount of research has been conducted on the risks associated with DRSP, the impact of DRSP on cognition, especially in reference to learning and memory, is not well understood. However, it is imperative to fully understand the cognitive effects of DRSP, both alone and in combination with EE (as taken in a combined oral contraceptive [COC]), so that women and their physicians can make a fully-informed decision when deciding to take a DRSP-containing COC. Study 1 examined the effects of three doses of DRSP in order to determine the optimal dose for combining with EE, and found that the medium dose of DRSP (30 µg/day) enhanced spatial working memory performance. In Study 2, the medium dose of DRSP from Study 1 was combined with low (0.125 µg/day) and high (0.3 µg/day) doses of EE to examine the effects of DRSP as taken with EE in a COC. The results from Study 2 indicated that when DRSP was combined with a low, but not high, dose of EE, spatial working memory impairments were seen at the highest working memory load. Anxiety-like behavior was evaluated using the OFT, and DRSP was shown to decrease measures of anxiety-like behavior. Additionally, while treatment with a high dose of EE decreased several measures of anxiety-like behavior, a low dose of EE did not, suggestive of a dose response. Taken together, the findings presented from both studies suggest that some of the cognitive effects of the combination of DRSP with EE are different than those of either hormone administered on its own. Further exploration in a preclinical, ovary-intact animal model is a next step to fully understand these effects in the translational context of a contraceptive, given that women taking an EE-DRSP combination are typically ovary-intact.
ContributorsPoisson, Mallori Louise (Author) / Bimonte-Nelson, Heather (Thesis director) / Doane, Leah (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Description
The aim of this study was to determine whether IUD administration, with and without the presence of Levo, and with and without the presence of the ovaries, impacts cognition in a rat model. Rats received either Sham or Ovariectomy (Ovx) surgery (removal of the ovaries), plus either no IUD, a

The aim of this study was to determine whether IUD administration, with and without the presence of Levo, and with and without the presence of the ovaries, impacts cognition in a rat model. Rats received either Sham or Ovariectomy (Ovx) surgery (removal of the ovaries), plus either no IUD, a Blank IUD (without Levo), or a Levo-releasing IUD (Levo IUD), enabling us to evaluate the effects of Ovx and the effects of IUD administration on cognition. Two weeks after surgery, all treatment groups were tested on the water radial arm maze, Morris water maze, and visible platform task to evaluate cognition. At sacrifice, upon investigation of the uteri, it was determined that some of the IUDs were no longer present in animals from these groups: Sham\u2014Blank IUD, Ovx\u2014Blank IUD, and Sham\u2014Levo IUD. Results from the remaining three groups showed that compared to Sham animals with no IUDs, Ovx animals with no IUDs had marginally impaired working memory performance, and that Ovx animals with Levo IUDs as compared to Ovx animals with no IUDs had marginally enhanced memory performance, not specific to a particular memory type. Results also showed that Ovx animals with Levo IUDs had qualitatively more cells in their vaginal smears and increased uterine horn weight compared to Ovx animals with no IUDs, suggesting local stimulation of the Levo IUDs to the uterine horns. Overall, these results provide alternative evidence to the hypothesis that the Levo IUD administers Levo in solely a localized manner, and suggests that the possibility for the Levo IUD to affect reproductive cyclicity in ovary-intact animals is not rejected. The potential for the Levo IUD to exert effects on cognition suggests that either the hormone does in fact systemically circulate, or that the Levo IUD administration affects cognition by altering an as yet undetermined hormonal or other feedback between the uterus and the brain.
ContributorsStrouse, Isabel Martha (Author) / Bimonte-Nelson, Heather (Thesis director) / Glenberg, Arthur (Committee member) / Sirianni, Rachael (Committee member) / Conrad, Cheryl (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Description
Estradiol (E2) and Levonorgestrel (Levo) are two hormones commonly used in hormone therapy (HT) to decrease symptoms associated with menopause. Both of these hormones have been shown to have beneficial effects on cognition when given alone in a rodent model of menopause. However, it is unknown whether these hormones, when

Estradiol (E2) and Levonorgestrel (Levo) are two hormones commonly used in hormone therapy (HT) to decrease symptoms associated with menopause. Both of these hormones have been shown to have beneficial effects on cognition when given alone in a rodent model of menopause. However, it is unknown whether these hormones, when taken in combination, are beneficial or harmful to cognition. This is a critically important question given that these hormones are most often given in combination versus separately. This thesis is composed of two studies examining the cognitive effects of E2 and Levo using a rat model of surgical menopause. Study 1 assessed how the dose of E2 treatment in rats impacted cognitive performance, and found that low dose E2 enhanced working memory performance. Next, based on the results from Study 1, Study 2 used low dose E2 in combination with different doses of Levo to examine the cognitive effects of several E2 to Levo ratio combinations. The results from Study 2 demonstrated that the combination of low dose E2 with a high dose of Levo at a 1:2 ratio impaired cognition, and that the ratio currently used in HT, 3:1, may also negatively impact cognition. Indeed, there was a dose response effect indicating that working and reference memory performance was incrementally impaired as Levo dose increased. The findings in this thesis suggest that the E2 plus Levo combination is likely not neutral for cognitive function, and prompts further evaluation in menopausal women, as well as drug discovery research to optimize HT using highly controlled preclinical models.
ContributorsBerns-Leone, Claire Elizabeth (Co-author) / Prakapenka, Alesia (Co-author) / Pena, Veronica (Co-author) / Northup-Smith, Steven (Co-author) / Melikian, Ryan (Co-author) / Ladwig, Ducileia (Co-author) / Patel, Shruti (Co-author) / Croft, Corissa (Co-author) / Bimonte-Nelson, Heather (Thesis director) / Glenberg, Arthur (Committee member) / Conrad, Cheryl (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description
Variability is inherent in human movement, and poses a challenge to researchers attempting to measure balance. Human movement variability was analyzed using two methods: standard deviation and largest Lyapunov exponent. The experiment was a sit-to-stand task with physical and cognitive perturbations. The physical perturbation consisted of stable and unstable platform

Variability is inherent in human movement, and poses a challenge to researchers attempting to measure balance. Human movement variability was analyzed using two methods: standard deviation and largest Lyapunov exponent. The experiment was a sit-to-stand task with physical and cognitive perturbations. The physical perturbation consisted of stable and unstable platform conditions, while the cognitive perturbation consisted of a counting task. The data were collected from 24 healthy young adults. The purpose of this study was to compare the standard deviation and largest Lyapunov exponent as measures of stability, and to determine the Lyapunov exponent's sensitivity to cognitive perturbation. Evidence suggests that the Lyapunov exponent serves as a more accurate indicator of stability than standard deviation, and that it lacks sensitivity to the counting task.
ContributorsJohnson, Jennifer Jeanne (Author) / Amazeen, Polemnia (Thesis director) / Amazeen, Eric (Committee member) / Stone, Gregory (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description

In females, critical hormonal shifts occur during puberty, menstruation, pregnancy, and <br/>menopause. The fluctuating ovarian hormone levels across a woman’s lifespan likely contribute <br/>to inflammatory responses driven by the immune system, which is regulated by a variety of <br/>physiological pathways and microbiological cues. Pregnancy in particular results in drastic <br/>changes

In females, critical hormonal shifts occur during puberty, menstruation, pregnancy, and <br/>menopause. The fluctuating ovarian hormone levels across a woman’s lifespan likely contribute <br/>to inflammatory responses driven by the immune system, which is regulated by a variety of <br/>physiological pathways and microbiological cues. Pregnancy in particular results in drastic <br/>changes in circulating hormone profiles, and involves a variety of physiological changes, <br/>including inflammatory responses of the immune system. There is evidence that these effects are <br/>mediated, in part, by the significant hormone fluctuations that characterize pregnancy and <br/>postpartum periods. This thesis highlights and synthesizes important physiological changes <br/>associated with pregnancy, and their potential implications on cognitive and brain aging in <br/>women. A tertiary model of cognition is presented depicting interactions between hormonal <br/>history, reproductive history, and immune functions. This research is important to create a better <br/>understanding of women’s health and enhance medical care for women throughout pregnancy <br/>and across reproductive hormone shifts across the lifespan.

ContributorsLogan-Robledo, Santiago Rodrigo (Author) / Bimonte-Nelson, Heather A. (Thesis director) / Koebele, Stephanie V. (Committee member) / Simard, Alain (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

The relevance of depression in the clinical realm is well known, as it is one of the most common mental disorders in the United States. Clinical depression is the leading cause of disease for women worldwide. The sex difference in depression and anxiety has guided the research of not just

The relevance of depression in the clinical realm is well known, as it is one of the most common mental disorders in the United States. Clinical depression is the leading cause of disease for women worldwide. The sex difference in depression and anxiety has guided the research of not just recent studies but older studies as well, supporting the theory that gonadal hormones are associated with the mechanisms of emotional cognition. The scientific literature points towards a clear correlative relationship between gonadal hormones, especially estrogens, and emotion regulation. This thesis investigates the neural pathways that have been indicated to regulate mood and anxiety. Currently, the research points to the hypothalamic-pituitary-adrenal axis, which regulates the stress response through its ultimate secretion of cortisol through the adrenal cortex, and its modulated response when exposed to higher levels of estrogen. Another mechanism that has been investigated is the interaction of estrogen and the serotonergic system, which is noteworthy because the serotonergic system is known for its importance in mood regulation. However, it is important to note that the research seeking to determine the neurobiological underpinnings of estrogen and the serotonergic system is not expansive. Future research should focus on determining the direct relationship between cortisol hypersecretion and estrogens, the specific neurobiological effects of serotonergic receptor subtypes on the antidepressant actions of estrogens, and the simultaneous effects of the stress and serotonergic systems on depressive symptoms.

ContributorsArroyo, Mariana (Author) / Bimonte-Nelson, Heather (Thesis director) / Jurutka, Peter (Committee member) / School of International Letters and Cultures (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05