Matching Items (4)
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- All Subjects: Animal behavior
- Genre: Academic theses
- Creators: Bimonte-Nelson, Heather A.
- Resource Type: Text
- Status: Published
Description
There are several visual dimensions of food that can affect food intake, example portion size, color, and variety. This dissertation elucidates the effect of number of pieces of food on preference and amount of food consumed in humans and motivation for food in animals. Chapter 2 Experiment 1 showed that rats preferred and also ran faster for multiple pieces (30, 10 mg pellets) than an equicaloric, single piece of food (300 mg) showing that multiple pieces of food are more rewarding than a single piece. Chapter 2 Experiment 2 showed that rats preferred a 30-pellet food portion clustered together rather than scattered. Preference and motivation for clustered food pieces may be interpreted based on the optimal foraging theory that animals prefer foods that can maximize energy gain and minimize the risk of predation. Chapter 3 Experiment 1 showed that college students preferred and ate less of a multiple-piece than a single-piece portion and also ate less in a test meal following the multiple-piece than single-piece portion. Chapter 3 Experiment 2 replicated the results in Experiment 1 and used a bagel instead of chicken. Chapter 4 showed that college students given a five-piece chicken portion scattered on a plate ate less in a meal and in a subsequent test meal than those given the same portion clustered together. This is consistent with the hypothesis that multiple pieces of food may appear like more food because they take up a larger surface area than a single-piece portion. All together, these studies show that number and surface area occupied by food pieces are important visual cues determining food choice in animals and both food choice and intake in humans.
ContributorsBajaj, Devina (Author) / Phillips, Elizabeth D. (Thesis advisor) / Cohen, Adam (Committee member) / Johnston, Carol (Committee member) / Bimonte-Nelson, Heather A. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Ethinyl estradiol, (EE) a synthetic, orally bio-available estrogen, is the most commonly prescribed form of estrogen in oral contraceptives (Shively, C., 1998), and is found in at least 30 different contraceptive formulations currently prescribed to women (Curtis et al., 2005). EE is also used in hormone therapies prescribed to menopausal women, such as FemhrtTM (Simon et al., 2003). Thus, EE is prescribed clinically to women at ages ranging from puberty through reproductive senescence. Here, in two separate studies, the cognitive effects of cyclic or tonic EE administration following ovariectomy (Ovx) were evaluated in young, female rats. Study I assessed the cognitive effects of low and high doses of EE, delivered tonically via a subcutaneous osmotic pump. Study II evaluated the cognitive effects of low, medium, and high doses of EE administered via a daily subcutaneous injection. For these studies, the low and medium doses correspond to the range of doses currently used in clinical formulations, and the high dose corresponds to the range of doses prescribed to a generation of women between 1960 and 1970, when oral contraceptives first became available. For each study, cognition was evaluated with a battery of maze tasks tapping several domains of spatial learning and memory. At the highest dose, EE treatment impaired multiple domains of spatial memory relative to vehicle treatment, regardless of administration method. When given cyclically at the low and medium doses, EE did not impact working memory, but transiently impaired reference memory during the learning phase of testing. Of the doses and regimens tested here, only EE at the highest dose impaired several domains of memory; this was seen for both cyclic and tonic regimens. Cyclic and tonic delivery of low EE, a dose that corresponds to doses used in the clinic today, resulted in transient and null impairments, respectively, on cognition.
ContributorsMennenga, Sarah E (Author) / Bimonte-Nelson, Heather A. (Thesis advisor) / Baxter, Leslie C. (Committee member) / Olive, Michael F. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Women are exposed to numerous endogenous and exogenous hormones across the lifespan. In the last several decades, the prescription of novel hormonal contraceptives and hormone therapies (HTs) have resulted in aging women that have a unique hormone exposure history; little is known about the impact of these hormone exposures on short- and long- term brain health. The goal of my dissertation was to understand how lifetime hormone exposures shape the female cognitive phenotype using several innovative approaches, including a new human spatial working memory task, the human radial arm maze (HRAM), and several rodent menopause models with variants of clinically used hormone treatments. Using the HRAM (chapter 2) and established human neuropsychological tests, I determined males outperformed females with high endogenous or exogenous estrogen levels on visuospatial tasks and the spatial working memory HRAM (chapter 3). Evaluating the synthetic estrogen in contraceptives, ethinyl estradiol (EE), I found a high EE dose impaired spatial working memory in ovariectomized (Ovx) rats, medium and high EE doses reduced choline-acetyltransferace-immunoreactive neuron population estimates in the basal forebrain following Ovx (chapter 4), and low EE impaired spatial cognition in ovary-intact rats (chapter 5). Assessing the impact of several clinically-used HTs, I identified a window of opportunity around ovarian follicular depletion outside of which the HT conjugated equine estrogens (CEE) was detrimental to spatial memory (chapter 6), as well as therapeutic potentials for synthetic contraceptive hormones (chapter 9) and bioidentical estradiol (chapter 7) during and after the transition to menopause. Chapter 6 and 7 findings, that estradiol and Ovx benefitted cognition after the menopause transition, but CEE did not, are perhaps due to the negative impact of ovarian-produced, androstenedione-derived estrone; indeed, blocking androstenedione’s conversion to estrone prevented its cognitive impairments (chapter 8). Finally, I determined that EE combined with the popular progestin levonorgestrel benefited spatial memory during the transition to menopause, a profile not seen with estradiol, levonorgestrel, or EE alone (chapter 9). This work identifies several cognitively safe, and enhancing, hormonal treatment options at different time points throughout female aging, revealing promising avenues toward optimizing female health.
ContributorsMennenga, Sarah E (Author) / Bimonte-Nelson, Heather A. (Thesis advisor) / Aiken, Leona (Committee member) / Whiteaker, Paul (Committee member) / Talboom, Joshua (Committee member) / Arizona State University (Publisher)
Created2015
Description
How a colony regulates the division of labor to forage for nutritional resources while accommodating for changes in colony demography is a fundamental question in the sociobiology of social insects. In honey bee, Apis mellifera, brood composition impacts the division of labor, but it is unknown if colonies adjust the allocation of foragers to carbohydrate and protein resources based on changes in the age demography of larvae and the pheromones they produce. Young and old larvae produce pheromones that differ in composition and volatility. In turn, nurses differentially provision larvae, feeding developing young worker larvae a surplus diet that is more queen-like in protein composition and food availability, while old larvae receive a diet that mimics the sugar composition of the queen larval diet but is restrictively fed instead of provided ad lib. This research investigated how larval age and the larval pheromone e-β ocimene (eβ) impact foraging activity and foraging load. Additional cage studies were conducted to determine if eβ interacts synergistically with queen mandibular pheromone (QMP) to suppress ovary activation and prime worker physiology for nursing behavior. Lastly, the priming effects of larval age and eβ on worker physiology and the transition from in-hive nursing tasks to outside foraging were examined. Results indicate that workers differentially respond to larvae of different ages, likely by detecting changes in the composition of the pheromones they emit. This resulted in adjustments to the foraging division of labor (pollen vs. nectar) to ensure that the nutritional needs of the colony's brood were met. For younger larvae and eβ, this resulted in a bias favoring pollen collection. The cage studies reveal that both eβ and QMP suppressed ovary activation, but the larval pheromone was more effective. Maturing in an environment of young or old larvae primed bees for nursing and impacted important endocrine titers involved in the transition to foraging, so bees maturing in the presence of larvae foraged earlier than control bees reared with no brood.
ContributorsTraynor, Kirsten S. (Author) / Page, Robert E. (Thesis advisor) / Hölldobler, Berthold (Committee member) / Pratt, Stephen (Committee member) / Liebig, Jürgen (Committee member) / Brent, Colin (Committee member) / Baluch, Page (Committee member) / Arizona State University (Publisher)
Created2014