Matching Items (994)
Description
The brain is a fundamental target of the stress response that promotes adaptation and survival but the repeated activation of the stress response has the potential alter cognition, emotion, and motivation, key functions of the limbic system. Three structures of the limbic system in particular, the hippocampus, medial prefrontal cortex (mPFC), and amygdala, are of special interest due to documented structural changes and their implication in post-traumatic stress disorder (PTSD). One of many notable chronic stress-induced changes include dendritic arbor restructuring, which reflect plasticity patterns in parallel with the direction of alterations observed in functional imaging studies in PTSD patients. For instance, chronic stress produces dendritic retraction in the hippocampus and mPFC, but dendritic hypertrophy in the amygdala, consistent with functional imaging in patients with PTSD. Some have hypothesized that these limbic region's modifications contribute to one's susceptibility to develop PTSD following a traumatic event. Consequently, we used a familiar chronic stress procedure in a rat model to create a vulnerable brain that might develop traits consistent with PTSD when presented with a challenge. In adult male rats, chronic stress by wire mesh restraint (6h/d/21d) was followed by a variety of behavioral tasks including radial arm water maze (RAWM), fear conditioning and extinction, and fear memory reconsolidation to determine chronic stress effects on behaviors mediated by these limbic structures. In chapter 2, we corroborated past findings that chronic stress caused hippocampal CA3 dendritic retraction. Importantly, we present new findings that CA3 dendritic retraction corresponded with poor spatial memory in the RAWM and that these outcomes reversed after a recovery period. In chapter 3, we also showed that chronic stress impaired mPFC-mediated extinction memory, findings that others have reported. Using carefully assessed behavior, we present new findings that chronic stress impacted nonassociative fear by enhancing contextual fear during extinction that generalized to a new context. Moreover, the generalization behavior corresponded with enhanced functional activation in the hippocampus and amygdala during fear extinction memory retrieval. In chapter 5, we showed for the first time that chronic stress enhanced amygdala functional activation during fear memory retrieval, i.e., reactivation. Moreover, these enhanced fear memories were resistant to protein synthesis interference to disrupt a previously formed memory, called reconsolidation in a novel attempt to weaken chronic stress enhanced traumatic memory. Collectively, these studies demonstrated the plastic and dynamic effects of chronic stress on limbic neurocircuitry implicated in PTSD. We showed that chronic stress created a structural and functional imbalance across the hippocampus, mPFC, and amygdala, which lead to a PTSD-like phenotype with persistent and exaggerated fear following fear conditioning. These behavioral disruptions in conjunction with morphological and functional imaging data reflect a chronic stress-induced imbalance between hippocampal and mPFC regulation in favor of amygdala function overdrive, and supports a novel approach for traumatic memory processing in PTSD.
ContributorsHoffman, Ann (Author) / Conrad, Cheryl D. (Thesis advisor) / Olive, M. Foster (Committee member) / Hammer, Jr., Ronald P. (Committee member) / Sanabria, Federico (Committee member) / Arizona State University (Publisher)
Created2013
Description
Chronic restraint stress impairs hippocampal-mediated spatial learning and memory, which improves following a post-stress recovery period. Here, we investigated whether brain derived neurotrophic factor (BDNF), a protein important for hippocampal function, would alter the recovery from chronic stress-induced spatial memory deficits. Adult male Sprague-Dawley rats were infused into the hippocampus with adeno- associated viral vectors containing the coding sequence for short interfering (si)RNA directed against BDNF or a scrambled sequence (Scr), with both containing the coding information for green fluorescent protein to aid in anatomical localization. Rats were then chronically restrained (wire mesh, 6h/d/21d) and assessed for spatial learning and memory using a radial arm water maze (RAWM) either immediately after stressor cessation (Str-Imm) or following a 21-day post-stress recovery period (Str-Rec). All groups learned the RAWM task similarly, but differed on the memory retention trial. Rats in the Str-Imm group, regardless of viral vector contents, committed more errors in the spatial reference memory domain than did non-stressed controls. Importantly, the typical improvement in spatial memory following recovery from chronic stress was blocked with the siRNA against BDNF, as Str-Rec-siRNA performed worse on the RAWM compared to the non-stressed controls or Str-Rec-Scr. These effects were specific for the reference memory domain as repeated entry errors that reflect spatial working memory were unaffected by stress condition or viral vector contents. These results demonstrate that hippocampal BDNF is necessary for the recovery from stress-induced hippocampal dependent spatial memory deficits in the reference memory domain.
ContributorsOrtiz, J. Bryce (Author) / Conrad, Cheryl D. (Thesis advisor) / Olive, M. Foster (Committee member) / Taylor, Sara (Committee member) / Bimonte-Nelson, Heather A. (Committee member) / Arizona State University (Publisher)
Created2013
Description
This paper considers what factors influence student interest, motivation, and continued engagement. Studies show anticipated extrinsic rewards for activity participation have been shown to reduce intrinsic value for that activity. This might suggest that grade point average (GPA) has a similar effect on academic interests. Further, when incentives such as scholarships, internships, and careers are GPA-oriented, students must adopt performance goals in courses to guarantee success. However, performance goals have not been shown to correlated with continued interest in a topic. Current literature proposes that student involvement in extracurricular activities, focused study groups, and mentored research are crucial to student success. Further, students may express either a fixed or growth mindset, which influences their approach to challenges and opportunities for growth. The purpose of this study was to collect individual cases of students' experiences in college. The interview method was chosen to collect complex information that could not be gathered from standard surveys. To accomplish this, questions were developed based on content areas related to education and motivation theory. The content areas included activities and meaning, motivation, vision, and personal development. The developed interview method relied on broad questions that would be followed by specific "probing" questions. We hypothesize that this would result in participant-led discussions and unique narratives from the participant. Initial findings suggest that some of the questions were effective in eliciting detailed responses, though results were dependent on the interviewer. From the interviews we find that students value their group involvements, leadership opportunities, and relationships with mentors, which parallels results found in other studies.
ContributorsAbrams, Sara (Author) / Hartwell, Lee (Thesis director) / Correa, Kevin (Committee member) / Department of Psychology (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Many factors are at play within the genome of an organism, contributing to much of the diversity and variation across the tree of life. While the genome is generally encoded by four nucleotides, A, C, T, and G, this code can be expanded. One particular mechanism that we examine in this thesis is modification of bases—more specifically, methylation of Adenine (m6A) within the GATC motif of Escherichia coli. These methylated adenines are especially important in a process called methyl-directed mismatch repair (MMR), a pathway responsible for repairing errors in the DNA sequence produced by replication. In this pathway, methylated adenines identify the parent strand and direct the repair proteins to correct the erroneous base in the daughter strand. While the primary role of methylated adenines at GATC sites is to direct the MMR pathway, this methylation has also been found to affect other processes, such as gene expression, the activity of transposable elements, and the timing of DNA replication. However, in the absence of MMR, the ability of these other processes to maintain adenine methylation and its targets is unknown.
To determine if the disruption of the MMR pathway results in the reduced conservation of methylated adenines as well as an increased tolerance for mutations that result in the loss or gain of new GATC sites, we surveyed individual clones isolated from experimentally evolving wild-type and MMR-deficient (mutL- ;conferring an 150x increase in mutation rate) populations of E. coli with whole-genome sequencing. Initial analysis revealed a lack of mutations affecting methylation sites (GATC tetranucleotides) in wild-type clones. However, the inherent low mutation rates conferred by the wild-type background render this result inconclusive, due to a lack of statistical power, and reveal a need for a more direct measure of changes in methylation status. Thus as a first step to comparative methylomics, we benchmarked four different methylation-calling pipelines on three biological replicates of the wildtype progenitor strain for our evolved populations.
While it is understood that these methylated sites play a role in the MMR pathway, it is not fully understood the full extent of their effect on the genome. Thus the goal of this thesis was to better understand the forces which maintain the genome, specifically concerning m6A within the GATC motif.
To determine if the disruption of the MMR pathway results in the reduced conservation of methylated adenines as well as an increased tolerance for mutations that result in the loss or gain of new GATC sites, we surveyed individual clones isolated from experimentally evolving wild-type and MMR-deficient (mutL- ;conferring an 150x increase in mutation rate) populations of E. coli with whole-genome sequencing. Initial analysis revealed a lack of mutations affecting methylation sites (GATC tetranucleotides) in wild-type clones. However, the inherent low mutation rates conferred by the wild-type background render this result inconclusive, due to a lack of statistical power, and reveal a need for a more direct measure of changes in methylation status. Thus as a first step to comparative methylomics, we benchmarked four different methylation-calling pipelines on three biological replicates of the wildtype progenitor strain for our evolved populations.
While it is understood that these methylated sites play a role in the MMR pathway, it is not fully understood the full extent of their effect on the genome. Thus the goal of this thesis was to better understand the forces which maintain the genome, specifically concerning m6A within the GATC motif.
ContributorsBoyer, Gwyneth (Author) / Lynch, Michael (Thesis director) / Behringer, Megan (Committee member) / Geiler-Samerotte, Kerry (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This paper emphasizes how vital prosthetic devices are as tools for both congenital and acquired amputees in order to maximize this population's level of societal productivity, but several issues exist with the current technological focus of development by the prosthetic industry that creates unnecessary hurdles that amputees must surpass in order to truly benefit from these tools. The first major issue is that these devices are not readily available to all amputees. The astronomical cost of most prosthetic devices is a variable that restricts low income amputee populations from obtaining these vital tools regardless of their level of need, thus highlighting the fact that amputees who are not financially stable are not supported in a fashion that is conducive to their success. Also, cost greatly affects children who suffer from a missing appendage due to the fact that they are in constant need of prosthetic replacement because of physical growth and development. Another issue with the current focus of the prosthetic industry is that it focuses on acquired amputees because this population is much larger in comparison to congenital amputees and thus more lucrative. Congenital amputees' particular needs are often entirely ignored in terms of prosthetic innovation. Finally, low daily utilization is a major issue amongst the amputee population. Several variables exist with the use of prosthetic devices that cause many amputees to decide against the utilization of these tools, like difficulty of use and lack of comfort. This paper will provide solutions to cost, discrimination, issues in development, and daily utilization by emphasizing on how lowering the cost through alternative designs and materials, transitioning the focus of technological development onto the entire amputee population rather than targeting the most lucrative group, and advancing the design in a fashion to which promotes daily utilization will provide the largest level of societal support, so that the amputee population as a whole can maximize their level of productivity in a manner that will allow this group to conquer the hardships that are introduced into their lives due to a missing appendage.
ContributorsO'Connor, Casey Charles (Author) / Popova, Laura (Thesis director) / Graff, Sarah (Committee member) / Department of Psychology (Contributor) / School of Social Work (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This study examines Glamour magazine to determine the messages the publication sends to its readers and to evaluate if such messages align with modern feminist goals. The articles of Glamour's 12 issues from the year of 2016 are analyzed using a framework adapted from previous research on women's magazines. Articles are coded as either positive (feminist, anti-traditional, promotes equality) or negative (anti-feminist, traditional, promotes inequality). Distinct content themes (appearance, dating, home, self-development, career development, politics/world issues, and entertainment) are also examined individually. After the presentation of data, I examine my findings through a feminist lens to determine the nature of the messages being sent to women through the magazine's editorial content, followed by an assessment of the value of women's magazines and how they could potentially shape the beliefs and roles of a 2017 woman. It is found that about half of the articles in Glamour could be considered as having feminist messages, with strong themes of personal choice, individual empowerment, and political involvement or activism in these articles and throughout the magazine. The content also has many blatantly feminist messages, including consistent use of the word itself. Another 40% of the articles are found to be neutral (no clear message to reader), and the remaining are negative. The sexism inherent in these negative articles is critically examined. Finally, the main takeaways of the findings and their ramifications are discussed from both a media consumer and a media producer perspective, with arguments for why it is important to be critical of a magazine's editorial content.
ContributorsAllnatt, Libby Paige (Author) / Pucci, Jessica (Thesis director) / Dove-Viebahn, Aviva (Committee member) / School of Social Transformation (Contributor) / Department of Psychology (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Spousal loss is a common, significant life event that can negatively affect multiple facets of individual health and psychological adjustment. Social support is one factor that is shown to improve adjustment following spousal loss, but much less is known regarding which facet of social support is most predictive of positive adjustment outcomes following spousal loss. This study examined the course of changes in mental health and well-being following spousal loss and which facets of social support are associated with better outcomes following spousal loss. Latent growth curve modeling was applied to data from 265 widowed individuals, ages 65 and older, across four assessments (baseline, and 6-, 18-, and 48- months following spousal loss). I examined the following research questions: (1) adjustment following spousal loss will follow a trajectory of an increase in depressive symptoms and anxiety and decrease in well-being with a leveling-off over time, with between-person differences, and (2) emotional support and instrumental support given will lead to more positive adjustment outcomes over time. Depressive symptoms followed the hypothesized trajectory but anxiety and well-being showed relative stability before and after spousal loss. Instrumental support was the most beneficial facet of social support, such that receiving more instrumental support was associated with lower levels of depressive symptoms and anxiety 6-months following spousal loss. Giving more instrumental support led to an increase in well-being following spousal loss. Instrumental support given and received led to increases in well-being as a function of spousal loss. The discussion focuses on whether and how these findings can help to identify ways through which support and help can be given to individuals to improve adjustment to spousal loss and fully recover.
ContributorsSullivan, Colleen Elizabeth (Author) / Infurna, Frank (Thesis director) / Luthar, Suniya (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Effortful Control (EC) is a person's ability to self-regulate when presented with an environmental stimulus (Rothbart, et al., 2003). It has been well-established that high levels of EC are associated with multiple positive social and academic outcomes in adolescence (Spinrad et al., 2009). Research suggests that parents have a strong impact on numerous child outcomes, such as EC, through both genetic and environmental pathways. Past research has also examined how parents diagnosed with psychopathology contribute to maladaptive outcomes in their children, including poor regulation, through both genetic and environmental processes (Ellis, et al., 1997). However, less is known about the longitudinal effects of parent dysfunction on the child's environment and regulatory abilities and potential mediators of those effects. The current study tested the hypotheses that parent Alcohol Use Disorder (AUD) would specifically predict early adversity, biological mother conscientiousness, and child EC longitudinally and that early adversity and biological mother conscientiousness would predict child EC. Participants were from a longitudinal study of familial alcoholism (N = 195). Regression analyses indicated that parent AUD was not specifically associated with child EC or with biological mother conscientiousness. However, parent AUD was related to higher levels of early adversity. Additionally, biological mother conscientiousness was associated with higher levels of child EC and early adversity was associated with lower levels of child EC when controlling for earlier EC. Given these findings, future research should test mediation models in which parent AUD predicts child EC indirectly through early adversity.
ContributorsRuof, Ariana Kelsey (Author) / Chassin, Laurie (Thesis director) / Elam, Kit (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Dogs' health and wellbeing is of great importance to their owners. The most common nutritional problem for pet dogs is obesity, with 22-40% of pet dogs being classified as overweight or obese. With many adverse health effects associated with obesity, this is a major concern for owners and veterinarians. The degree to which dogs enjoy consuming certain foods can have substantial implications for their body weight, so it is important to understand which aspects of foods make them appealing to dogs. This study aimed to determine whether nutritional aspects of commercial dog foods predict dogs' preferences for those foods. It was found that consumption preference is positively correlated with protein content (p < .001), therefore implying that the protein content of commercial dry dog foods may predict dogs' consumption preferences. Consumption preferences were not predicted by other available measures of food content or caloric value. Dogs' preference for foods high in protein content may be due to the satiating effect of protein. Since foods high in protein both reduce the amount of energy consumed and are found to be palatable to dogs, high-protein dog foods may offer a way for dog food manufacturers, veterinarians, and pet owners to combat obesity in pet dogs.
ContributorsPrevost, Emily Danielle (Author) / Wynne, Clive (Thesis director) / Hall, Nathaniel (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Musical interpretation is challenging when one's goal is to evoke an emotional response from an audience. In order to develop a well-informed interpretation of Mozart's Fantasia in D minor K. 397, a study was conducted on the historical background of the piece and various performances by well-regarded performers. Fantasias are written works, but improvisatory by nature. Mozart's fantasias were influenced by C. P. E. Bach's, which included sudden changes in emotion. An Emil Gilels performance provided a classically trained approach, while Mitsuko Uchida's performance provided an emotional approach. Colin Tilney and John Irving performances elucidated the sound of the instruments that Mozart would have been composing with. Altogether, the research culminated in an interpretation of the D minor Fantasia that endeavored to capture the essence of fantasy, improvisation and emotion.
ContributorsMo, Gina Nan (Author) / Emmery, Laura (Thesis director) / Creviston, Hannah (Committee member) / Department of Psychology (Contributor) / School of International Letters and Cultures (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05