Theses and dissertations

This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students. 

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The Comparison of Frontostriatal Tracts Between Adolescents with ADHD and a Typically Developing Adolescent Control Group

Description
The frontostriatal reward circuit serves an underlying role in reward processing, cognitive planning, and motor control in the context of achieving a goal. Furthermore, research suggests a relationship between the reward circuits and behavior expressed in Attention Deficit Hyperactivity Disorder (ADHD); however, the specific structural differences of the reward circuits…

The frontostriatal reward circuit serves an underlying role in reward processing, cognitive planning, and motor control in the context of achieving a goal. Furthermore, research suggests a relationship between the reward circuits and behavior expressed in Attention Deficit Hyperactivity Disorder (ADHD); however, the specific structural differences of the reward circuits in those with ADHD remain ambiguous. Diffusion tensor imaging (DTI) techniques were used to analyze diffusion weighted magnetic resonance imaging (DWI) data in order to examine the structural connectivity of frontostriatal reward pathways in ADHD adolescents compared to typically developing (TD) adolescents. It was hypothesized that measures of impulsivity would be predicted by white matter tract integrity measures in frontostriatal tracts related to affective processing (ventromedial prefrontal cortex to ventral striatum, vmPFC) in adolescents with ADHD, and that there would be reduced tract integrity in tracts related to executive control (dorsolateral prefrontal and anterior cingulate cortex—dlPFC and ACC, respectively). Frontostriatal tracts as well as the hippocampus and amygdala were examined in relation to age and impulsivity using both correlation and regression models. Results indicated that impulsivity declined with age in the TD group while no significant trend was identified for the ADHD group. The hypotheses were not supported and results for both predictions on the affective and executive circuits showed opposite trends from what was expected.
ContributorsHarrison, Sydney Rae (Author) / McClure, Samuel (Thesis director) / Brewer, Gene (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
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Effects of Phonotactic Probability during Early Novel Word Recognition

Description
The goal of this study was to examine whether there is any effect of phonotactic probability during the early phases of novel word recognition. In order to determine this, I performed two experiments. In Experiment 1, 33 adult monolingual English speakers learned 24 novel word-object pairings, half of which were…

The goal of this study was to examine whether there is any effect of phonotactic probability during the early phases of novel word recognition. In order to determine this, I performed two experiments. In Experiment 1, 33 adult monolingual English speakers learned 24 novel word-object pairings, half of which were high English phonotactic probability words and the other half were low English phonotactic probability words. I additionally included three conditions that varied the amount of exposures to each novel word-object pairing (i.e. One Exposure Condition, Two Exposures Conditions, and Five Exposures Condition). Experiment 2 was designed to clarify results found in Experiment 1, with improved randomization and fewer conditions (i.e. One Exposure Condition and Five Exposures Condition). The findings from both experiments were statistically significant in accuracy for Training condition, but not statistically significant for phonotactic probability nor for an interaction between phonotactic probability and Training condition. Although participants demonstrated learning across conditions there is no indication of a relationship between high and low phonotactic probability and novel word recognition. Collectively, these findings suggest that future studies will be necessary to determine if there is indeed an effect of phonotactic probability on early novel word recognition.
ContributorsQuinones, Sara Cristina (Co-author) / Quiñones, Sara (Co-author) / Benitez, Viridiana (Thesis director) / Tecedor Cabrero, Marta (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Dean, W.P. Carey School of Business (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05