Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item The Role of Cognitive Control in Bilingual Code-Switch Comprehension(2021) Salig, Lauren; Novick, Jared; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Bilinguals experience a conflict when comprehending a sentence that code-switches from one language to another. However, why bilinguals experience conflict during code-switch comprehension is unclear. This study asks: Does being in a cognitive state conducive to resolving conflict help bilinguals read code-switches faster? If so, it would indicate that comprehending a code-switch involves conflict at an early lexical/syntactic level because faster resolution of the conflict would facilitate faster code-switch reading. 101 Spanish-English bilinguals completed Flanker-arrow trials to manipulate their engagement of cognitive control—which regulates conflict detection and resolution. Immediately after this cognitive-control manipulation, bilinguals read code-switched or unilingual sentences. Having cognitive control engaged prior to encountering a code-switch did not result in faster reading of code-switches. This finding provides preliminary evidence that reading a code-switch may not involve conflict at a lexical/syntactic level. Future work should further investigate the type of conflict that bilinguals encounter during code-switch comprehension.Item Executive Function, Engagement, and Attention: Effects on Comprehension(2021) Mohan, Svetha; Bolger, Donald J; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cognitive control/executive function (EF) and attention deficits are prevalent among students and impact comprehension performance. While EF and attention impairments are well-studied, the interaction between cognitive control/EF, attention, arousal/engagement, and comprehension has yet to be explored. Undergraduates’ ADHD symptoms, cognitive abilities, and cognitive control were assessed prior to listening to passages of varying degrees of emotional valence and responding to comprehension questions. Exploratory EEG data were also collected to examine patterns of cognitive engagement/emotional arousal. Results showed that comprehension for participants with high numbers of ADHD symptoms and/or proactive cognitive control types were influenced by the emotional valence of the context. In emotional contexts, those with high ADHD symptoms showed better comprehension overall and deep levels of processing, and those with proactive cognitive control types showed better deep processing. These findings indicate the need for further research to tease apart the interaction of EF, attention, and arousal on comprehension across different contexts.Item Executive function in aphasia: is there a bilingual advantage?(2013) Baughman, Susan; Faroqi-Shah, Yasmeen; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Previous studies have demonstrated that there is a bilingual advantage in neurotypical populations on tasks of executive functions, particularly inhibition. However, little research has been conducted on a population with aphasia. This study examined whether bilingual persons with aphasia (BPWA) and monolingual persons with aphasia (MPWA) displayed any differences on tasks of executive functions. Four BPWA and four MPWA matched for age and Western Aphasia Battery subtest scores were administered a linguistic Stroop task, a nonlinguistic Stroop task, a trail-making task, and a non-verbal memory task. Results demonstrated that the two groups did not have significantly different scores on any of the tasks. While both groups of PWA were slower than neurotypical adults on reaction time measures, accuracy on all four tasks was unimpaired and within the normal range. These results, although preliminary given the small sample size and high performance accuracy, suggest that there may not be a clear "bilingual advantage" on tasks of executive function.Item CARDIOVASCULAR FITNESS MODIFIES THE RELATIONSHIP BETWEEN GENOTYPE AND NEUROCOGNITIVE FUNCTION DURING EXECUTIVE CHALLENGE IN LATE ADOLESCENCE(2008-11-06) Woo, Minjung; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cardiovascular fitness and physical activity have been positively associated with executive cognitive functioning (i.e., planning, scheduling, coordinating, response inhibition, and working memory), which rely on the frontal region of the brain. Recent studies suggest that the benefit is particularly strong in middle-aged individuals who carry the Apolipoprotein (ApoE) e4 allele, a known genetic risk factor for Alzheimer's disease (AD). However, there have been no studies to determine this interactive relationship in adolescents. Therefore, the present study examined if cardiovascular fitness mediates the relationship between genotype and cerebral cortical responses in college-age males during a frontally-mediated executive challenge. Twenty nine e4 carriers (N=29; 15 high-fit, 14 low-fit) and thirty non-carriers (N=30; 15 high-fit, 15 low-fit) were stratified by cardiovascular fitness. Cognitive function was assessed by neuroelectric response, event-related potentials (ERPs) recorded at 11 sites (F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1 and O2) to both an auditory Go-nogo executive task (ECF) and a non-executive Oddball task (non-ECF). The P300 amplitude, which is indicative of the recruitment of attentional resources, exhibited by the high-fit e4 carriers was higher relative to that observed in the low-fit e4 carriers during both the ECF and non-ECF tasks. Importantly, the high-fit e4 carriers were also undifferentiated from both groups of the non-carriers. Furthermore, high-fit individuals, regardless of genotype, exhibited shorter P300 latency than did the low-fit individuals at sites Fz, Cz and Pz during ECF task and site Pz during non-ECF task. The current findings revealed genetic specificity in the relationship between cardiovascular fitness and the brain processes indexed by P300 amplitude function during late adolescence in response to both ECF and non-ECF challenge, with greater benefit incurred for the ECF task. The results suggest that cardiovascular fitness in e4 carriers is protective against the susceptibility to the liabilities (i.e., hypometabolism and cortical thinning) associated with this allele.