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
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Item Relations Between Latent Episodic Memory, Nap Habituality, and the Cortex During Childhood(2023) Allard, Tamara Lynn; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)During childhood, episodic memory demonstrates marked improvements that are supported by the protracted development of the hippocampus and a larger network of cortical regions. To date, most research has focused on associations with the hippocampus in this age group. Few studies have explored the contribution of cortical regions and no studies have explored this longitudinally. Thus, the first aim of this dissertation was to examine the longitudinal co-development of cortical thickness and surface area in memory-related cortical regions with a latent episodic memory variable in 4- to 8-year-old children (N = 177). Findings, uncorrected for multiple comparisons, demonstrated that a thinner cortex in multiple episodic memory network regions (i.e., inferior frontal gyrus, inferior parietal sulcus, lingual gyrus, middle temporal gyrus, precuneus, lateral occipital cortex, superior frontal gyrus, superior parietal lobule, superior temporal gyrus, and temporal pole) at age 4 predicted more rapid improvements in memory performance from age 4 to 6 years. Similarly, greater surface area in the precuneus and less surface area in the medial orbitofrontal gyrus at age 4 also predicted more rapid improvements in memory performance from age 4 to 6 years. Additionally, results revealed that several regions demonstrate parallel co-development with latent episodic memory performance from age 4 to 8 years. Specifically, greater changes in cortical thickness and surface area of the entorhinal cortex were associated with greater changes in memory from age 4 to 6 years. Furthermore, cortical thickness of entorhinal cortex and surface area of anterior cingulate cortex, entorhinal cortex, inferior parietal sulcus, lingual gyrus, and superior temporal gyrus showed co-development with latent episodic memory from age 6 to 8 years. Together, these findings suggest that cortical thickness and surface area of the episodic memory network support improvements in memory performance during childhood. However, these findings did not survive correction for multiple comparisons. Although age-related differences were one focus of this investigation, individual differences were another. Specifically, during childhood children transition away from afternoon napping. This transition has previously been associated with differences in memory consolidation abilities and hippocampal maturation. These associations suggest that habitual nappers require more regular sleep to consolidate memories due to an immature episodic memory network. However, limited work has examined these associations outside the hippocampus. Therefore, the second aim of this dissertation was to examine whether regions that support longitudinal memory development differ as a function of nap habituality (N = 44). Findings revealed significant differences in cortical thickness of right inferior frontal gyrus and surface area of lateral occipital cortex, such that non-nappers demonstrated a thinner cortex and greater surface area in these regions compared to nappers, though these findings did not survive correction for multiple comparisons. Thus, although there is some evidence that memory-related cortical regions may differ based on nap habituality, additional work is needed to support this claim. Together this dissertation provides new data on the co-development of memory with brain structure in the episodic memory network and identifies individual differences that may be associated with these brain structures.Item DIRECTIONAL RELATIONS OF CHILD ANXIETY AND PARENTING ACROSS EARLY INTERVENTIONS FOR INHIBITED YOUNG CHILDREN(2022) Novick, Danielle; Chronis-Tuscano, Andrea; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Given the robust evidence-base for the efficacy of cognitive behavioral therapies (CBTs) in reducing youth anxiety disorders, researchers have moved beyond efficacy outcome analysis to better understand how such interventions operate (i.e., mediation). However, the majority of this research has examined mechanisms of change in CBTs targeting anxiety in school-age youth or adolescents, and applying such findings to younger children may be misguided. Grounded in developmental-transactional models, interventions for younger children with or at risk for anxiety tend to target key parenting and child factors implicated in the early emergence and maintenance of anxiety. Nevertheless, the directional and temporal relations among these child and parenting factors in the context of early interventions remain unknown. The current study thus builds on previous studies of CBT for older youth to elucidate mechanisms of change and treatment directionality within two early interventions for young children (N = 151) at risk for anxiety by virtue of behavioral inhibition: The multi-component Turtle Program and the parent-only Cool Little Kids program. Reciprocal relations between parent-reported child anxiety, observed parenting (negative control and positive affect), and parent-reported accommodation of child anxiety were examined across 4 timepoints (pre-, mid-, and post-treatment, and one-year follow-up). Study hypotheses were tested via 1) a traditional cross-lagged panel model (CLPM), 2) a latent curve model with structured residuals (LCM-SR), and 3) a latent change score model (LCS). Results were consistent with the child-to-parent influences found in previous research on CBT for older anxious youth. However, after extending the traditional CLPM to parse within- and between-person effects in the LCM-SR, these results only remained in Turtle. LCS analyses revealed bidirectional effects of changes in parent accommodation and changes in child anxiety during and after the intervention, but only in Turtle. Our findings coincide with developmental-transactional models suggesting that the development of child anxiety may be the result of child-to-parent influences rather than just the reverse, and highlight the importance of targeting parent and child factors simultaneously in early interventions for young inhibited children and their parents.Item Island Constraints: What is there for children to learn?(2022) Hirzel, Mina; Lidz, Jeffrey; Lau, Ellen; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation presents behavioral studies that target the early syntactic representations of wh-movement during infancy and early childhood. Previous studies show that by 20 months-old, infants represent wh-movement and use this knowledge to respond to wh-questions during language comprehension tasks (Gagliardi 2012; Gagliardi et al., 2016; Seidl et al., 2003). Studies probing the nature of early representations of wh-movement show that by around 4 years-old, children represent island constraints (e.g., de Villiers et al., 1990; de Villiers & Roeper, 1995a, 1995b; Fetters & Lidz, 2016; Goodluck et al., 1992). It remains unclear how knowledge of wh-movement develops. What is the source of this ‘empirical gap’ between the onset of knowledge of wh- movement, and the observation that children respect island constraints? One possibility is that knowledge of island constraints is a component of Universal Grammar (e.g., Chomsky 1965, 1986; Hornstein & Lightfoot 1981). In this case, the ‘empirical gap’ in the linguistic abilities of infants compared to young children isn’t indicative of their linguistic knowledge, but rather the difficulties with testing infants and toddlers on complex syntax. Another possibility is that knowledge of island constraints is acquired via experience (e.g., Pearl & Sprouse, 2013). In this case, the ‘empirical gap’ reflects a knowledge gap, and there’s no evidence for knowledge of island constraints during infancy because it has yet to be acquired. Experiment 1 shows that by 19 months-old, infants have knowledge of wh-movement, and use this knowledge during language comprehension. Results are consistent with recent work which shows that 18 month-olds, but not 17 month-olds, know that wh-phrases co-occur with gap positions in wh-object questions (Perkins & Lidz, 2021). Experiment 2 shows that 3 year-olds respect locality constraints on wh-movement in wh- questions, and Experiment 3 shows that adults behave as expected on this task. Experiments 4 and 5 test children and adults on locality constraints on wh- movement in relative clauses, but these results are inconclusive (likely due to difficulties with moving the task online). The results of Experiment 3 raises challenges for learning hypotheses of island constraints which emphasize the role of linguistic experience. Learning models which propose that linguistic experience is the key factor in the acquisition of island constraints must consider these behavioral results when estimating the amount of data that the learner needs to solve the acquisition problem. These behavioral results are consistent with the hypothesis that knowledge of island constraints is innate, but further work is needed to close the ‘empirical gap’ between the onset of knowledge of wh- movement and the onset of knowledge of island constraints.