Psychology
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Item Assessing the Impact of Typical Variations in Stressful Life Events on Hippocampal Development in Childhood(2021) Botdorf, Morgan; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The negative impact of extreme stress on early brain development is well-documented. An emerging body of work suggests that less extreme and more typical variations in stressful experiences (e.g., parental divorce, changing schools) may also exert an impact on the brain, especially in early childhood; however, more systematic research is needed. Across, three studies, this dissertation addressed this gap by exploring effects of typical variations in stressful life events on development of the hippocampus, a brain region highly susceptible to stress. Study 1a assessed the impact of stressful life events on the development of hippocampal subfield volumes (i.e., CA1, CA2-4/dentate gyrus (DG), subiculum) in an accelerated longitudinal sample of 102 4- or 6-year-old children who were each followed for 3 years. Analyses revealed that experiencing more stressful life events was related to smaller CA1 and CA2-4/DG volumes in the 6- (but not 4-) year-old cohort. Study 1b used the same sample described in Study 1a to investigate the impact of stressful life events on functional connectivity between the hippocampus and stress-related cortical regions. Analyses revealed a significant association in the 4- (but not 6-) year-old cohort, such that experiencing more stressful life events was related to greater connectivity between the hippocampus and the insula, a region important for emotional processing. Study 2 assessed moderating effects of sex and socioeconomic status (SES) on the association between stressful events and hippocampal subfield volumes using a large (n = 4,348), diverse subsample of 9-10-year-old adolescents from the Adolescent Brain and Cognitive Development Study. Analyses revealed that stressful life events were related to smaller subiculum volumes, but these associations did not vary by sex or SES. Overall, these findings provide evidence of the impact of typical variations in stressful life events on both hippocampal structure and functional connectivity. Findings also highlight the complexity of stress effects on the brain as these experiences may impact the hippocampus in an age-dependent manner. These results advance our current understanding of how stress influences hippocampal development and pave the way for studies to assess the implications of findings both for cognitive processes and the development of stress-related disorders.Item Development of the Episodic Memory Network in Early Childhood: Insights from Graph Theoretical Analysis(2019) Botdorf, Morgan Anna; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The hippocampal memory network has been identified in both children and adults and shown to be related to episodic memory ability. However, it remains unclear how its organization may differ across development, particularly during periods of large behavioral gains in memory ability. The goal of the present study was to utilize graph theoretical analysis to investigate the integration of the hippocampus within the memory network and segregation from other networks (i.e., fronto-parietal and cingulo-opercular attention networks) in the brain. Results indicated that with age, there was a general increase in connections between the hippocampus and both regions within the memory network and regions in other networks in the brain. These differences may contribute to improvements in memory typically observed in early childhood. Future analyses will examine relations with memory behavior and probe whether segregation is observed using other metrics, a sample of adult data, or other networks (e.g., sensorimotor).Item Development of subjective and objective recollection: Evidence from event-related potentials(2014) Rollins, Leslie Ann Hainley; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Memory, particularly memory for contextual details (i.e., recollection), undergoes significant development from middle childhood to young adulthood. This research examined the development of recollection utilizing participant's subjective reports as well as their objective accuracy for two contextual details (i.e., the color of the item and a semantic judgment made during encoding). The aims of the present studies were to examine age-related differences in subjective and objective recollection, the correspondence between these abilities, and their neural correlates. Participants included 6- to 8-year-old children, 12- to 13-year-old adolescents, and young adults. Event-related potentials (ERPs) were recorded during the encoding (Study 1) and retrieval (Study 2) portions of a memory paradigm. Age-related improvements in objective and subjective recollection were found in both studies. At encoding, ERP indices of recollection were present when recollection was indexed subjectively or by accuracy for the semantic judgment made during encoding. In contrast, ERP responses were not sensitive to recollection when memory for color was used as the measure of recollection. ERP effects associated with recollection at encoding were not influenced by age. This finding suggests that children, adolescents, and adults process items similarly at the encoding stage. During retrieval, a recollection effect was only present when recollection was indexed by subjective judgments. Further, this effect was influenced by participant age. The effect was absent in children, topographically widespread in adolescents, and, consistent with previous literature (for review see Rugg & Curran, 2007), maximal over left centro-parietal leads in adults. Collectively, these findings suggest that ERP effects associated with recollection may be more apparent using subjective versus objective measures and that improvement in memory performance from middle childhood to adulthood is primarily attributable to the development of consolidation, storage, or retrieval processes.Item INFLUENCE OF EXECUTIVE FUNCTIONING ON MEMORY FOR CONTEXTUAL DETAILS AND FALSE RECOGNITION(2012) Rollins, Leslie Ann Hainley; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)No previous studies had examined how all constructs of executive functioning (i.e., conflict inhibition, delay inhibition, cognitive flexibility, and working memory) relate to memory for contextual details and false recognition in early childhood controlling for general intelligence. Three and six-year-old children performed a laboratory-based episodic memory task and a battery of neuropsychological tasks. The relation between executive functioning and false recognition was diminished taking general intellectual ability into account. Executive functioning did not predict memory for contextual details in the full sample. However, when children who were at chance at recalling contextual details were excluded from analysis, executive functioning showed a trend for accounting for variance beyond age group and general intellectual ability. The inability of this effect to reach conventional statistical significance was likely due low statistical power resulting from the sample size reduction. Specifically, accuracy on the day/night task, a measure of conflict inhibition, was a significant predictor.