Undergraduate Research Day 2020

Permanent URI for this collectionhttp://hdl.handle.net/1903/20158

With students involved in so many research opportunities, Undergraduate Research Day provides the perfect opportunity for them to share their work with the campus community. Held each April, Undergraduate Research Day showcases current research, scholarship, and artistic endeavors.

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Now showing 1 - 7 of 7
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    Simulating Speech Perception in Bilateral Cochlear Implant Users with Asymmetric Input
    (2020) Zukerman, Danielle; Goupell, Matthew; Jaekel, Brittany; Milvae, Kristina
    Understanding speech in noise is difficult for cochlear-implant (CI) users. One potential reason for this difficulty is asymmetrical hearing between the two ears; that is, when one ear can process sound more effectively and clearly than the other ear. Such asymmetry may impair some CI users’ ability to fuse speech signals from both ears into a single stream. One way to test this is with an alternating speech paradigm, which is an experimental simplification of speech moving from talker to talker in a rapid conversation between a group of people. Previous studies have shown CI users perform 40% worse on alternating speech listening than normal-hearing individuals. The present study aims to examine if reduced alternating speech perception is the result of asymmetrical hearing, which could cause a listener to only use their better ear when listening to alternating speech, and to miss out on much of the signal that is present in the poorer ear. Six young normal-hearing participants were tested using a CI simulation with varying levels of signal degradation to simulate both asymmetrical and symmetrical hearing. The hypothesis was that participants will show selective attention to the ear with the clearer, less degraded signal in asymmetrical hearing conditions, and will overall perform worse in this condition compared to the symmetrical hearing condition. The results comparing the “better ear” and the asymmetric condition suggest that there is no evidence of selective attention; therefore we can reject the hypothesis. Future directions include increasing asymmetry across ears by simulating more drastic degradation in the “poorer ear”. Speech perception in noise is one of the most common issues CI users face, and quantifying the contributions of asymmetrical hearing to this problem is important for resolving this issue.
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    Maternal Anxiety, Temperament & Brain Morphometry in Infancy
    (2020) Margolis, Emma; Filippi, Courtney; Ravi, Sanjana; Bracy, Maya; Pine, Daniel; Fox, Nathan; Filippi, Courtney; Fox, Nathan
    Maternal factors (e.g., maternal anxiety) and infant temperament (e.g., distress to novelty) shape children’s social-emotional development. However, we know relatively little about the impact these factors have on ​infant brain​ development. This study investigates associations between maternal anxiety, distress to novelty (i.e., negative reactivity) and brain morphometry at 4-months. At 4-months, infants’ temperament was assessed by identifying distress in response to novel stimuli. Mothers completed the Beck Anxiety Inventory (BAI) to measure maternal anxiety. Within 2-weeks, high-resolution structural MRI data were acquired during infants’ natural sleep. MRI data were processed using the iBEAT (Dai et al, 2013) pipeline to obtain subcortical and cortical volume estimates. Regression analyses were conducted to investigate whether infant temperament moderated the relation between maternal anxiety and brain volume at a priori selected regions of interest, controlling for total intracranial volume. Results indicate that there was no significant interaction or main effect of temperament. However, there was a main effect of maternal anxiety in all ROIs tested. Greater maternal anxiety predicted larger hippocampus (β=.417,p<.036), amygdala (β=.429,p<.031), superior frontal gyrus (β=.410,p<.041), middle frontal gyrus (β=.411,p<.039), inferior frontal gyrus (β=.404,p<.039), dorsal anterior cingulate cortex (β=.416,p<.039) and posterior cingulate cortex (β=.407,p<.042). This study provides novel evidence that increased maternal anxiety is linked to differences in child-brain morphometry.
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    MRI Processing Pipeline Variability and Infant Brain Morphometry Associations to 4-Month Infant Temperament
    (2020) Foster, Kayla; Filippi, Courtney; Margolis, Emma; Ravi, Sanjana; Bracy, Maya; Pine, Daniel; Fox, Nathan; Fox, Nathan; Filippi, Courtney
    Negative reactive temperament, an infant temperament characterized by fear of novelty, is associated with adolescent amygdala volume (Filippi et al, 2020) and adult prefrontal cortex (PFC) thickness (Schwartz et al, 2010). However, it remains unknown whether these differences in brain morphometry emerge in infancy. Further, evaluating this possibility is a challenge because few pipelines are optimized for processing infant magnetic resonance imaging (MRI) data. Thus, evaluation of available infant MRI processing pipelines is necessary prior to examining associations between negative reactivity and brain morphometry. This study examines (1) which MRI pipeline performs best for 4-month-old infant MRI data and (2) associations between temperament and brain morphometry. Behavioral reactivity was assessed by presenting novel stimuli to infants. High-resolution structural MRI data was acquired a few weeks later. MRI data were processed using the iBEAT (Dai et al, 2013), dHCP (Makropoulos et al, 2018), and CIVET (Ad-Dab’bagh et al., 2006) pipelines to obtain estimates of amygdala and PFC volume. The quality of segmentations of the three pipelines was then assessed. The processing pipelines showed differences in terms of quality of gray/white segmentation and percentage of processing failures. Overall, iBEAT performed the best with the highest percent of useable data. Using the iBEAT output, we examined the associations between infant brain morphometry and reactivity. Results indicated no significant association between amygdala or PFC volume and reactivity.
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    Relations between amygdala:hippocampus ratios and depressive symptoms in typically developing 4- to 8-year-old children
    (2020) Coley, Katherine; Turcios, Miguel; Weinberg, Benjamin; Riggins, Tracy; Riggins, Tracy
    Previous literature suggests that the coordination between the amygdala and hippocampus, regions critical for encoding of complex memory and emotion, are associated with depression and risk factors for depression, such as negative memory bias, during adulthood (Yavas et al., 2019; Gerritsen et al., 2012). Research on adolescents ages 8-17 suggests that increased amygdala:hippocampus ratios are related to the severity of anxiety in pediatric major depression (MacMillan et al., 2003). Although associations between amygdala:hippocampus ratios and depression are well-documented in older samples, these associations are not well-explored in early childhood (i.e., <8 years). Given this is a developmental period during which both the amygdala and the hippocampus undergo structural and functional changes (Riggins et al., 2018; Stern et al., 2019), it may be especially important to understand how these developmental changes relate to depressive symptoms in early childhood. The present research aims to address this gap in the literature. Specifically, we examined depressive symptoms and amygdala:hippocampus ratios in typically developing 4- to 8-year-old children drawn from a larger, longitudinal study on brain development in early childhood (N=200, 100 female; Riggins et al., 2018). Depression scores were assessed using the Children’s Depression Inventory (CDI; Kovacs, 1985). Brain region volumes were collected using a standard resolution (.9mm3), T1-weighted whole brain structural magnetic resonance imaging (MRI) scan and processed using FreeSurfer (v5.1). In addition to amygdala and hippocampal volumes, intracranial volume (ICV) was collected as a control for participant head size. Analysis using partial correlations revealed a significant association between total amygdala:hippocampus ratios and depressive symptoms, r(50) = -.234, p = .048. The association between right amygdala:hippocampus ratios and depressive symptoms approached significance, r(50) = -.218, p = .060, and the association between left amygdala:hippocampus ratios and depressive symptoms were not significant. Contrary to previous research, smaller amygdala:hippocampus ratios predicted increased depressive symptoms. Implications for this research are discussed further.
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    Effects of High Carbohydrate Supplementation on Hepatic Mitochondrial Metabolism
    (2020) Zhang, Christine; Sunny, Nishanth
    Non-alcoholic fatty liver disease (NAFLD) is a major public health issue affecting over 75 million patients and over 70% of patients that suffer from Type 2 Diabetes Mellitus and obesity. Previous research has demonstrated that progression of NAFLD is accompanied by liver mitochondria adaptation and eventual dysfunction as they fail to respond to the influx of free fatty acids and the metabolic actions of insulin. The aim of this study was to elucidate the effects of high carbohydrate supplementation on mitochondrial metabolism, specifically the tricarboxylic acid (TCA) cycle, of hepatocytes utilizing a metabolomics centered approach. Data obtained through gas chromatography mass spectrometry (GC/MS) suggest that LF and HC fed animals exhibit higher mitochondrial (TCA) activity compared to their HF counterparts. Short-term increased mitochondrial activity suggests an increased robust metabolic response, however, long-term effects may be detrimental to metabolic flexibility through increased production of reactive oxygen species. While the comprehensive effects of high carbohydrate supplementation on metabolism are still under investigation, these results suggest that diets high in carbohydrates may lead to exacerbation of mitochondria, and ultimately metabolic dysfunction.
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    Guiding gene-specific methylation of histones in C. elegans
    (2020) Thomas, Shavin; Jose, Antony
    A cell’s function depends on its gene expression, which is controlled by two stores of information: the DNA sequence and the regulatory molecules that interact with DNA. While the information stored within DNA is well-studied, the function of regulatory molecules that influence gene expression is less understood. A key class of regulatory molecules is histone modifiers, which facilitate the methylation, acetylation, and other chemical modifications of histones. These modifications can affect the accessibility of DNA to enzymes that regulate gene expression. Histone modifications are conserved in multiple organisms, from fission yeast to mammals. However, there is contradictory evidence suggesting alternative roles for supposed inhibitory marks. Previous research has used mutations of histone-modifying enzymes to deduce the impact of the histone modifications on gene regulation. However, inferences from such experiments are complicated because the mutation can have an impact on a chromosomal scale, making it difficult to infer about single loci. Therefore, we are developing a dCas9-based platform to target histone modifiers, and their modifications, to a specific locus. Thus far we have found that dCas9 binding alone does not significantly disrupt gene expression within C. elegans, although we detected increased variation within somatic tissues of a ubiquitously expressed gene. Having completed this essential control, we will next introduce a histone modifier that adds H3K36me3 modifications to the same locus through a dCas9 fusion protein and determine its impacts on gene expression.
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    Relations between Memory Measures and Hippocampal Volumes in Early Childhood
    (2020) Fine, Carli; Riggins, Tracy
    The phenomenon of childhood amnesia, in which only a mere fraction of childhood experiences is remembered, may be due to changes in underlying neural mechanisms supporting memory (Willoughby et al., 2012; Bauer, 2007). However, it is unknown whether lab tasks used to measure childhood memory skills map onto everyday life experiences. This study aims to address that gap through an investigation of two different measures completed by 200 4- to 8-year-old children. One task is a rich open-ended autobiographical interview examining recall for real-world events; the other is a controlled laboratory-based assessment examining memory for temporal order using a series of child-appropriate pictures. This study asks whether both tasks show relations to 1) age group, 2) underlying neural mechanisms, and 3) performance as compared to each other. The hippocampus is a likely candidate underlying behavioral changes during early childhood because it undergoes significant development during this time (Gogtay et al., 2006; Lavenex & Lavenex, 2013) and supports memory in school-aged children and adults (Ghetti & Bunge, 2012). Autobiographical memories were scored using a modified interview coding scheme based on Levine et al. (2002). Temporal order was scored as proportion of adjacent pictures correctly ordered across two 9-item sequences. Hippocampal subregions were delineated using manually identified anatomical landmarks (Riggins et al., 2018). Preliminary results indicate age-related performance differences and hippocampal volume correlations. This work contributes to knowledge about the extent to which naturalistic versus lab-based tasks similarly measure memory abilities.