Tag: Interact & React

Language Proficiency and Lexical-Semantic Processing in Bilingual Toddlers

Presenter(s): Abbey Ward—Communication Disorders and Sciences; Spanish

Faculty Mentor(s): Stephanie De Anda

Session 6: Interact & React

Prior research suggests that language systems are not entirely separate but interact in bilingual individuals . The current study seeks to extend prior work by investigating whether or not bilingual toddlers organize vocabulary words and their meanings (i .e ., lexical-semantic networks) within and across languages as early as 2 years of age . Of interest is how the words a toddler hears (i .e ., language exposure) versus the words that they say (i .e ., language proficiency) influence this organization of dual vocabulary systems . This study presents findings from a group of Spanish- English bilingual toddlers (N = 20, Mage = 24 .65 months) to examine the association between (a) language exposure and (b) language proficiency with lexical-semantic processing . Four measures were used: the Language Exposure Assessment Tool (LEAT) captured exposure, whereas the Computerized Comprehension Task (CCT) and the English-Spanish Vocabulary Inventories (ESVI) measured vocabulary size in both languages . Lastly, eye-tracking measures assessed lexical- semantic processing within and across Spanish and English . Consistent with prior literature, results suggest that vocabulary systems interact in bilingual toddlers by 24 months of age . As a group, toddlers with larger vocabulary sizes and faster speed of word recognition in their stronger language (Spanish) demonstrated inhibition, such that they were more likely to efficiently discard words similar in meaning (i .e ., semantic competitors) in order to correctly identify the target . When processing semantic relationships between words in their weaker language (English), toddlers with slower speed of word recognition demonstrated facilitation in order to continue ongoing activation of their sparse vocabulary networks . However, language exposure was not associated with lexical- semantic processing . Together these findings demonstrate that the words bilingual toddlers say and understand (and not necessarily what they hear) influence the organization of dual language systems . Ultimately, our findings contribute to the current understanding of bilingual first language acquisition and emerging theoretical models on bilingual language development .

Defining the roles of conserved DNA repair complexes in maintenance of C. elegans meiotic genome integrity

Presenter(s): Alina Salagean—Biology

Faculty Mentor(s): Erik Toraason, Diana Libuda

Session 6: Interact & React

Most organisms utilize meiosis, a specialized form of cell division, to produce reproductive cells such as sperm and eggs . Failure to maintain genomic integrity during meiosis can result in serious diseases, including infertility and cancer . The Structural Maintenance of Chromosomes 5/6 complex (SMC-5/6), its E3 SUMO ligase subunit NSE-2, and the BRCA1/BARD1 heterodimer are conserved protein complexes implicated in ensuring accurate meiotic DNA repair and are known to genetically interact . However, the specific mechanisms by which these proteins interact to preserve genome integrity is unknown . To determine the NSE-2 specific and NSE-2 independent meiotic functions of the SMC- 5/6 complex in meiotic DSB repair, we utilized immunofluorescence imaging and a mortal germline phenotype assay to assess smc-5 and nse-2 C . elegans mutants . Our findings suggest a separation of function within the SMC-5/6 complex, which performs NSE-2 dependent functions promoting efficient meiotic DSB repair and NSE-2 independent functions in preservation of germline immortality . Finally, to define epistatic relationships between BRC-1/BRD-1, SMC-5/6, and NSE-2 in DNA repair, we assessed the germline sensitivity to exogenous DNA damage by scoring the brood viability of pairwise brc-1, smc-5, and nse-2 double mutants . These data reveal that exogenous DNA damage repair is differentially regulated within meiotic prophase I and implicate SMC-5/6 as a central regulator of both NSE-2 and BRC-1 dependent DSB repair . Taken together, our research defines fundamental genetic mechanisms and interactions preserving genomic integrity .

Electrical brain waves modulate with movement speed and uncertainty

Presenter(s): Ryan Leriche—Biology

Faculty Mentor(s): Ryan Leriche

Session 6: Interact & React

We investigated how brain electrical activity changes with movement speed and movement uncertainty . Understanding the electrophysiological profile of movement speed could have applications for Parkinson’s Disease while movement uncertainty may be an ignored confound across many experiments .

We used a computerized task to manipulate participants to move more slowly or more quickly . In addition to these “slow” and “fast” blocks, our task manipulated the certainty of an upcoming movement . When participants knew when they were going to move this was known as a “certain” block . Conversely, during “uncertain” blocks, participants were not sure when they were going to move . Movement speed (slow or fast) and movement uncertainty (certain or uncertain) blocks were paired together creating four possible blocks: fast-certain, fast-uncertain, slow-certain, and slow- uncertain . Scalp-electro-encephalography (EEG) was recorded from 12 participants during this task to examine their brain activity . We looked at the electrical activity in the beta (13-30 Hz) frequency range over the sensorimotor cortex . Our findings suggest that beta-band activity is elevated in during slower movements . The slow-uncertain block had increased beta power compared to the fast- uncertain block during movement preparation . Our other results are less conclusive .

Robo4 Project

Presenter(s): Byron Lee—Human Physiology

Faculty Mentor(s): Ashley Walker

Session 6: Interact & React

Aging is associated with the impairment of the neurovascular unit, and this potentially leads to increased Alzheimer’s disease pathology and cognitive impairment . A specific axon guidance receptor, Robo4, is important in maintaining the structure and restrictive barrier of the blood-brain barrier (BBB) . We predicted that the knockout of Robo4, and the subsequent increase in BBB permeability, will result in cognitive dysfunction . Therefore, Robo4 signaling pathways may potentially be a valuable target for therapeutic treatments of AD . In the present study, we studied Robo4 knockout (Robo4 -/-) and wild type (Robo4 +/+) mice crossed with mice containing mutations in amyloid precursor protein (APP), leading to greater aberrant amyloid-beta production . To examine the effect of aging, we studied young and old wildtype C57BL6 mice . We assessed cognitive function by conducting Nest Building tests and Morris Water Maze . We found that old C57BL6 mice had impaired cognitive function compared to young C57BL6 mice . However, when Robo4 x APP groups were compared, we found no differences in cognitive function . These preliminary results suggest that aging has a stronger effect on cognitive function than Robo4 knockout . Additional studies are needed to determine the effect of Robo4 knockout on blood-brain barrier permeability and amyloid-beta accumulation .

Impacts of Environment on Degree of Despotism in Semi-Free Ranging Japanese Macaques (Macaca Fuscata)

Presenter(s): Lisa Kwan—Anthropology, French

Co-Presenter(s): Noa Cohen

Faculty Mentor(s): Kylen Gartland, Frances White

Session 6: Interact & React

Primate societies have evolved social hierarchies when higher ranking individuals can gain access to differential benefits such as food resources and mating opportunities . In order to maintain high rank, individuals must uphold the social hierarchy and defend their position against lower- ranking primates . Different primate groups have varying degrees of hierarchical flexibility in which a population is despotic or tolerant depending on which confers individual benefit . This is often dependent on the particular environment . Tolerant hierarchies are typically seen in environments where group cohesion and cooperation are important for individual success, and are characterized by low rates of severe wounding, sharing of limited food resources, and frequent reconciliation following aggressive interactions . In contrast, despotic hierarchies are found where individuals can gain benefits by competing amongst each other for access to resources . They are distinguished by frequent aggression and wounding between individuals, restricted access to resources, and infrequent reconciliation . Japanese macaques (Macaca fuscata) are primarily characterized as having despotic hierarchies . Our research examines potential differences in hierarchies of Japanese macaques in wild and captive settings due to differences in abundance and distribution of resources between the two environments . Through an examination of published studies, we will compare and contrast the environmental factors associated with despotic versus tolerant hierarchies in Japanese macaques . We will collect data on the Japanese macaque group at the Oregon National Primate Research Center (ONPRC) . This research may provide insight into how different captive and wild environments affect primate behavior .

Visual Input Principally Drives Zebrafish Social Behavior

Presenter(s): Adeline Fecker—Biology

Faculty Mentor(s): Phil Washbourne

Session 6: Interact & React

Disruption in social behavior is characteristic of Autism Spectrum Disorder, a neurodevelopmental disorder that appears in early childhood . Previous experiments in zebrafish showed lesioning of the ventral forebrain reduced social engagement . Results also suggested subjects must be able to see each other to socialize (Stednitz, 2018) . Subsequent experiments demonstrated that zebrafish can interact without vision, perhaps using their other senses like the water-pressure mechanosensory and olfactory system . Our study investigates how sensory modalities contribute to social behavior . Measuring behavior in an open field allows for quantification of complex social behaviors like orienting, following, and dispersing . We manipulated sensory modalities by recording behavior in the dark and lateral line ablated conditions . Our results show the loss of the visual input causes a 20% reduction in orienting behaviors but no reduction in following behavior . When we ablate visual input and mechanosensation, we do not observe a reduction in orienting or following behaviors . Another outstanding question is which brain regions are activated during social behavior by the contributing senses . We use whole brain immunolabeling with neuronal activity markers as an unbiased approach to identifying and quantifying active brain regions in social and alone conditions . We found the anterior dorsal pallium of the forebrain is significantly more active in social than alone conditions . Further analysis will reveal regions of activity due to manipulated sensory modalities . Our study of behavior and corresponding brain activity sheds light on the importance of sensory modalities and the anterior dorsal pallium in social behavior of zebrafish .

Association between a non-invasive assessment of frailty and vascular dysfunction in old mice

Presenter(s): Jazmin Cole—Human Physiology, Biology

Faculty Mentor(s): Ashley Walker

Session 6: Interact & React

Advancing age is characterized by not only an increased risk for cardiovascular diseases (CVDs), but also a decline in functional reserve and impaired adaptive capacity across multiple physiologic systems, also known as frailty . Impaired vascular function is a known contributor to CVDs and potentially has a role in increased frailty . In patients with overt disease, measures of frailty are related to vascular endothelial cell dysfunction . However, the relation between vascular endothelial function and frailty in a non-disease population is unknown .

To examine the relation between vascular function and frailty in the context of similar genetics and environment, we studied wildtype C57BL/6 mice . In young (9 mo, n=7) and old (23-30 mo, n=27) male and female mice, we assessed endothelial-dependent dilation (EDD) ex vivo in isolated, pressurized mesentery arteries and middle cerebral arteries (MCA) . Mouse frailty was assessed using a previously established non-invasive 31-item frailty index based on clinical signs of deterioration . The severity of each deficit was assessed by two independent observers and assigned a value between 0-1, with a higher score indicating more severe frailty .

Frailty index was ~6 fold greater in old compared with young mice (p<0 .001) . Among the old mice, frailty index was correlated with mesentery artery maximal EDD (r=-0 .53 p=0 .002), and remained significant after controlling for age (partial correlation: r=-0 .38, p=0 .03) .

This study demonstrates that frailty, independent of age, is associated with mesentery artery endothelial dysfunction in wildtype, non-diseased mice . However, it remains unknown whether the mesentery artery dysfunction is a cause or consequence of the greater frailty . Interestingly, we found a lack of association between frailty and cerebral artery endothelial function . Future research is needed to determine the mechanisms linking frailty and mesentery artery dysfunction .

The Reactions Between Iron and Selenium

Presenter(s): Dylan Bardgett—Chemistry

Faculty Mentor(s): Dave Johnson, Danielle Hamann

Session 6: Interact & React

In the wake of the recent discovery of high-temperature superconductivity in iron selenide, FeSe, chemists, physicists, and materials scientists from around the globe have tried to develop new FeSe- based materials with higher and higher superconducting critical temperatures . However, none have yet explored the fundamental chemistry of how Fe and Se react . We investigated the interactions between solid Fe and Se in the absence of the diffusion limitations often confronted in solid state chemistry by preparing layered precursors of elemental Fe and Se with layer thicknesses on the order of a few angstroms with a variety of Fe/Se compositions . The initial structures and subsequent reactions were monitored via x-ray diffraction and x-ray fluorescence as the precursors were gently annealed . Structural and compositional analysis of the samples indicates that, unlike other transition metal selenides, the reactions between Fe and Se are not kinetically limited by diffusion processes . Even at temperatures well below standard reaction temperatures, thermodynamic products between Fe and Se appear to dominate the macro-architecture of the precursors . These findings may hold significant consequences for the development of future FeSe-based materials, as the low reaction barriers to form the thermodynamic products may impede efforts to kinetically trap metastable FeSe materials .