Tag: Poster 31

Mapping the Human Primary Somatosensory Cortex Using Dense-array EEG: An Analysis of the Somatosensory Evoked Potential

Presenter: Kyle Morgan

Mentor: Don Tucker

AM Poster Presentation

Poster 31

In principle, dense-array EEG (dEEG) technology has the ability to localize cortical brain activity with adequate spatial resolution such that anatomically and functionally distinct regions can be studied. The present study employs dEEG to map activity of the primary somatosensory cortex (SI), which is functionally and anatomically defined. EEG recordings were acquired from 10 participants as their thumbs were stimulated by a custom-made piezoelectric stimulator. Early components of the somatosensory evoked potential (SEP), which reflect activity from SI, were evaluated in individual participants to assess topographic distribution at the scalp. In a subset of participants, we build high-resolution electric head models that describe how current propagates from the cortex to the scalp surface, where the SEP is measured, and we use this model to localize the early SEP components. We report on the localization accuracy relative to the expected location (SI).

Carbon and Nitrogen Mineralization in a Manipulated Northern Hardwood Forest Soil: Do Plants’ Allocation Strategies Help Set the Size and Responsiveness of Soil Organic Matter Pools?

Presenter : Geoffrey Johnson

Mentor : Scott Bridgham

Major : Environmental Science

Poster 31

Plant litter from aboveground and belowground production constitutes a major carbon (C) and nutrient input to forest soils worldwide. Uncertainty in the relative effects of these two biomass allocations on ecosystem structure and function is the impetus for the Detritus Input Removal and Transfer (DIRT) experiment, which incorporates root trenching and leaf litter removal and addition. In this study, we sampled mineral soils from DIRT plots at a temperate hardwood forest in Northwestern Pennsylvania in the 0-10 cm depth for all treatments and additional organic horizon and 10-20 cm profile depths for control (CO) and double litter (DL). This DIRT site was established in 1991. By incubating samples at 35°C and near-optimal moisture content for 56 weeks, we estimated maximum potential respiration and net nitrogen (N) mineralization and used the resulting cumulative values to compare rate constants and pool sizes for 1 and 2 pool exponential models among treatments. Net N mineralization in DL plots was significantly greater than CO (α=0.05) at 10- 20 cm, while the no input (NI) treatment was significantly less than CO and DL (α=0.05) at 0-10 cm. We also provide evidence that the treatment effects will continue to become more significant on longer time-frames. From these results, we suggest soil C and N pools are affected by plant litter allocation ratios on decadal time scales, and the most rapid effects may be outside of the pools in the uppermost mineral soil horizons.

Saturating the Neurospora Genome for Mutants Defective in Methylation

Presenter: Calvin Summers

Mentor: Eric Selker

Poster: 31

Major: Biology

Cytosine methylation, a fundamental form of epigenetic regulation, is found in many eukaryotes and plays a significant role in cancer and other diseases. Using the genetically tractable model organism Neurospora crassa, the Selker laboratory has identified genes that when mutated, cause the strains to be defective in methylation (dim). The process of DNA methylation in Neurospora has been shown to be dependent on DCDC, a five member complex that directs the histone methyltransferase DIM-5 to trimethylate Lysine 9 on histone H3 (H3K9me3). This mark is recognized by HP1, which directs DIM-2 to methylate DNA. Another silencing complex, HCHC, employs HDA-1, CDP-2, HP1, and CHAP to deacetylate lysines on the histone. While we know a good deal about DNA methylation, it is still unclear whether we have identified all genes involved in the process. Thus this research focuses on our search for dim mutants, and asks whether our current model for DNA methylation is saturated. Using a selection for reactivation of resistance genes silenced by DNA methylation we aimed to answer this question. Interestingly, we predominantly identified known dim genes, including dim-5, dim-7, dim-8, dim-9, chap, cdp-2, and hda-1, suggesting our model may be saturated. We localized mutations in these known dim genes by DNA sequencing. The dim mutant collection generated should be a useful resource for further investigation into the roles of these genes and their protein products in DNA methylation. Understanding epigenetic pathways in Neurospora is an auspicious first step in elucidating mechanisms of complex genetic regulation in our own cells.

The Effect of Chronic Passive Heat Therapy on Forearm Reactive Hyperemia

Presenter: Andrew Jeckell

Mentors: Christopher Minson and Vienna Brunt, Human Physiology

Poster: 31

Major: Post-baccalaureate 

Reactive hyperemia is a transient increase in blood flow that occurs following a period of ischemia (e.g. arterial occlusion) and is indicative of microvascular health. Regular exercise is a critical preventive measure in maintaining reactive hyperemia; however, consistent exercise is difficult or impossible for some people. Recent evidence suggests chronic passive heat therapy (CHT) may result in improvements to cardiovascular health similar to exercise. To examine the effects of 8 weeks of CHT on forearm post-occlusive reactive hyperemia, six healthy university students (21 ± 1 years) underwent hot water immersion 4-5 times per week to maintained rectal temperature of 38.5°C
for 1 hour per session. Before and after 8 weeks of CHT, brachial artery blood flow was measured via Doppler ultrasonography for 3 minutes following a 5-minute forearm arterial occlusion. Data presented as mean ± SE vascular conductance (VC, blood flow divided by mean arterial pressure). In preliminary subjects, change in peak VC from baseline, indicating structural microvascular changes, increased following CHT from 1.77 ± 0.24 to 2.26 ± 0.20 ml/ min/mmHg (p = 0.09). Area-under-the-curve of the hyperemic response, indicating functional changes, increased from 59.7 ± 9.0 to 111.9 ± 13.0 sec.ml/min/mmHg (p = 0.11). CHT appears to produce structural and functional microvasculature changes comparable to that of exercise, and could potentially serve as an alternative method for improving cardiovascular health.

Pileup Suppression in the ATLAS Detector

Presenter: Elliot Parrish

Faculty Mentor: Stephanie Majewski

Presentation Type: Poster 31

Primary Research Area: Science

Major: Physics

The ATLAS experiment at the Large Hadron Collider at CERN is looking to improve on their previous discovery of the Higgs boson in 2012 with the discovery of new particles. To ensure the continued success of ATLAS, there are a series of planned upgrades to the detector. After the Phase II upgrade, scheduled for 2026, the ATLAS detector will receive collisions of proton bunches every 25 ns with an average of 140 interactions per collision. Most of these interactions are not energetic enough to produce interesting physics (high energy events). The uninteresting interactions are referred to as pileup. These pileup interactions happen simultaneously with the interesting events, leading to a masking of the signal beneath the pileup. In order to sift through the large amounts of data, a firm understanding of pileup is needed. The focus of this study is to measure the energy deposited in the detector due to pileup and use it as a discriminating factor in reducing the data flow to a rate that can be written out in the time allotted.

Cortical Thickness: An Introduction and Comprehensive Review of the Current Literature

Presenter(s): Ha Eun Kim − Psychology

Faculty Mentor(s): Don Tucher, Ariel Wightman

Poster 31

Research Area: Neuroscience

Cortical thickness of the cerebral cortex provides valuable information about normal and abnormal brain anatomy. For the past 30 years, much research and studies have revealed the association of cortical thickness and various neurodevelopmental disorders as well as regional differences in normal brain function. In light of this research, it is crucial to understand and summarize what has been discovered so far. The aim of this review was to examine all available published cortical thickness research on Google Scholar and to provide a comprehensive summary of current studies. The literature search encompassed all relevant cortical thickness studies published until January 2017 on Google Scholar. Through several inspections, initially found 134 papers were narrowed down to 119 papers. The papers were inspected twice and were categorized into five different groups according to the paper’s relevant topics in terms of cortical thickness as follows: I, brief summary of the different cortical thickness extraction mechanisms; II, studies in healthy normal participants; III, studies in neurodevelopmental disorders; IV, studies in neuropathological disorders and V, studies in all other disorders. Summaries of research on more specific disorders were addressed in each subcategory. These outcomes indicate the importance of cortical thickness research and need for further analysis in the future.

Reliability and accuracy of post-mortem methods of manual 2D:4D assessment in primates Kendall Soriano, Sarah Brown, Enrique Gomez, Colin M. Brand, Frances J. White

Presenter(s): Kendall Soriano

Co Presenter(s): Sarah Brown

Faculty Mentor(s): Frances White & Colin Brand

Poster 31

Session: Sciences

The ratio of the length of the second to the fourth digitis[AH1] related to levels of prenatal hormone in exposure, specifically testosterone. A lower 2D:4D ratio indicates higher levels of prenatal androgen exposure, and a higher ratio indicates lower levels. Digit length is typically measured from the proximal crease to the most distal end of the digit in living and post-mortem individuals. However, post-mortem processes such as desiccation or decomposition can affect both landmark identification and accuracy of the measure. Digit length can also be measured on osteological specimens, but there is little information on how these measures compare to post- mortem measures. This study compares post-mortem measurements with osteological measurements taken on the same specimens. Here, we compared these measures across multiple primate species (N=40. We also examined the 2D:4D ratio in a macaque foot. First, using a caliper, measurements of the 3 segments in each digit were taken of a fully fleshed foot. Then, after removal of skin and flesh, measurements were taken of bones and tendons. Lastly, measurements of only bones were recorded after removal of tendons. This technique was shown to be an effective way of analyzing digit measurements as the results indicate clear differences in the ratio of digit sizes. This study demonstrates that the disarticulated measurement is the most accurate osteological method of estimating post-mortem 2D:4D. We want to take our knowledge of the relation between 2D:4D ratio and prenatal hormone exposure and apply it to across various other primate species.