Other Neuroscience and Neurobiology Commons^™

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

Sodium Channel Distribution In The Apical Dendrites Of Pyramidal Cells Vary In The Hindbrain Of Apteronotus Leptorhynchus., Sree Indrani Motipally

Graduate Theses, Dissertations, and Problem Reports (ETD)

Apteronotid weakly electric fish heavily rely on their electrosensory system for behaviors like spatial navigation, communication and prey capture. Since the behaviorally important information about their environment is contained in the spatial and temporal modulations of the electrosensory signal, efficient mechanisms to process this information with great fidelity are of the utmost importance. Efficient sensory processing often involves having multiple parallel processing streams so that each stream can specialize to treat signals with different properties. This strategy requires the response properties and neural dynamic to be adjusted in each pathway to implement different neural coding strategies. One of the neural …

Discrimination And Behavioral Responses To Communication Signals Compared Across Apteronotids., Danielle Leigh Dillon-Seeger

Graduate Theses, Dissertations, and Problem Reports (ETD)

Sensory systems are often uniquely tailored to encode behaviorally relevant signals and comparative studies across species can thus reveal how evolutionary changes shape sensory functions. The structure of communication signals varies widely between ghost knifefish species. Recent findings suggest that the nervous system co-adapted to the various signal structures observed across species to support different sensory behaviors. The aim for this thesis was to compare the sensory behavior of 3 species of ghost knifefish to contrast their behavioral performance with the known differences in neurophysiology. We hypothesize that for the different signal types and species, the ability to discriminate small …

The Role Of Mindfulness In Self-View Investment: Neural And Subjective Indicators, Hadley Rahrig

Theses and Dissertations

Self-concept is strongly influenced by beliefs about one’s personal psychological attributes, and these beliefs are held with varying degrees of confidence and consequence. Hence, it is investment in self-views of those attributes that helps to regulate and maintain stable self-concept. Self-view investment is relevant to numerous self-related functions, but high self-view investment can also contribute to maladaptive self-views. Theory suggests that mindfulness cultivates a less personal, more objective perception of one’s thoughts, emotions and behaviors, and training in mindfulness has been shown to alter self-referential processing. The current pilot study (N=21) investigates the possible role of dispositional mindfulness in two …

Illumination Of The Golgi Apparatus Of Pathogenic And Nonpathogenic Naegleria Species, Tyler M. Poe

Theses and Dissertations

In this study, Naegleria fowleri, a pathogenic amoeba and the causative agent of Primary Amebic Meningoencephalitis (PAM), was utilized to determine the presence or absence of classically conserved Golgi molecules featured in the expression of a Golgi apparatus. Previous studies concluded no Golgi expression via light microscopy and transmission electron microscopy, but a recent report on Naegleria gruberi indicated the presence of dispersed Golgi tubules. Non-pathogenic species of the Naegleria genus such as Naegleria gruberi 30540 and Naegleria lovaniensis 30569 were utilized in Western immunoblot analysis compared to reduced whole-cell lysate proteins of two strains of N. fowleri and …

The Progression Of Aβ Proteins In The Retrosplenial Cortex Using An App/Ps1 Alzheimer’S Disease Transgenic Rodent Model, Maha H. Rashid

Senior Independent Study Theses

Alzheimer’s disease is the most common form of dementia in the world with a new case of dementia diagnosed every 3.2 seconds. For over 25 years the amyloid cascade hypothesis has existed as a mechanism of understanding and diagnosing Alzheimer’s Disease. The amyloid cascade hypothesis suggests that Alzheimer’s Disease is sequential in protein progression and proliferative from the medial temporal lobe to the rest of the brain. Hypometabolism of brain regions has also been correlated to plaque deposition and hypometabolism is observed in brain regions that make up the default mode network, specifically the retrosplenial cortex, which is not accounted …

The Invisible Brain Injury Crisis, Michael E. Rosenthal

Capstones

According to the Center for Disease Control and Prevention’s 2013 data, over 282,000 hospitalizations and 2.5 million emergency department visits were at least in part attributable to TBI. In the same year, about 56,000 people died.

Emergency departments in 2012 treated about 329,290 kids under 20 for TBI following an injury taking place during physical activity.

This project explores the rise in traumatic brain injuries and examines the difficult path that some of the survivors have to go through during recovery. By telling the story through my own personal experiences, I guide the reader through what the initial trauma and …

The Opposing Roles Of Glun2c And Glun2d Nmda Receptor Subunits In Modulating Neuronal Oscillations, Zhihao Mao

Theses & Dissertations

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ion channels consisting of two GluN1 subunits and two other subunits from among GluN2A-2D and GluN3A-3B subunits. NMDARs play critical roles in synaptic plasticity, learning and memory, and higher brain function such as cognition and perception. Dysfunction of NMDARs (hyper-function and hypo-function of NMDARs) are related to various diseases, including stroke, schizophrenia, Alzheimer’s disease, and others. However, to date, NMDARs antagonists have mostly failed in clinical trials due to adverse effects.

NMDARs antagonists replicate the core symptoms of schizophrenia which may underlie its ability to alter neuronal oscillations in the neural circuitry of different brain …

Examining Delayed Onset Of Dementia In The Bilingual Geriatric Population, Erica Brown, Elizabeth Hartman

Grace Peterson Nursing Research Colloquium

Background: Dementia is the largest cause of dependency and disability in older adults, affecting nearly 50 million people worldwide with about 10 million new cases every year. Presently, there are no cures for dementia. Consequently, a growing body of evidence suggests that bilingualism may delay the onset of clinical dementia symptoms by several years.

Objectives: The purpose of this review is to summarize and analyze current evidence from studies that examined how bilingualism delays the onset of dementia. Evidence is reviewed suggesting that bilingualism may delay the dementia symptoms due to an increase in cognitive reserve, which refers to an …

Targeting Pro-Inflammatory Function Of Microglia Using Small Molecules To Combat Neurodegeneration, Gabrielle C. Williams, Priya Prakash, Gaurav Chopra

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microglia are the brain’s resident immune cells that are responsible for maintaining homeostasis in healthy conditions. During injury or infection, resting microglia get activated and produce pro-inflammatory cytokines such as IL-1b, IL-1a, IL-6, etc. along with reactive oxygen species like nitric oxide (NO) to combat neuroinflammatory diseases such as Alzheimer’s disease (AD). Inflammation is characterized by the activation of resident-immune cells in the brain called microglia that respond to the eat-me signals released by the toxic amyloid beta peptides as well as the dying neurons in the microenvironment. Recent studies have shown that activated microglia induce neuronal death by secreting …

Neural Coding Of An Auditory Pitch Illusion, Maria Alejandra Barrera, Mark Sayles, Ravinderjit Singh

The Summer Undergraduate Research Fellowship (SURF) Symposium

Pitch is an important perceptual dimension in audition, supporting auditory object segregation, melody recognition and lexical distinction. Huggins’ pitch, for example, is a phenomenon evoked by two sources of broadband noise presented binaurally with an inter-aural phase shift over a narrow frequency band. Huggins’ pitch and other dichotic pitches have been studied extensively using perceptual experiments. Several models have been proposed to explain and predict the perception of pitch; however, no studies have tried to record in vivo neuron responses to Huggins’ pitch (HP) nor have tried to explain how the HP is coded by neurons. The existence of pitches …

Characterization Of Theranostic Peptides For Glioblastoma Multiforme, Aaron Mellesmoen

All NMU Master's Theses

Glioblastoma multiforme (GBM) is a type of primary CNS tumor in which viable treatment options do not exist. Standard of care including tumor resection, chemotherapy, and radiation does little to extend the 5-year survival expectancy past 5.1%. Herein, two small-peptide molecules with inherent antitumor activity, blood-brain barrier permeability, and capability for tumor-specific drug deliverance and intraoperative visualization (termed theranostic) were of focus. Confocal microscopy was employed to characterize in vitro specificity of chlorotoxin, a 4 kDa scorpion venom peptide, and rBSG, the recombinant 25 kDa non-glycosylated extracellular domain of extracellular matrix metalloproteinase inducer (EMMPRIN; Basigin) isoform …

Ube4b Levels Determine The Efficacy Of Egfr And Stat5 Inhibitors In Treatment Resistant Neuroblastoma, David James Savage

Dissertations and Theses (Open Access)

Neuroblastoma is the most common malignancy in infants. Overexpression of the epidermal growth factor receptor (EGFR) in neuroblastoma tumors can result in enhanced EGFR signaling, uncontrolled proliferation, and may provide a mechanism for chemotherapy resistance. UBE4B, an E3/E4 ubiquitin ligase, ubiquitinates the EGFR and promotes its lysosomal degradation ultimately attenuating EGFR signaling. Interestingly, the UBE4B gene lies in a chromosomal region (1p36) whose loss is correlated with poor patient outcomes due to inefficient EGFR degradation and enhanced cell proliferation. We examined whether depletion of UBE4B in a chemoresistant neuroblastoma cell line would affect tumor responses to drugs that specifically target …

Modeling And Mapping Addiction In The Zebrafish, Danio Rerio, Bradley Serpa

Master of Science in Integrative Biology Theses

Driven by the communication of dopamine, the vertebrate reward system has been evolutionarily conserved to maintain survival and optimize fitness. The neural circuits governing this system integrate sensory stimuli to produce appropriate, self-preserving responses that underlie experience-based learning. In the most primitive vertebrates, dopamine release in neuronal circuits drives homeostatic behaviors, such as seeking nutrients, finding a mate, or avoiding danger. From agnathans to mammals, dopaminergic synthesis and signaling genes and molecules, along with neuronal pathways and reward system-based behaviors, remain highly conserved. Dopamine signaling proteins include two classes of metabotropic G-Protein Receptor Coupled Dopamine Receptors, D1-like (DRD1) and D2-like …

Complexities And Challenges Of Nonduality, Elizabeth Stephens

CONSCIOUSNESS: Ideas and Research for the Twenty-First Century

States of consciousness referred to as nonduality, awakening, enlightenment, moksha, peak experience, unitive states, or void states, among other terms, have garnered increasing secular attention and have become a topic of psychological and neuroscientific research. A review of the literature revealed many challenges to studying this set of states, such as inconsistent conceptualizations, a variety of models and theories, and conflicting descriptions indicating that the actual experience may not live up to the superlative descriptions found in historical texts or the expectations put forth by nondual teachers. A great deal more empirical research on this topic is needed, and researchers …

Regulation Of Epithelial Sodium Channels In Vasopressin Neurons In The Hypothalamus, Natalie Jean Mills

LSU Doctoral Dissertations

Salt-sensitive individuals have blood pressure that is unusually sensitive to salt intake. Because salt-sensitivity is a common disorder and may cause high blood pressure, it is a significant public health concern. All three epithelial Na⁺ channel (ENaC) subunits (a, b, and g) and the mineralocorticoid receptor (MR), a known regulator of ENaC, are expressed by vasopressin (VP) synthesizing magnocellular neurons in the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei. A growing body of evidence indicates that epithelial Na⁺ channels (ENaCs) in the hypothalamus play a significant role in the development of salt-sensitivity. My dissertation research tests the hypothesis …

Chemosensory Communication And Neural Substrates Of Social Behavior In The African Cichlid Fish, Astatotilapia Burtoni, Karen Elizabeth Field

LSU Doctoral Dissertations

Social animals must constantly assess their environment to make appropriate decisions. In several fish species, chemosensory signaling is crucial for social communication, conveying information on sex, reproductive state, and social status. Despite its importance in fishes, relatively little is known about how they employ chemical signaling, with only a few of the over 30,000 extant species investigated thus far. Further, there is a scarcity of information about where and how socially-relevant chemosensory signals are processed in the brain of fishes, or how chemosensory signals are integrated with other senses to elicit appropriate behaviors. For my doctoral research, I examined the …

Endocytosis And The Nitric Oxide-Dependent Release Of Chloride, Vernon K. Dunn Jr

LSU Doctoral Dissertations

Understanding the regulation of retinal synapses is a key step in elucidating the processing of information in the retina. Our lab has previously shown that nitric oxide (NO) can alter the synaptic response properties of amacrine cells by releasing Cl- from internal acidic compartments. This alteration in the Cl- gradient brings about a positive shift in the reversal potential of the GABA-gated current, which can convert inhibitory synapses into excitatory synapses. Recently, we have shown that the cystic fibrosis transmembrane regulator (CFTR) Cl- channel is involved in the Cl- release. Here, we test the hypothesis that (acidic) synaptic vesicles are …

Effect Sizes In Task-Based Functional Magnetic Resonance Imaging, Tyler Kellett

Celebration of Learning

Task-based functional magnetic resonance imaging (t-fMRI) techniques have changed the way scientists probe the neurological mechanisms underlying behavior. However, there are many problems surrounding t-fMRI especially underpowered studies leading to misleading effect sizes. This study is using a recent large data collection study, the Human Connectome Project, to investigate effect sizes in specific regions of the brain involving working memory. Previous studies have come up with relatively small effect sizes due to small sample sizes and large regions of interest (ROI). This study is concentrated on using more precise ROI called parcels to find larger effect sizes.

The Ush2a Gene: An Analysis Of Ultrasonic Vocalizations In A Mouse Model Of Usher Syndrome Type 2, Kiana R. Akhundzadeh

Honors Scholar Theses

Usher syndrome type 2 is a complex autosomal recessive genetic disorder that is characterized by moderate to severe congenital sensorineural hearing loss, the onset of retinitis pigmentosa in the second decade of life, and in some cases, vestibular dysfunction. Mutations in the USH2A gene account for 85% of cases of type 2. The USH2A gene is responsible for encoding the protein usherin, which has an important role in the development and function of inner ear hair cells and retinal photoreceptors. Until recently, it has been believed that carriers of the USH2A mutation were phenotype free. However, recent data has suggested …