Medical Neurobiology Commons^™

Oral Streptococcus And Vitamin B12 Deficiency In E-Cigarette Users: A Microbial–Nutrient–Neurotransmitter Axis Linking To Mood Disturbances, Maryam Sabah Naser, Ali Jabbar Abd Al-Hussain Alkawaz, Ali Abbas Hashim Almusawi, Ali Jalil Obaid, Hasanain Ayed Mohammed Al-Khafaji, Reihaneh Sabbaghzadeh

Karbala International Journal of Modern Science

Background: With the rising popularity of e-cigarettes, questions have emerged regarding their broader influence on oral ecology, nutrient absorption, and psychological health. Disruptions in the oral microbiome may alter vitamin B12 dynamics. This, in turn, may indirectly influence serotonin biosynthesis and mood regulation.

Methods: An observational cross-sectional study involved 150 young adults segregated into groups of 50 each as vapers, smokers, or non-users. Streptococcus sanguinis and vitamin B12 metabolism-related variable statuses methylmalonic acid and holotranscobalamin were quantified in samples, along with inflammatory markers interleukin-6, kynurenine/tryptophan ratio, and serotonin. Statistical techniques, including ANOVA and the Kruskal-Walli’s test, correlation, and serial mediation …

Silver Nanoparticle-Induced Disruption Of Astrocytic Morphology And Synaptic Microarchitecture In Rat Brain, Elli Williams

Theses, Dissertations and Capstones

Silver nanoparticles (AgNPs) are widely incorporated into consumer and medical products due to their antibacterial properties, increasing the potential for chronic exposure. AgNPs can be released into the environment, enter the body through ingestion or inhalation, cross the blood-brain barrier (BBB), and bioaccumulate in brain tissue. Previous in vitro studies demonstrate that AgNP exposure disrupts cytoskeletal organization and induces neurite collapse in neural cells, suggesting vulnerability of cytoskeleton-dependent structures in vivo. Astrocytes, through their perisynaptic astrocytic processes (PAPs) and perivascular endfeet, play critical roles in maintaining synaptic and neurovascular architecture, both of which rely heavily on cytoskeletal integrity. This …

Dose-Dependent Developmental Toxicity Of Cisplatin In Zebrafish Embryos, Reagan D. Sellers, Katherine T. Doucet, Jinhee Park, Andrea Florian

SPARK Symposium Presentations

Cisplatin is a widely used chemotherapy drug for treating various types of cancer. Although cisplatin is effective in killing cancer, it can also cause toxic side effects in normal tissues. Because cisplatin can cross the placental barrier, its use during pregnancy is generally avoided, particularly during early embryonic stages of fetal development. Exposure to cytotoxic drugs during embryogenesis may lead to developmental abnormalities, birth defects, or pregnancy complications. Understanding how cisplatin affects early development is therefore important.          
       Zebrafish (Danio rerio) are an established model for studying developmental toxicity due to their rapid external development, transparent embryos, and genetic similarity to …

The Effects Of Stress-Related Hormones On Excitatory Synapse Formation, Autumn C. Garvey

Honors Undergraduate Theses

Stress profoundly influences brain function through neuromodulatory hormones that regulate synaptic plasticity, yet how temporal patterns of hormone exposure shape excitatory synapse formation remains poorly understood. This study investigates how exposure to stress hormones, norepinephrine and cortisol, affects excitatory synapse development. While existing research primarily compares concentration models, real-world stress occurs in variable patterns that may produce distinct neural outcomes. To address this gap, differentiated Neuro2A neuronal cells are exposed to norepinephrine or cortisol under a continuous treatment paradigm designed to model chronic stress conditions. Following treatment, immunofluorescence imaging is utilized to quantify excitatory synapse formation through analysis of presynaptic …

Exploring Anticholinergic Neurotoxicity: Diphenhydramine's Impact On Neuro-2a Cell Morphology, Expression, And Viability, Jordan B. Mcintyre

Honors Undergraduate Theses

Anticholinergic medications, such as diphenhydramine (commonly known as Benadryl), are increasingly recognized for their association with cognitive impairment and neurodegenerative disease. These medications, which inhibit the action of acetylcholine, a neurotransmitter essential for the formation and utilization of the central and peripheral nervous system, have been implicated in conditions such as dementia and may impact fundamental cellular processes like neurogenesis and cell proliferation. This study investigates the effects of diphenhydramine on neurogenesis when introduced to Neuro-2a cells during differentiation. For all studies cells were plated on coverslips or in 6-well plates with differentiation media containing 0 ng/mL, 50 ng/mL, …

Manuka Honey Modulates Oxidative Stress In Neuro2-A Cells Through Mitochondrial Regulation, Rachel Abramovici

Honors Undergraduate Theses

Manuka honey is known for its vital usage in wound healing, being an agonist towards fighting infections, and is an acting antioxidant [32]. Its main constituents are flavonoids and phenolic compounds, with methyl syringate (MSYR) being a major active ingredient. The specific compounds responsible for these antioxidant effects, particularly in the CNS, remain unclear. It is hypothesized that pre-treatment of mouse neuroblastoma cells with MSYR followed by hydrogen peroxide exposure will activate the AMPK/SIRT1/PGC-1a pathway, due to MSYR’s phenolic structure, and thus reduce oxidative stress and improve mitochondrial biogenesis. Hydrogen peroxide is a standard reactive oxygen species (ROS) treatment to …

Stat4-Dependent Regulation Of Neuroinflammation In Atherosclerosis, Natalie Stahr, Alina K. Moriarty, Shelby D. Ma, W. Coles Keeter, Woong-Ki Kim, Larry D. Sanford, Elena V. Galkina

Department of Biomedical and Translational Sciences Faculty Publications

Atherosclerosis is linked to an increased risk of cognitive decline, with chronic inflammation being a common feature of both pathologies. IL-12 activates STAT4 to regulate myeloid cell functions, and blockade of this pathway alleviates cognitive impairment in Alzheimer's models. However, the mechanisms connecting vascular pathology to neuroinflammation remain unclear. Here, we examine whether STAT4 functions as a common mediator of neuroinflammation in atherosclerosis. We demonstrate that LysM^Cre-specific STAT4 deficiency ameliorates deficits in long-term memory in low-density lipoprotein-deficient (Ldlr^-/-) mice fed a high-fat diet (HFD-C). STAT4 deficiency moderately reduces Ser199-phosphorylated Tau burden. Atherosclerosis alters brain immune …

Abnormalities In Sensorimotor Brain Function Are Related To Chronicity Of Low Back Pain, Jo Armour Smith, Rongwen Tain, Kelli G. Sharp, Laura M. Glynn, Linda R. Van Dillen, Jesse V. Jacobs, Steven C. Cramer

Physical Therapy Faculty Articles and Research

Maladaptive plasticity in the brain may contribute to chronic low back pain (LBP) and underlie the altered postural control of the lumbopelvic musculature that is evident in some individuals with LBP. We recently described an MRI-compatible leg-raise paradigm to measure brain activity associated with lumbopelvic postural control. The objective of this study was to compare brain function in young adults with and without a history of LBP and to determine relationships between brain function, pain, and postural control characteristics. We recruited 55 participants with a history of LBP, who were asymptomatic when studied, and 30 healthy controls. Postural control during …

Acute And Chronic Effects Of Neuroinflammation On Hippocampus And Anterior Cingulate Cortex Network Dynamics, Lauren A. Crew

UNLV Theses, Dissertations, Professional Papers, and Capstones

Neuroinflammation has emerged as a critical modulator of cognitive function and neural circuit dynamics, yet the distinct contributions of acute and chronic neuroinflammation to brain function remain poorly defined. This dissertation examines how inflammation independently alters large-scale neural activity and behavior, focusing on interactions between the hippocampus (HPC) and anterior cingulate cortex (ACC), regions essential for memory and executive processes. Using in vivo electrophysiological techniques in a rodent model, this study compares the effects of short-term (acute) and prolonged (chronic) neuroinflammatory states, induced via Poly I:C, on neural oscillations, regional coherence, and spatial coding. Findings reveal that even transient inflammation …

T Cell Senescence And Nociplastic Pain: A Proposed Etiological Mechanism, Kayla S. Riggleman

Senior Honors Theses

Nociplastic pain is a newly identified chronic pain phenotype characterized by widespread hyperalgesia and allodynia. Its etiological mechanisms are currently unknown, making medical intervention elusive. The proposed pathophysiological model connects immunosenescence with a degradation of the blood-brain barrier as a result of peripheral inflammation. Neuronal hyperexcitability and glial cell activation result, leading to nociplastic pain. It is currently thought that central sensitization is the key mechanistic driver of nociplastic pain, so this literature review seeks to expound on that. Based on this framework, chimeric antigen receptor (CAR)-T cell therapy and stem cell treatments are proposed therapeutic methodologies to be explored. …

Perceptions And Attitudes On Biospecimen Sample Collection For Dementia Research In Kenya, Lucy Kamau, Chinedu Momoh, Karen Blackmon, Caroline Kiio, Jasmit Shah, Vaibhav Narayan, Irene Meier, Olivera Nesic Taylor,, Zul Merali, Edna Bosire

Brain and Mind Institute

Background: Biospecimen sample collection is crucial in dementia diagnosis and evaluation. Limited research exists from African Countries including Kenya on people's perception on biospecimen sample collection for dementia- a disease that is largely unknown. Our aim was to understand the public perceptions towards collection of biospecimen samples for dementia research in Kenya.

Method: We conducted 8 focused group discussions (FGDs; age and gender stratified) in Nairobi to understand people's perceptions about different biospecimens (urine, saliva, blood, tears, hair, cerebrospinal fluid (CSF) and the brain samples). An open-ended FGD guide was used for the discussions, each lasting about 90 minutes.

Result: …

Dual-Task Interaction Between Vestibular Function And Cognitive Processing Using The P300 Event-Related Potential, Laurel Elise Money-Nolan

Graduate Theses and Dissertations (2019 - present)

Previous research has established links between vestibular function and cognitive processing, aging and cognitive function, and aging and vestibular function. Theories of cognitive resource allocation discuss how cognitive resources, such as attention, are devoted towards and divided between tasks when multitasking. This dual-task study, utilizing a balance task and a listening/cognitive task, across the young- and middle-aged adult age range, aimed to evaluate potential relationships between vestibular function, cognition, and age, and to examine how cognitive resources might be allocated under dual-task conditions.

The dual-task protocol in this study utilized an oddball paradigm with tonal stimuli to measure the P300 …

Dietary Fiber Modulates Gut Microbiota And Lipid Metabolism Ameliorating Alzheimer's Pathology In 5xfad Mice, Yuhai Zhao, Christopher M. Taylor, Walter J. Lukiw, Nicolas G. Bazan

School of Graduate Studies Faculty Publications

The gut-brain axis plays a critical role in maintaining neuronal integrity and influencing the progression of Alzheimer's disease (AD). Here, we investigated how commonly consumed dietary fibers modulate gut microbiota, lipid metabolism, and AD pathology in 5xFAD mice. Male mice were fed either fiber-free (FF) or fiber-plus (FP; 1% cellulose, 2% pectin, 2% inulin) diets for five months, followed by integrated analyses of gut microbiota (16 S rRNA sequencing), fecal lipid metabolites (LC-MS/MS), and neuropathological and behavioral outcomes. FP diets markedly altered microbial composition, characterized by increases in Muribaculaceae, Ileibacterium, and Lachnospiraceae NK4A136 group and reductions in Faecalibaculum and Coriobacteriaceae …

Mechanisms Of Correlated Neuronal Activity In The Globus Pallidus, Hamza Albawaliz

Electronic Theses and Dissertations

This thesis investigates the mechanisms of correlated neuronal activity in the globus pallidus externus (GPe), a key structure in the basal ganglia. Neuronal activity in the GPe is reportedly decorrelated in healthy subjects but can become highly correlated in Parkinson’s disease. However, high-density neuronal recordings in the GPe of healthy rats reveal a surprising degree of correlated activity. This raises the question of whether intrinsic properties or network connectivity alone can account for such patterns. To explore this, a computational model was developed in which GPe neurons are represented as coupled phase oscillators influenced by experimentally derived phase-response curves and …

Cerebral Malaria In Chad- A Case Report Series, Megan W. Szobody, Blaise Djomg Yang, Noel Johnson, Kelsey Potter-Baker

Research Colloquium

Malaria is a serious disease caused by various species of the Plasmodium genus. Among these, Plasmodium falciparum is widely considered the most dangerous, due to its ability to infect both young and mature red blood cells (RBCs). Malarial disease, caused primarily by P. falciparum, is a major cause of morbidity and mortality in Sub-Saharan Africa, and notably in Chad, accounting for over 10,000 deaths each year and with an incidence rate of over 3 million. Anyone can acquire falciparum malaria after being bitten by infected anopheles mosquitoes, but in pregnant women and young children, this disease is often deadly. A …

Determining The Effects Of An Hiv Infective Model On The Development Of Neuropathic Pain In Alzheimer’S Disease Model Mice., Ayesha Usman, Megan W. Szobody, Jose Rios, Mohammed Alnoud, Khalid Benamar

Research Colloquium

The purpose of this study is to determine the effect of the Human Immunodeficiency virus (HIV) in producing neuropathic pain in an Alzheimer’s Disease (AD) mouse model. HIV-1 envelope glycoprotein gp120 is correlated with increased release of thermal hyperalgesia and mechanical allodynia mediators from astrocytes and glial cells in rodents, producing the identifiable symptoms of neuropathic pain. Similarly, studies show that 45.8% of AD patients experience chronic pain. The production of an HIV/AD comorbid mouse model will be useful in determining important pathological pathways for neuropathic pain and is vital to future studies in therapeutic approaches to these conditions. Two …

Corticobasal Syndrome With Mixed Pathology In The Absence Of Grn Mutation: A Clinico-Pathological Case Of Ftld-Tdp With Coexisting Alzheimer’S And Lewy Body Pathology, Hugo Zamarron, David Irwin, Jeffery Phillips, Edward Lee, Matthew Tisdall, Corey Mcmillan

Research Colloquium

Background: Corticobasal syndrome (CBS) is a neurodegenerative disorder characterized by often asymmetric fronto-pariteal and extra-pyramidal features that is traditionally associated with tauopathy, but pathological findings are heterogenous, including other forms of frontotemporal lobar degeneration (FTLD) and mixed pathologies of aging. We present clinical, radiographic, and histopathologic features of asymmetry in a unique patient with CBS and underlying FTLD with TDP-43 pathology (FTLD-TDP), co-occurring with other age-related pathologies.

Case Presentation: A 76-year-old man presented with progressive cognitive and motor dysfunction including asymmetric parkinsonism, left-sided dystonia and rigidity, apraxia, visuospatial impairment, and a subtle social disorder including apathy and social withdrawal. The …

Transcriptomic And Epigenomic Profiling Of Immune Cells Responses To Simian Immunodeficiency Virus Infection In The Brain, Xiaoke Xu

Theses & Dissertations

Human immunodeficiency virus type 1 (HIV-1) is an enveloped retrovirus that significantly impairs the human immune system. A common complication of HIV-1 infection is HIV-associated neurocognitive disorder (HAND), which, prior to the introduction of antiretroviral therapy (ART), led to considerable morbidity and mortality due to untreated neuropsychiatric manifestations. Although ART has substantially reduced the incidence of HIV-associated dementia (HAD), approximately 50% of people living with HIV (PLWH) continue to experience milder forms of HAND. The CNS is seeded by HIV during the acute phase of infection. Once in the brain, HIV targets and activates resident immune cells, primarily microglia and …

The Speech-To-Song Illusion Across Development And The Effects Of High-Level Expectations, Rodica R. Constantine

UNLV Theses, Dissertations, Professional Papers, and Capstones

The typical listener can readily categorize auditory stimuli as either speech or song even though these structures share many acoustic similarities. These musical and linguistic categories may nevertheless take time to develop as children acquire language- and music-specific knowledge. In the Speech-to-Song (STS) illusion, multiple repetitions of a natural spoken utterance can give rise to a perceptual switch wherein the stimulus begins to sound song-like to the listener. While the STS illusion has been well-researched in adult listeners, it had yet to be investigated in children. In our study, we examined whether children experience the STS illusion by presenting participants …

Exploring The Processing Of Objects, Settings, And Global Properties In Natural Auditory Scenes, Margaret A. Mcmullin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Our auditory system has a remarkable ability to make sense of complex environments, allowing us to identify what we are hearing and where sounds come from. This process of auditory scene analysis is essential for situational awareness, decision-making, and effective communication in daily life. While much is known about how listeners segregate and identify individual sound sources (e.g., voices), less is understood about how global properties of a scene (e.g., openness, naturalness) contribute to perception. This dissertation examined how object- and setting-level information in natural auditory scenes are processed, and whether they rely on distinct or overlapping mechanisms. In Experiment …