Medicine and Health Sciences Commons^™

A Multimodal Approach To Investigate Brain Reorganization After Spinal Cord Injury Using Functional Magnetic Resonance Imaging And Functional Near-Infrared Spectroscopy, Keerthana Deepti Karunakaran

Dissertations

Traumatic Spinal Cord Injury (SCI) results in structural and functional neurological changes at both the brain and the level of the spinal cord. Anatomical studies indicate decreased grey matter volume in sensorimotor and non-sensorimotor regions of the cortex following SCI; whereas, neurophysiological findings mostly report altered functional activity in the sensorimotor nodes of the cortex, subcortex, and cerebellum. Therefore, it is currently unknown whether tissue atrophy observed in non-motor related areas has any concomitant functional consequences. Furthermore, the neural underpinnings of adaptive neuroplasticity after SCI is not well-defined in the current literature. Hence, this dissertation is a pioneer study investigating …

High-Performance Learning Systems Using Low-Precision Nanoscale Devices, Nandakumar Sasidharan Rajalekshmi

Dissertations

Brain-inspired computation promises a paradigm shift in information processing, both in terms of its parallel processing architecture and the ability to learn to tackle problems deemed unsolvable by traditional algorithmic approaches. The computational capability of the human brain is believed to stem from an interconnected network of 100 billion compute nodes (neurons) that interact with each other through approximately 10¹⁵ adjustable memory junctions (synapses). The conductance of synapses is modifiable allowing the network to learn and perform various cognitive functions. Artificial neural networks inspired by this architecture have demonstrated even super-human performance in many complex tasks.

Computational systems based …

Redefining Burnout: Exploring Common Conceptualizations And The Neurophysiology Of Chronic Stress To Establish An Integrated Allostatic Model, Danny A. Guzzi

Dissertations

Burnout is a widely researched stress-related phenomenon associated with numerous adverse outcomes for employees and organizations. Unfortunately, burnout is not well understood and research to this point has been flawed due to a lack of consensus on the definition, dimensionality, and context of the construct. Prevalent conceptualizations of burnout have been criticized for being arbitrarily developed without solid theoretical foundation and for failing to clearly distinguish burnout from depression or other work-related conditions such as compassion fatigue, secondary traumatization, and vicarious traumatization. The current project first examines relevant literature to identify commonalities among prevalent burnout conceptualizations. Then relevant stress research …

Submandibular Mechanical Stimulation Of Upper Airway Muscles To Treat Obstructive Sleep Apnea, Ferhat Erdogan

Dissertations

The extrinsic tongue muscles are activated in coordination with pharyngeal muscles to keep a patent airway during respiration in wakefulness and sleep. The activity of genioglossus, the primary tongue-protruding muscle playing an important role in this coordination, is known to be modulated by several reflex pathways mediated through the mechanoreceptors of the upper airways. The main objective is to investigate the effectiveness of activating these reflex pathways with mechanical stimulations, for the long-term goal of improving the upper airway patency during disordered breathing in sleep. The genioglossus response is examined during mandibular and sub-mandibular mechanical stimulations in healthy subjects during …

Mechanisms And Consequences Of Epigenetic Inheritance Following Parental Preconception Alcohol Exposure, Annadorothea Asimes

Dissertations

Recent advances in genomics research have revealed that preconception behaviors and experiences of mothers and fathers, including diet, environmental toxicants, and drug abuse, can impact future offspring through epigenetic mechanisms. This means that the risky behaviors of young people, such as the extremely popular practice of binge drinking, have potentially far-reaching consequences for generations to come. While there has been considerable research into fetal alcohol exposure and parental alcoholism, there has yet to be sufficient investigation into the mechanism of epigenetic inheritance or the functional consequences of parental preconception binge pattern alcohol abuse. The hypothesis tested herein is that parental …

Elevated Hydrostatic Pressure Selectively Enhances Matricellular Gene Expression In Human Trabecular Meshwork Cells, Jonathan Lautz

Dissertations

Primary open-angle glaucoma (POAG) is a progressive optic neuropathy

characterized by loss of peripheral vision secondarily associated with elevated intraocular pressure (IOP). Transforming growth factor (TGF)-β2 is markedly elevated in the aqueous humor (AH) of patients with POAG. It has been previously shown that TGF-β2 increases IOP, in part, by inducing expression and release of endothelin-1 (ET-1) and connective tissue growth factor (CTGF) within the trabecular meshwork (TM). ET-1 and CTGF may ultimately lead to increases in IOP by enhancing TM cell contractility and extracellular matrix (ECM) deposition. Here we confirm that TGF-β2 enhances mRNA content of ET-1, CTGF, and …

Examining The Effects Of Adolescent Binge Alcohol Exposure On The Negative Feedback Of The Hpa Axis And Adult Responses To Psychological Stress, Audrey Rose Torcaso

Dissertations

Binge drinking during adolescence is a common occurrence which is associated with increased risk of developing alcohol dependence and other mental health disorders. Hypothalamo-pituitary-adrenal (HPA) axis dysfunction is one characteristic commonly observed in many affective disorders, including anxiety and depression. Our laboratory has previously demonstrated that adolescent binge-pattern alcohol exposure results in long-term dysfunction of the HPA axis in a Wistar rat model, characterized by deficient glucocorticoid feedback inhibition. The current study aimed to characterize the behavioral phenotype of these rats in response to psychological stress during adulthood, and furthermore sought to understand the molecular mechanisms by which adolescent binge …

Examining The Effects Of Anti-Nogo A Immunotherapy On Post-Stroke Neurogenesis In The Adult Rat, Daniel Shepherd

Dissertations

Stroke is a leading cause of adult disability with no pharmacological treatments to restore lost function. Our laboratory has shown that treatment with neutralizing antibodies against the neurite growth-inhibitory protein Nogo-A improves sensorimotor and cognitive recovery after stroke in adult and aged rats. This recovery is paralleled by increased dendritic and axonal plasticity in anti-Nogo-A-treated rats. Neurogenesis, an alternate form of plasticity involving the de novo production of new neurons, may contribute to post-stroke neural repair. While previous studies have found roles for Nogo-A in adult neurogenesis, neurogenesis has not been investigated after stroke and anti-Nogo-A treatment. The goal of …

Consequences Of Estrogen Receptor Beta Phosphorylation In The Aged Female Brain And Heart, Elena Pinceti

Dissertations

Female life expectancy in the United States has steadily increased and now averages 81 years. Meanwhile, the age at which women reach menopause remains constant at 51 years. Both neurological and cardiovascular disorders increase following menopause, affecting women’s quality of life and leading to large health care costs. Estrogens are neuroprotective and cardioprotective for women, however when administered long after menopause, they fail to improve their health.

The effects of estrogen are mediated by Estrogen Receptor α (ERα) and Estrogen Receptor β (ERβ). Evidence supports that ERβ plays an important role in neuroprotection and cardioprotection, but aspects of ERβ molecular …

Effects Of Aggregated Alpha-Synuclein On Cultured Neuronal Cells, David Freeman

Dissertations

α-synuclein dysregulation is a critical aspect of Parkinson's disease pathology. Recent studies have observed that α-synuclein aggregates are cytotoxic to cells in culture and that this toxicity can be spread between cells. However, the molecular mechanisms governing this cytotoxicity and spread are poorly characterized. Recent studies of viruses and bacteria, which achieve their cytoplasmic entry by rupturing intracellular vesicles, have utilized the redistribution of galectin proteins as a tool to measure vesicle rupture by these organisms. Using this approach, we demonstrate that α-synuclein aggregates can induce the rupture of lysosomes following their endocytosis in neuronal cell lines. This rupture can …

Extended Treatment Window Exists For Improving Sensorimotor Recovery Using Anti-Nogo A Immunotherapy In Adult Rats With Chronic Stroke Deficits, Katherine Marie Podraza

Dissertations

Stroke related death ranks as the fourth most common cause of mortality in the United States. Current therapeutic options following stroke are limited. One potential therapy involves the use of anti-Nogo-A immunotherapy post-stroke. Our laboratory has shown that the administration of this novel treatment results in sensorimotor recovery in adult and aged rats. This therapy has been shown to be efficacious when applied immediately, 24 hours, and 1 week post-stroke in rats with mild to moderate sensorimotor deficits. In addition, recent results suggest that administration of anti-Nogo-A immunotherapy up to 9 weeks after stroke still induces functional recovery and neuroanatomical …

Peripubertal Binge Ethanol, Age And Sex Modulate Microrna Expression In The Ventral And Dorsal Hippocampus Of The Adolescent Rat, Sarah Arianne Prins

Dissertations

Adolescent binge ethanol (EtOH) abuse induces long-term changes in gene expression, resulting in an increased risk for the development of adult mood disorders. microRNAs (microRNAs) are small, noncoding RNAs that regulate gene expression by translational repression. microRNA altered in response to EtOH and puberty in the developing brain. The biogenesis of mature 22-24 nucleotide (nt), single-stranded microRNAs involves Drosha and Dicer enzymatic processing of microRNA precursors. A mature microRNA imperfectly base pairs with messenger RNA (mRNA) target genes,which leads to mRNA cleavage or translational repression. Our lab has found that repeated binge EtOH exposure alters gene expression in the hypothalamus …

Effects Of Electrical Stimulation And Testosterone In Translational Models Of Peripheral Nerve Injury, Gina Monaco

Dissertations

As functional recovery following peripheral nerve injury is dependent upon successful regeneration and target reconnection, combinatorial treatments that enhance different regeneration events may be required for recovery from severe injuries. The neurotherapeutic effects of electrical stimulation (ES) and gonadal steroids have been demonstrated independently and in combination in extratemporal and intratemporal facial nerve injuries. The goals of the first aim were to develop a reliable intracranial facial nerve crush model and to investigate the therapeutic potential of combining ES with testosterone propionate (TP) in this most proximal injury model. Adult male rats were divided into intracranial sham-operated, intracranial crush, and …

Binge Alcohol And Recovery After Traumatic Brain Injury, Ian Vaagenes

Dissertations

An estimated 275,000 Americans are hospitalized following a traumatic brain injury (TBI) every year, 80,000 of whom develop a long-term disability. The factor that places one at perhaps the greatest risk of suffering a TBI is alcohol intoxication. 30-50% of TBI sufferers have a blood alcohol level above .08 mg/dl at the time of injury, the legal limit in most U.S. states. In fact, the presence of alcohol at the time of TBI more than doubles the risk of a repeat head injury in the two years following the injury. Given the large population of TBI sufferers with alcohol intoxication …

Influence Of Pramipexole On Probability Discounting And Ventral Pallidal Function: Assessments In Parkinsonian-Like Rats, Sandra Lynn Rokosik-Kletzel

Dissertations

People with neuropathologies who are treated with dopamine agonists may be at risk to develop impulse control disorders. The overall goal of this dissertation project was to expand our knowledge on the neuropsychopharmacology of dopamine agonist-induced impulsivity. At the time this dissertation was being developed, pramipexole was the drug, gambling was the behavior, and Parkinson's disease (PD) was the pathology most widely reported for this phenomenon. Therefore, we first developed a behavioral paradigm (i.e., probability discounting) to measure risk-taking, one aspect of gambling. Utilizing this paradigm, we determine if risk-taking was altered after acute and/or chronic pramipexole treatment. We incorporated …

Statin-Mediated Attenuation Of Chemokine Expression In Peripheral Nerve Vascular Endothelial Cells, Kelly Ann Langert

Dissertations

Pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), play a pivotal role in the pathogenesis of Guillain-Barré Syndrome (GBS), a debilitating autoimmune disorder that affects the peripheral nervous system. By up-regulating endothelial expression of chemokines and cell adhesion molecules (CAMs), TNF-α facilitates the recruitment and trafficking of autoreactive leukocytes across the blood-nerve barrier and into peripheral nerves, an early pathological hallmark of GBS. Literature indicates that TNF-α, monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) are locally increased in patients with GBS, correlating with disease severity. Similar findings have been demonstrated in an animal model of GBS, experimental autoimmune neuritis …

Forebrain Noradrenergic Alterations And Anxiety After Myocardial Infarction, Jaimee Glasgow

Dissertations

Thirty to 45% of patients who suffer a myocardial infarction (MI) develop anxiety disorders and/or depression, and the development of mood and anxiety disorders following MI is a major risk factor for cardiovascular morbidity and mortality. Depressed post-MI patients have an increased risk of fatal arrhythmias, which are often precipitated by emotional stressors. However, the central nervous system mechanisms that contribute to post-MI anxiety and arrhythmia susceptibility are unknown. Therefore, the studies reported in this dissertation were designed to test the hypothesis that alterations in noradrenergic transmission in the forebrain contribute to the development of anxiety disorders and arrhythmia susceptibility …

Neurochemical Effects Of Amyloid-Beta Oligomers In Rats, John J. Panos

Dissertations

Alzheimer’s disease is a progressive neurodegenerative disease characterized by memory loss and cognitive decline. Although the symptomology of Alzheimer’s disease is well defined, its precise etiology remains elusive. Animal models are invaluable for understanding the pathogenesis of this devastating disease. Knowledge of the neurochemical actions of amyloid-β oligomers in specific brain structures is essential for validating animal models of Alzheimer’s disease and for determining the most appropriate behavioral assays of memory. The specific aim of this project was to investigate the neurochemical effects of direct intracerebral infusion of amyloid-β oligomers in the rat. Experiment 1 investigated direct infusions of synthetic …

Effect Of Neurotrophic Factors On Cholinergic Neurons In The Septo-Hippocampal Pathway Of Normal And Af64a Treated Rats, Christopher Andrew Willson

Dissertations

No abstract provided.

The Role Of Methylation And Chromatin Structure In The Regulation Of The O6-Methylguanine-Dna Methyltransferase (Mgmt) Gene In Human Glioma Cells, Joseph F. Costello

Dissertations

No abstract provided.

An Anatomical And Physiological Investigation Of Hippocampal Connections Involved In Cardiovascular Control, Kenneth Gary Ruit

Dissertations

No abstract provided.