Neurosciences Commons^™

Changes In Hippocampal-Anterior Cingulate Cortex Interactions During Remote Memory Recall, Ryan A. Wirt

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spatial memory is an important cognitive process that relies on extensive neural networks throughout the brain. The hippocampus (HC) is important for the formation of these memories but over time, in a process referred to as consolidation, recall becomes increasingly reliant on other brain areas. The anterior cingulate cortex (ACC), a region within the medial prefrontal cortex, is important for spatial learning, spatial working memory, and remote memory recall, but the mechanisms underlying recall processes are still unknown. To better understand the role of the ACC and HC during memory recall, we introduced rodents into a series of spatially and …

An Evaluation Of Alzheimer's Disease-Related Pathology In Two Different Models Of Diabetes In Immune-Challenged Mice, Andrew Scott Murtishaw

UNLV Theses, Dissertations, Professional Papers, and Capstones

Obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome are related disorders with wide-ranging and devastating effects that can be observed throughout the body. One important and understudied organ of damage is the brain. Clinical and epidemiological studies have found that T2DM, and more specifically hyperinsulinemia, significantly increases the risk of cognitive decline and increases the likelihood of Alzheimer’s disease (AD) and other forms of dementia in the elderly. Insulin has slightly different functions in the peripheral body than in the central nervous system and the dysregulation of these functions may contribute to the onset and progression of late-life neurodegenerative …

Exercise, Learning And Emotional Health: Interdisciplinary Approaches To Translational Action, Tessa L. Koschel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Exercise positively effects physical, psychological and neurological wellbeing. Though the population at large is becoming increasingly aware of the multi-faceted benefits of exercise, the majority of people fail to meet daily exercise recommendations. Largely, demands of everyday life such as work, school and family take priority over fitness. The issue therefore becomes a matter of time. In a world of media multi-tasking and immediate gratification, the challenge to health professionals becomes incorporation and manipulation of these consistencies to improve exercise uptake and adherence. Focus must shift from the idea of making additional time for exercise, to adding exercise to time …

The Psychophysiological Correlates Of Personality, Trauma, Posttraumatic Stress Disorder And Social Support, Meghan E. Pierce

UNLV Theses, Dissertations, Professional Papers, and Capstones

Theories considering the etiology of psychopathy suggest that trauma exposure, specifically childhood maltreatment and sexual abuse, is related to the development of callous-unemotional traits in children and adolescents, which are precursors to psychopathic traits in adulthood. Furthermore, posttraumatic stress disorder has an opposite relationship with many of the emotional and behavioral components of the two-factor model of psychopathy. Specifically, PTSD is positively associated to IA and traits associated with it and negatively associated with FD. Thus, this study sought to expand upon the current theories of a trauma-based etiology of psychopathy by investigating the relationship between trauma, PTSD, and psychopathic …

Neural Processes Underlying Auditory Context Effects, Breanne Yerkes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Auditory information within our natural environments is disorganized and often ambiguous, leaving our auditory systems with a complex task: organizing sound into coherent objects. The auditory system uses both current and prior information to assist in completing this task. The influences of previous context on current perception have been referred to as context effects. A contrastive context effect results in a current perception that is opposite of what is expected based on the physical stimulus properties presented during an immediate context. A facilitative context effect results in a current perception that is the same as the perception during the immediate …

An Evaluation Of Gabab Receptors On Modulating Neuroinflammation In A Non-Transgenic Animal Model Of Alzheimer's Disease, Monica Bolton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and distinct neuropathological hallmarks, including amyloid beta plaques and neurofibrillary tau tangles (NFT). Although the etiology remains to be discovered, several risk factors exist that significantly contribute to developing AD. Diabetes is one of the major risk factors associated with AD and is characterized by disrupted insulin signaling that may contribute to or exacerbate AD pathologies. Furthermore, both disorders result in increased neuroinflammation. Considerable evidence has demonstrated that a chronic inflammatory response, in particular chronic microglia activation, promotes A production as well as the hyperphosphorylation of tau through …

Assessing Clinical Significance Of The Immediate Post-Concussion Assessment And Cognitive Testing Battery When Comparing Adjusted And Unadjusted Rci Methods For Different Ranges Of Baseline Scores, Ashley N. Figaro

UNLV Theses, Dissertations, Professional Papers, and Capstones

The growing concern revolving around the dangers of sports-related concussions have led to the most recent implementation of neurocognitive (NC) test batteries as a means to objectively determine the presence of a cognitive defect. Whereas any other sports-related injury can be diagnosed with tools such as an x-ray or MRI, a concussion represents a metabolic disturbance that cannot be identified by these diagnostic tools. Many neurocognitive test batteries employ statistical techniques to derive cut off scores in order to represent significant or insignificant changes as compared to individual baseline scores, or pre-established normative values. If an individuals’ post-injury score exceeds …

The Effect Of Sleep On Perceptual Learning And Memory Consolidation, Vanessa Claire Irsik

UNLV Theses, Dissertations, Professional Papers, and Capstones

An ability to segregate speech accurately is essential given that most auditory environments contain other overlapping conversations or environmental noise. While perceiving speech among background noise can be difficult in and of itself, those with hearing impairments can experience considerable difficulty. While training has been shown to benefit perceptual segregation of trained sounds, it is unclear how such training transfers to sounds not included in a training regimen. The current study aimed to address this question by training listeners on a portion of sounds during a vowel segregation task, and subsequently testing on both the trained sounds and untrained sounds. …

Functional Capacity In Schizophrenia: Relationship Among Effort, Reinforcement Learning And Self-Beliefs, Sally J. Vogel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Individuals with schizophrenia exhibit a wide range of complex neurocognitive, psychiatric and behavioral impairments. Recent research suggests that this complex array of symptoms can be at least partially accounted for by dysfunction in more basic mechanisms, such as the ability to learn from positive and negative reinforcement, or the ability to exert adequate effort when completing simple tasks. Evidence also suggests that deficits in these basic mechanisms may contribute to more complex symptoms, such as functional impairment. Also, the relationship between neurocognitive deficits and functional impairment has been found to be mediated by defeatist performance beliefs. However, studies have not …

A Comparison Of The Effects Of Different Doses Of Gabab Receptor Ligands On Spatial Learning And Memory And Memory Flexibility, Chelcie Heaney

UNLV Theses, Dissertations, Professional Papers, and Capstones

The principal inhibitory neurotransmitter in the brain, gamma amino-butyric acid (GABA), mediates several types of learning and memory. Of the two main receptor subtypes for GABA, the in vivo role of GABAB receptor in learning and memory is less well characterized and the current data often conflict. Based on the current literature, it is unclear, for instance, whether enhancing GABAergic activity via the GABAB receptor could be beneficial for or detrimental to learning and memory. Hippocampally-dependent learning and memory tasks are of particular interest due to their clinical relevance to patients with schizophrenia or Alzheimer’s disease, who exhibit impaired performance …

Postural Sway And Brain Hemispheric Power Spectral Density Under Different Attentional Focus Conditions, Sharon Jalene

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to determine the differences, if any, in the root mean square error (RMSE) of postural sway and hemispheric power spectral density (PSD) in the alpha and beta bands (8-12Hz and 12-25Hz) during different conditions of attentional focus (i.e., internal focus (IF), and external focus (EF) and a control condition (C)). Previous studies have shown that the adoption of IF and EF significantly alter motor performance and that EF promotes automaticity (Wulf, 2013). Sports performance and balance studies utilizing EEG spectral analyses report increased alpha oscillations during expert performance and stable balance and increased beta …

Hemispheric Asymmetry In The Perception Of Musical Pitch Structure, Matthew Adam Rosenthal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Both the left and right hemispheres contribute to the perception of pitch structure

in music. Music researchers have attempted to explain the observed asymmetries in the perception of musical pitch structure by characterizing the dominant processing style of each hemisphere. However, no existing characterizations have been able to account for all of the empirical findings. To better explain existing empirical findings, this dissertation characterizes the left hemisphere as dominant in temporal pitch processing (i.e. with respect to the sequential ordering of pitches) and the right hemisphere as dominant in non-temporal pitch processing (i.e. without respect to the sequential ordering of …

The Effect Of Acute Lps-Induced Immune Activation And Brain Insulin Signaling Disruption In A Diabetic Model Of Alzheimer's Disease, Andrew Scott Murtishaw

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer's disease (AD) is a neurodegenerative disorder marked by progressive cognitive impairments and pathological hallmarks that include amyloid plaques, neurofibrillary tangles, and neuronal loss. Several well-known mutations exist that lead to early-onset familial AD (fAD). However, these cases only account for a small percentage of total AD cases. The vast majority of AD cases are sporadic in origin (sAD) and are less clearly influenced by a single mutation but rather some combination of genetic and environmental risk.

The etiology of sAD remains unclear but numerous risk factors have been identified that increase the chance of developing AD. Among these risk …

Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Schizophrenia is a debilitating mental disorder that affects up to 3% of the world population. The behavioral symptoms are categorized into positive and negative symptoms, which appear during late adolescence/early adulthood. Unfortunately, the underlying cellular and molecular mechanisms of the disease are poorly understood. Several hypotheses exist to explain mechanisms contributing to these behavioral alterations. One model proposes that a reduced function of the NMDA glutamate receptor on specific GABAergic interneurons may be responsible for deficits in schizophrenia. Post-mortem investigations provide evidence of reductions in both glutamate and GABA-related proteins in patients with schizophrenia. Further, GABAergic interneurons that are activated …

Using Over-The-Counter Ear Filters As A Treatment To Improve Dizziness And Balance In Patients Diagnosed With A Traumatic Brain, Brandy Sue Whitney

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background and purpose: People diagnosed with a Traumatic Brain Injury (TBI) usually have physical, cognitive, emotional, and sleep deficits. Sensory overload is a common symptom of TBI. One treatment prescribed for sensory overload is over the counter ear filters. Ear filters have shown to decrease sensory input. Could the ear filters have an effect on balance and dizziness without much cost to the patient or the clinic?

Subjects: Patients diagnosed with a mild or moderate brain injury, ages of 18-65 years old. They needed to be medically stable, potential to walk, and have complaints of dizziness and/or balance problems.

Methods: …

The Effects Of Chronic Calcium Dysregulation On Behavioral And Pathological Features Of Alzheimer's Disease, Jonathan Sabbagh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer's disease (AD) is a progressive neurodegenerative disorder whose etiology is unknown. Recent studies have implicated alterations in calcium homeostasis as a pathogenic contributor to AD. Calcium dysregulation has been observed in aged and AD brains, an event which could potentially facilitate the development of multiple pathologies observed in AD. Specifically, disrupting intracellular calcium levels in vitro has been demonstrated to increase amyloid-beta (Aβ) production, tau phosphorylation, and neuronal loss. However, there is a paucity of data on the behavioral and biochemical consequences of chronic in vivo perturbation of calcium homeostasis. In a series of experiments designed to evaluate the …

Frequency-Specificity And Pattern-Specificity Of The Buildup Of Auditory Stream Segregation, David Michael Weintraub

UNLV Theses, Dissertations, Professional Papers, and Capstones

During repeating sequences of low (A) and high (B) tones in an "...ABAB..." pattern, the likelihood of hearing two separate streams ("streaming") increases with more repetitions of the patterns, a phenomenon referred to as "buildup". Previous studies have shown that buildup is frequency specific (Anstis & Saida, 1985) and that its biasing effects decays over several seconds (Beauvois & Meddis, 1997). No study has examined whether the frequency specificity of buildup persists for such a long duration. To address these issues, Experiment 1 tested the decay of frequency-specific and non-frequency specific buildup. The results revealed that (1) frequency-specific buildup effects …

An Investigation Of The Role Of Gabab Ligands On Cued And Contextual Fear Conditioning, Chelcie F. Heaney

UNLV Theses, Dissertations, Professional Papers, and Capstones

GABA is the primary inhibitory neurotransmitter in the brain and mediates several processes, including learning and memory. Activating or inhibiting GABA receptors allows for the examination of the effects of altered GABAergic signaling on these processes. The two main receptors, GABAA and GABAB, each have a different mechanism of action when activated, thus they may contribute differentially to learning and memory. The metabotropic GABAB receptor responds with the activation of several intracellular signaling cascades, which provide long-lasting inhibitory effects that primarily mediate network function. Conversely, the GABAA receptor is an ion channel that contributes more immediate inhibitory effects through the …

Exercise-Induced Neuroprotection In A Hemiparkinsonian 6-Hydroxydopamine Rat Model, Merrill Russen Landers

UNLV Theses, Dissertations, Professional Papers, and Capstones

Outside of finding a cure, one of the preeminent goals of research in Parkinson's disease (PD) is finding a neuroprotective treatment that when applied prior to the onset of the disease will decrease the risk and severity of the subsequent disease. One such treatment that has potential as a neuroprotective agent in PD is exercise. Several studies have found forced exercise to be protective of Parkinson's disease in adult rodent models; however, few of these studies have used a design wherein voluntary exercise was evaluated. Moreover, no study has used a true neuroprotective design in which exercise was applied prior …

Effects Of Hyperthermia On Photochemical Internalization-Mediated Delivery Of Bleomycin, Christina Schlazer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Standard treatment protocols for high-grade gliomas, such as glioblastoma multiforme (GBM), are highly ineffective due to their inability to eradicate infiltrating tumor cells. Improvements in overall survival are likely to be realized only with the development of more effective localized therapies capable of eradicating tumor cells in the surgical resection margin and beyond. Photochemical internalization (PCI) is a localized light-based therapeutic modality that enhances the efficacy of therapeutic macromolecules including chemotherapeutic agents such as bleomycin. A number of studies have shown that this photodynamic therapy (PDT) - based modality may prove effective in the treatment of high-grade gliomas.

Three-dimensional multicell …

A Diffusion Tensor Imaging Software Comparison And Between Control Subjects And Subjects With Known Anatomical Diagnosis, Michael C. Moore

UNLV Theses, Dissertations, Professional Papers, and Capstones

Diffusion weighted imaging (DWI) is a magnetic resonance imaging (MRI) method that produces in vivo images of biological tissues weighted with the local micro-structural characteristics of water diffusion. Diffusion tensor imaging (DTI), a form of DWI, is useful when a tissue, such as the neural axons of white matter in the brain, has an internal fibrous structure that allows water to diffuse more rapidly in alignment with the fibers. Changes in the water diffusion pattern indicate changes in the fiber structure which can result from damage to the fibers. Measurements of the water diffusion patterns include overall diffusivity, Apparent Diffusion …

Executive Function Profiles In Pediatric Traumatic Brain Injury, Erik Nelson Ringdahl

UNLV Theses, Dissertations, Professional Papers, and Capstones

Traumatic brain injury is a common cause of disability and death among children in the United States. Insult to the frontal and temporal lobes are frequent in closed head brain injury. Cognitive deficits in a variety of domains are common sequelae of brain trauma. In many cases, trauma to the frontal and temporal lobe regions engender prominent deficits in higher-order cognitive processing, memory, and attention.

Higher-order cognitive processing, or Executive Functions are the grouping of cognitive processes necessary for organization of thoughts and activities, attending to the activities, prioritizing tasks, managing time efficiently, and making decisions (Alvarez & Emory, 2006; …

Donepezil And Galanin Interactions In An Animal Model Of Alzheimer’S Disease, Jonathan J. Sabbagh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer's disease (AD) is a neurodegenerative disorder marked by a progressive loss of cognitive function. One of the neurobiological hallmarks of AD is a progressive loss of cholinergic neurons and a decrease in the amount of acetylcholine in the brain. Pharmacological therapies have targeted the cholinergic system, specifically first-line, palliative treatment using acetylcholinesterase (AChE) inhibitors, such as donepezil. Donepezil has been shown to increase cholinergic tone and ameliorate some of the cognitive deficits in AD patients. Galanin, a neuropeptide that inhibits the evoked release of several neurotransmitters including acetylcholine as well as modulates seveal intracellular cascades, is overexpressed in AD …

Protocol Variation Analysis Of Whole Brain Ct Perfusion In Acute Ischemic Stroke, Peter T. Heiberger

UNLV Theses, Dissertations, Professional Papers, and Capstones

Computed tomography perfusion (CTP) analysis is a rapidly advancing imaging modality that is improving diagnosis of brain abnormalities in patients suffering from hemorrhagic or ischemic stroke, traumatic brain injury, vascular occlusion and numerous other conditions. Through the advancements of computed tomography (CT) imaging, including the introduction of the 320-detector row CT with a 16 centimeter range in the z-axis enabling whole brain CTP, perfusion analysis now has a significantly increased clinical utility that is useful for both diagnosis and treatment of central nervous system (CNS) conditions. This study focuses on the procedural and analytical approach to the diagnostic evaluation of …

Development Of A Functional Mri Olfactory Protocol, Jeremy Mangum

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many people can spend a few days with an acute form of sinusitis, a stuffy nose, or sinus congestion that inhibits their ability to smell, but there are fourteen million Americans over the age of fifty that suffer from some form of chronic olfactory dysfunction. Some neurological disorders such as Parkinson's disease and Alzheimer's disease have demonstrated that olfactory dysfunction is a frequent and early sign. While these diseases have no known cure, there are medicines that exist to slow the progression of such debilitating illnesses. By identifying such diseases in their early stages, we can improve the quality of …