Medicine and Health Sciences Commons^™

Investigations Into The Relationship Between Menopause And Alzheimer’S Disease Pathology In A Mouse Model With Ovarian Follicle Depletion, Amanda M. Leisgang Osse

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s Disease (AD) currently affects about 6.9 million Americans, with over two-thirds of those individuals being women. Interestingly, changes in the brain indicative of AD coincide with the onset of menopause. Post-menopausal women have significantly higher levels of AD pathologies, including amyloid beta and hyperphosphorylated tau, than pre-menopausal women. To investigate the relationship between AD pathologies and menopause, we induced menopause-like state in an AD mouse model, APP/PS1, by treatment with 4-vinylcyclohexene diepoxide (VCD) to accelerate ovarian follicle depletion. To monitor the transition to menopause, vaginal lavages and cytology was performed to determine if mice reached anestrous. Both female APP/PS1 …

A Low Dose Of Electro-Psychedelic Treatment Increases Neuronal Dendritic Arborization And Filopodic Spine Density, Elaine Aquino Vasquez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Neuropsychiatric disorders remain a formidable challenge to the global healthcare system, necessitating innovative treatments to address their complex pathophysiology. Alternative therapeutic approaches, including electroconvulsive treatment (ECT) and psychedelics, have gained attention for their capacity to relieve a broad range of symptoms. ECT is a long-standing effective therapy for patients, especially treatment-resistant ones. Psychedelics, like psilocybin, can induce profound and sustained therapeutic effects. The limited understanding of their mechanisms of action, compounded by the negative stigma surrounding ECT and psilocybin, prevents them from being used as adjunct agents. ECT and psilocybin promote synaptic plasticity and modulate neural remodeling, yet their comparative …

The Mitochondrial Membrane Potential As A Screening Tool For Immunostimulation, Kendra Mcglothen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The rise of neuroinflammatory disorders highlights the importance of early detection and intervention for more effective treatment options. Neuroinflammation is associated with the pathogenesis of many neurological disorders, including Major Depressive Disorder, Alzheimer's disease, and Multiple Sclerosis. There has been a focus on neurons to advance our understanding of the underlying mechanisms of neuroinflammation and its role in neurodegeneration. However, recent studies have highlighted the pivotal role of glial cells, particularly microglia, in neuroinflammation due to their active participation in the immune response. This study investigates glial-specific indicators of morphology, metabolic changes, and drug efficacy in neuroinflammatory conditions. By analyzing …

The Feasibility Of High-Intensity Training To Improve Self-Control And Occupational Participation In At-Risk Adolescents, Tashia Kaplan

UNLV Theses, Dissertations, Professional Papers, and Capstones

PurposeAdolescence is a challenging time navigating self-control and decision-making, creating vulnerability to developing poor habits and unhealthy behaviors. This feasibility study aimed to determine if a high-intensity training program (HIT) would improve self-control, health-related behaviors, and healthy occupational participation in at-risk adolescents in the Real Talk Youth Impact Program (Real Talk), measured by the Occupational Experience Profile (OEP).

Methodology Three at-risk adolescent were recruited via convenience sampling from Real Talk to participate in a twelve-session HIT intervention, one participant completed all sessions. Researchers used a quasi-experimental exploratory sequential mixed-methods design to examine self-control, health-related behaviors, and occupational participation measured …

The Influence Of Bilateral Dual Source Transcranial Direct Current Stimulation On The Progression Of Muscle Fatigue, Eliza Clinton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Transcranial direct current stimulation (tDCS) applied unilaterally to the primary motor cortex (M1) can significantly prolong the time to task failure (TTF) of a fatiguing contraction. The primary purpose of the study was to examine the influence of bilateral dual source tDCS (dstDCS) applied over the left and right M1s (ds-tDCS) on the TTF of a precision grip task. This was accomplished through the utilization of a double-blind, randomized, SHAM-controlled, within-subjects design. Fourteen participants completed two experiments (ds-tDCS and SHAM stimulation conditions) with a seven-day washout period between sessions. Each experiment involved the performance of a sustained isometric fatiguing contraction …

The Influence Of Bihemispheric Transcranial Direct Current Stimulation On Muscle Fatigue, Ananya Singh Chauhan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Unilateral transcranial direct current stimulation (tDCS) using two electrodes placed over the primary motor cortex (M1) and the contralateral supraorbital (SO) region (M1-SO montage) has been shown to decrease the progression of muscle fatigue. The primary purpose was to determine the impact of bihemispheric tDCS (bi-tDCS) applied over the left and right M1s (bi-tDCS) on the time to task failure (TTF) of a precision-grip task. The study implemented a double-blind, randomized, SHAM-controlled, within-subjects design. A total of 20 participants performed two experimental sessions (bi-tDCS and SHAM conditions) separated by a one-week washout. During each experimental session, a fatiguing isometric contraction …

The Genetic Relationship Between Peripheral Inflammation And Alzheimer’S Disease, Davis Cammann

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s disease (AD) is the leading cause of dementia worldwide, and has become an ever-present problem in aging populations. An increasing body of evidence suggests that neuroinflammation is one of the key drivers of AD pathology. One overlooked contributor to this burden is peripheral inflammation throughout the body. Due to increased permeability of the blood-brain-barrier (BBB) in older age, inflammatory plasma proteins and immune cells infiltrate the CNS and drive neuroinflammation through interactions with neurons and glia. In addition, age-related changes in the composition of gut microbiome taxa lead to increased gut permeability and inflammatory burden. Because inflammatory factors are …

Systems Dynamics Of The Anterior Cingulate Cortex And Hippocampus In Behavioral Switching, Spatial Working Memory, And Disease, Ryan Wirt

UNLV Theses, Dissertations, Professional Papers, and Capstones

The electrophysiological properties of the hippocampus (HC) and anterior cingulate cortex (ACC) are the central focus of research on learning, memory, and neurological disease. Previous research has shown that HC is essential for forming new memories, spatial navigation, and temporal processing. While the function of ACC, located within the medial prefrontal cortex, remains controversial, it has a role in long-term memory recall, processing pain, monitoring current state, learning, schema updates, and information integrations. Interactions between the ACC and HC occur during social memory, spatial working memory performance, and long-term memory recall. Notably, the HC and ACC are among the first …

Markers Of Neuroinflammatory And Degenerative Processes In Professional Athletes With Traumatic Encephalopathy Syndrome, Brooke Conway Kleven

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: The clinical criteria for Traumatic encephalopathy syndrome (ccTES) were developed to improve the diagnosis of Chronic traumatic encephalopathy (CTE). This study aimed to determine whether there was an association between a clinical diagnosis of Traumatic encephalopathy syndrome (TES) and changes in serum biomarkers, balance, neuroimaging, and cognition among athletes in the Professional Athletes Brain Health Study (PABHS).Methods: Of the cohort, 130 professional fighters met age or retirement criteria and went to a consensus conference, with 52 fighters (40%) meeting the criteria for TES. A generalized linear model with generalized estimating equations was utilized to assess the odds of disease …

Dimensionality Of Natural Auditory Scene Perception: A Factor Analysis Study, Margaret A. Mcmullin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Theories of auditory and visual scene analysis suggest the perception of scenes relies on the identification and segregation of objects within it, resembling a detail-oriented processing style, but it is possible that a global-oriented process also occurs while evaluating auditory scenes. There is evidence for global properties that enable rapid recognition of visual scenes, even without recognizing the individual objects comprising the scene. It is our understanding that a similar line of research has not been explored in the auditory domain; therefore, we evaluated the contributions of high-level global and low-level acoustic information to auditory scene perception. A secondary aim …

Cognitive Testing For Sport Concussion: The Immediate Post-Concussion Assessment And Cognitive Testing (Impact), Julia E. Maietta

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sport concussion is among the most common injuries for an athlete to experience during sport participation. Because of the complex pathophysiological process that affects the brain during and after concussion, symptoms can be heterogeneous in presence and severity. Although most acute symptoms (e.g., headache, slowed processing speed, loss of consciousness, irritability, depression, anxiety) resolve within seven to 10 days for most athletes, there is evidence that higher initial symptom burden and other genetically based differences can lead to longer symptom duration and complicated recovery post-concussion. Because structural changes that commonly occur as a result of concussion (e.g., diffuse axonal injury) …

The Effects Of Executive Function Between Anxiety And Math Achievement In Adolescents, Mckenzie Hall

UNLV Theses, Dissertations, Professional Papers, and Capstones

Anxiety in Children can develop into pervasive disorders in adulthood if not treated. Research shows dysfunctional Executive Function (EF) and anxiety are both shown to have a negative impact on math achievement in children and adolescents (Trezise & Reeve, 2018; Kalaycioglu, 2015; Owens, Stevenson, Hadwin & Norgate, 2012). Chung, Weyandt, and Swentosky (2014) found biological and neuropsychological support for EF as a unitary and multifaceted processor for regulating our emotional states as well as our daily procedures. Anderson’s (2002) model of Executive Control System (ECS) allows the factors of EF to be examined using a developmental approach towards EF processes. …

Axon Initial Segment Morphology Across Typical Cortical Development And In Mouse Models Of Neurodevelopmental Disorders With A High Incidence Of Epilepsy, Rachel Ali Rodriguez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Neurodevelopmental disorders (NDDs) are commonly associated with a high incidence of epileptic seizures which result from excessive firing of neurons. The axon initial segment (AIS) is a neuronal compartment essential for the control of activity patterns of neurons. The AIS undergoes important modifications during development, but the molecular mechanisms that affect the development, morphology, and protein composition of the AIS are still not well understood. We examined AIS morphology of medial prefrontal cortex (mPFC) pyramidal neurons in wildtype mice across development and in two mouse models of NDDs. Results indicate restructurings at the AIS during typical development, some of which …

Designs And Outcomes Of Transcranial Magnetic Stimulation (Tms) And Repetitive Transcranial Magnetic Stimulation (Rtms) Circuits, Daniel Senda

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis reports the design and outcomes of several circuits intended for transcranial magnetic stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS) research. In simple terms, TMS circuits are composed of four main blocks: high voltage power source, energy storage bank, control switch, and coil. Each one of these blocks has characteristics that influence how well the circuit will perform for TMS procedures. A successful TMS research circuit must have the ability to emit controlled electromagnetic pulses through a coil connected to it. For the first block, voltages ranging from 50 V to 2 kV were used. In the second …

Multiple Approaches To Auditory Rhythm: Development Of Sustained Musical Beat And The Relation To Language, Development Of Rhythmic Categories Via Iterated Production, And A Meta-Analytic Study Of Neural Entrainment To Beat, Karli Marie Nave

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rhythm is ubiquitous to human communication, coordination, and experience of music. In this dissertation, I address three empirical questions through three different methodologies, all of which contribute to the growing body of literature on human auditory rhythm processing. In Chapter 2, I present a registered report detailing the results of independent conceptual replications of Nozaradan, Peretz, Missal, & Mouraux (2011), all using the same vetted protocol. Listeners performed the same tasks as in Nozaradan et al. (2011), with the addition of behavioral measures of perception. In neuroscience, neural correlates to musical beat perception have been identified, yet little to no …

Development Of A Novel Cognitive-Motor Dual Task Assessment Battery In Neurodegenerative Disease, Jason Longhurst

UNLV Theses, Dissertations, Professional Papers, and Capstones

Automaticity --- the ability to perform a task with directing attentional resources to its completion --- is commonly reduced among individuals with neurodegenerative diseases. These automaticity deficits result in impaired functional and daily activities and are sensitive to subtle, subclinical impairments. However, current measurement of automaticity by dual task paradigms is methodologically limited. In order to gain insight into the current state of the literature regarding cognitive-motor interference in symptomatic and prodromal neurodegenerative disease, the author of this dissertation conducted a scoping review (Chapter 1). To address the methodological limitations of current measurement of automaticity, a new measurement tool was …

Association Between White Matter Hyperintensities, Cortical Thinning, And Clinical Outcomes In Mild Traumatic Brain Injury, Thomas Helmut Knoblauch

UNLV Theses, Dissertations, Professional Papers, and Capstones

Traumatic Brain Injury (TBI) is a global health challenge, with over 4.6 million confirmed cases annually in North America alone. Mild traumatic brain injuries (mTBIs) are the most common and make up approximately 81% of all TBI diagnoses worldwide [1]. Studies indicate that 10–15% of patients suffer from trauma induced symptoms (i.e. headache, loss of balance, cognitive impairments, fatigue, and mental health/affective disorders) as far as 1 year post injury [2]. Prediction and management of these post-traumatic sequalae is complicated by a lack of symptom associated neuroimaging findings. In spite of a “prominent distribution” of frontotemporal WMHs in pediatric subjects …

The Influence Of Cerebellar Transcranial Direct Current Stimulation On Motor Function In Parkinson’S Disease, Lidio Lima De Albuquerque

UNLV Theses, Dissertations, Professional Papers, and Capstones

Parkinson's disease (PD) is the most common movement disorder and the second most common neurodegenerative disorder. PD is characterized by dopaminergic cell loss in the substantia nigra pars compacta, which leads to a reduction in dopamine in the striatum. These physiological mechanisms lead to a number of motor impairments such as bradykinesia, rigidity, tremor, and postural instability that severely limit the ability of individuals with PD to perform many essential daily living activities. Although current pharmacological, surgical, and physical exercise treatment approaches are valuable they are either only mildly effective, expensive, or associated with a variety of side effects. Therefore, …

Restructuring Of The Axon Initial Segment In Mouse Models Of Neurodevelopmental Disorders, Rachel Ali Rodriguez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Neurodevelopmental disorders (NDDs) affect more than 36% of children in countries with low- and middle- incomes (Boivin, 2015; McCoy, 2016). Interestingly, these heterogeneous disorders share a high incidence of epileptic seizures, suggesting a shared pathology. Seizures result when neuronal firing activity becomes disturbed and neurons fire excessively or in unregulated patterns. A key site in the control of neuronal firing patterns is the axon initial segment (AIS), where the local density of proteins and the morphology of the AIS in part determine the firing of neurons. We hypothesized that a disruption in the morphology and/or composition of the AIS can …

Reduced Gabaergic Signaling At The Axon Initial Segment Decreases Vigilance State Transitioning, Austin John Boren

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sleep is a highly regulated homeostatic process that is disrupted in an estimated 50-70 million Americans. Regulation of sleep depends upon coordinated signaling of multiple neurotransmitter systems. In particular, inhibitory gamma-aminobutyric acid (GABA) signaling is required to suppress wake-active brain regions in order to initiate and maintain sleep states. GABA type A receptors (GABAARs) are ionotropic receptors with subunit compositions uniquely enriched on subcellular domains of target cells. α2 subunit-containing GABAARs are the primary target of GABA released onto the axon initial segment (AIS), a site critical for phasing the oscillatory activity of cortical cells. α2-containing GABAARs have previously been …

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 …

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 …

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 …

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. …

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 …

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 …