Other Neuroscience and Neurobiology Commons^™

Hierarchy In Sensation: Exploring The 40 Hz Auditory Steady State Synchrony In The Primary Auditory And Prefrontal Association Cortices, Deepshila Gautam

Electronic Theses and Dissertations

Auditory processing begins in the cochlea and ascends through brainstem relays to the cortex, where sound features with increasing complexity are encoded. The 40 Hz auditory steady-state response (ASSR) reflects induced gamma synchrony shaped by local cortical circuit dynamics. Disrupted 40 Hz ASSR is a consistent finding in schizophrenia, linked to N-methyl-D-aspartate receptor (NMDAR) hypofunction in inhibitory interneurons, making it a promising translational biomarker. While multiple ASSR generators have been identified, it is not known if these are redundant or represent unique activity. This dissertation investigates regional differences in 40 Hz ASSR across two principal generators: the primary auditory cortex …

Defining The Peripheral Plasticity Of Nociceptive Afferents Following Spinal Cord Injury And Physical Therapy Intervention., Morgan Julianna Forston

Electronic Theses and Dissertations

The focus of this dissertation is to explore the peripheral plasticity of nociceptive afferents following spinal cord injury (SCI) and whether it is exacerbated or induced when physical therapy-based muscle stretching, a therapy we have shown to be detrimental to locomotor recovery in rodents, is implemented post-SCI. Chapter I provides a brief introduction on sensory afferents with particular emphasis on nociceptive afferents and their multifaceted role within the peripheral and central nervous systems. Chapter II describes SCI epidemiology and common sensory related complications that occur in patients as well and pharmaco- and physical therapies that are employed post-SCI. Chapter III …

Establishing A Mouse Model Of Cerebral/Cortical Visual Impairment., Dana K. Oakes

Electronic Theses and Dissertations

Cerebral/cortical visual impairment (CVI) is a disorder most often caused by perinatal hypoxic injury to the developing brain. CVI is the leading cause of childhood visual impairment in developed nations, encompassing deficits in many aspects of vision including visual acuity, contrast sensitivity, and object recognition. The pathophysiology of CVI is not well understood because no animal model currently exists to study this disorder. Because there is no animal model, the pathophysiology of CVI is poorly understood. Here, we developed a murine early postnatal hypoxic model of CVI by exposing mice to 9.5% O₂ at postnatal day (P)3 for a …

Role Of The Anti-Viral Immune Response In Neural Cell Modulation And Neurological Sequelae Of Childhood Viral Infections, Yashika Kamte

Electronic Theses and Dissertations

Viral infections of the central nervous system (CNS) often result in neurological sequelae and are considered a risk factor for the development of neurological disease. Moreover, the outcomes of a viral infection are largely dependent on the age of the host, with younger hosts developing more profound neuropathology. Perhaps the developing brain coupled with an immature immune system contributes to worse outcomes in the very young. Children suffering from brain infections are more prone to develop enduring neurological impairments even after recovery from the infection. Although majority of the brain growth occurs in utero, neurodevelopment continues throughout the juvenile …

Novel Insights Into Oligodendrocyte Biology From Developmental Myelination Studies In Autophagy Deficient Mice And Analysis Of Oligodendrocyte Translatome Response To Contusive Spinal Cord Injury., Michael David Forston

Electronic Theses and Dissertations

Loss of myelin causes severe neurological disorders and functional deficits in white matter injuries (WMI) such as traumatic spinal cord injury (SCI). This dissertation is focused on autophagy in OL development and the OL translatome after SCI. Chapter I describes the history of myelin, OL development, and their involvement in neurodegenerative diseases and SCI. The proteostasis network, in particular autophagy, and its contributions to white matter pathology is discussed. It concludes examining advantages and disadvantages of unbiased omics tools, like RiboTag, to study transcriptional/translational landscapes after SCI. Chapter II focuses on autophagy in OPC/OL differentiation, survival, and proper myelination in …

Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale

Electronic Theses and Dissertations

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic …

Effect Of Dorsal Quadrant Or Ventral Quadrant Spinal Cord Injury On Gait Features During Locomotion., Anya Nicole Trell

Electronic Theses and Dissertations

In the Unites States, approximately 1.5 million people currently have a spinal cord injury and suffer permanent sensory and motor loss due to the disruption of the spinal cord. Due to the significant morbidity, it is vital to understand the functional impact of disrupting neural descending pathways that modulate spinal neurons involved in intermuscular coordination critical for gait behaviors. Tasks that are more difficult require additional input from these neural pathways; therefore, fourteen feline subjects were familiarized with level overground locomotion and stair descent gait tasks. After collection of baseline kinematic data, the subjects received either a dorsal or ventral …

Sex-Specific Effects Of Chaperone And Glial Defenses On Experimental Lewy Body Disease, Tarun Bhatia

Electronic Theses and Dissertations

Lewy body disorders are a group of neurodegenerative conditions characterized by the pathological misfolding and aggregation of the abundant protein, α-synuclein. The most common Lewy body disorders are Parkinson’s disease and dementia with Lewy bodies. Apart from ageing, male sex is a major risk factor for Lewy body disorders, as men are at ~1.5-fold higher risk for these diseases than women. Yet, preclinical studies on Lewy body disorders rarely examine sex as a biological variable, and the mechanisms underlying sex-skewedness in disease risk remain undetermined.

Here, we developed a sex-stratified model of Lewy body disorders by exposing primary neurons harvested …

Investigations Of Potential Mechanisms Underlying Spinal Cord Injury-Induced Polyuria., Jason H. Gumbel

Electronic Theses and Dissertations

Spinal cord injury (SCI) results in neurological impairments including motor, sensory, and autonomic dysfunction. These neurological deficits result in a litany of complications apart from muscular paralysis, including bladder, bowel, cardiovascular, and sexual function. SCI-induced polyuria (the overproduction/passage of urine) remains understudied, and therefore mechanisms behind it are largely unknown and require extensive investigation for potential targeted therapies to improve quality of life. The objective of this dissertation was to investigate potential mechanisms of SCI-induced polyuria and explore potential therapies to improve quality of life in the SCI population. Metabolic cages, Western blot, enzyme-linked immunoassay, and immunostaining were first used …

Vitamin B12 Deficiency Does Not Stimulate Amyloid-Beta Toxicity In A Ceanorhabditis Elegans Model Of Alzheimer’S Disease, Opeyemi F. Showemimo

Electronic Theses and Dissertations

Alzheimer’s disease (AD) is symptomized by amyloid-beta plaques in the brain and accounts for more than 65 percent of dementia cases. Vitamin B12 (cobalamin) deficiency can result in similar cognitive impairment and roughly 15% of the elderly are vitamin B12 deficient. Vitamin B12 deficiency results in the accumulation of toxic methylmalonic acid and homocysteine. Hyperhomocysteinemia is a strong risk factor for AD. To test if vitamin B12 deficiency stimulates amyloid-beta toxicity, Caenorhabditis elegans expressing amyloid-beta in muscle were fed either vitamin B12-deficient OP50-1 or vitamin B12-rich HT115(DE3) E. coli bacteria. Increased amyloid-beta toxicity was found in worms fed the …

The Role Of Vps54 In Drosophila Melanogaster Neuronal Development And Age Progressive Neurodegeneration, Emily Wilkinson

Electronic Theses and Dissertations

Vps54 is a subunit of the Golgi-associated retrograde protein (GARP) complex, which is involved in tethering endosome-derived vesicles to the trans-Golgi network (TGN). The “wobbler” mouse is the phenotypic result of a destabilizing point mutation in Vps54. This mutation causes neurodegeneration and is subsequently used as a model for human motor neuron disease. Presently, it is unclear how disruption of GARP complex function leads to motor neuron degeneration. To better understand the role of Vps54 in motor neuron development, function, and age-related neurodegeneration, we disrupted expression of the Vps54 ortholog in Drosophila and examined the impact on larval neuromuscular junction …

Differential Expression Of Rna In The Rat Peripheral Nervous System Following Nerve Injury And Treatment With Pain-Relieving Celecoxib-Loaded Nanomedicine, Andrea Stevens

Electronic Theses and Dissertations

The neuroinflammatory response to peripheral nerve injury is associated with chronic pain and significant changes in the expression profiles of RNAs in neurons, glia and infiltrating immune cells: a neuro-immune triad. Chronic constriction injury (CCI) of the rat sciatic nerve provides an opportunity to mimic neuropathic injury and quantitatively assess behavior and differential gene expression in individual animals. Macrophages that phagocytose intravenously injected nanoemulsion carrying the non-steroidal anti-inflammatory, NSAID, Celecoxib, naturally accumulate at the site of injury resulting in relief of CCI behavioral hyper-sensitivity. It is not known beyond the inhibition of cyclooxygenase-2 (COX-2) activity and the reduction in prostaglandin …

An Eeg Study On Loneliness And Recognition Memory, Carmen Jia Wen Chek

Electronic Theses and Dissertations

Loneliness, the perception of unmet social needs, has been shown to relate to recollection-based recognition deficits, but the relationship between loneliness and recognition memory (i.e., recollection and familiarity) has not been thoroughly examined. The current study hypothesized that more lonely individuals would have lower recognition memory performance, specifically recollection, with smaller ERP parietal old-new effects than less lonely individuals. Forty participants, grouped into less (n = 13) and more (n = 9) lonely groups based on their R-UCLA responses, completed an associative memory task. EEG was used to assess recognition memory effects. Results showed no significant difference in …

Ontogenetic And Adult Shape Variation In The Endocast Of Tapirus: Implications For T. Polkensis From The Gray Fossil Site, Thomas M. Gaetano

Electronic Theses and Dissertations

Endocranial morphology provides evidence of sensory ecology and sociality of extinct vertebrates. The Earliest Pliocene Gray Fossil Site (GFS) of NE Tennessee features a conspicuous dominance of skeletal elements belonging to the dwarf tapir, Tapirus polkensis. Numerous individuals in one fossil locality often suggests gregarious behavior, but sociality in T. polkensis contradicts behavior documented for extant Tapirus species. I test T. polkensis for variation in sensory and social ecology using computed tomography and 3D digital endocasts from an ontogenetic sequence. I compare the T. polkensis endocasts with extant Tapirus species using Encephalization Quotients (EQs) and 3D geometric morphometrics. Results …

Characterization Of The Effect Of Exercise Dose And Integrative Nonpharmacological Therapies In The Treatment Of Chronic Pain, Anna M. Polaski

Electronic Theses and Dissertations

Chronic pain includes debilitating conditions affecting large populations of people throughout the world. These diseases are further complicated by comorbid psychological disorders which make chronic pain conditions difficult to treat. Nonpharmacological treatment options have more recently become an important mainstay of effective therapies and are currently being used to supplement or replace traditional pharmacological treatment methods. Exercise-based therapies in particular are of interest due to their demonstrated success in reducing pain symptoms as well as improving psychological outcomes. Dose is an important factor in being able to effectively prescribe treatments in the context of specific exercise interventions and specific pain …

Glycine Receptor Expression Across Identified Retinal Ganglion Cell Types., Ian Scot Pyle

Electronic Theses and Dissertations

Retinal ganglion cells (RGCs) represent the culmination of all retinal signaling and their output forms the substrate for vision throughout the rest of the brain. About 40 different RGC types have been defined by differences in their visually evoked responses, morphology, and genetic makeup. These responses arise from interactions between inhibition and excitation throughout the retinal circuit (Franke et al., 2017; Masland, 2012; Sanes & Masland, 2015; Werblin, 2011). Unlike most other areas of the central nervous system (CNS), the retina utilizes both GABA and glycine inhibitory neurotransmitters to refine glutamatergic excitatory signals (Franke & Baden, 2017; Werblin, 2011; C. …

Circuits For Active Vision : Parallel Tectothalamocortical Visual Pathways In The Mouse., Na Zhou

Electronic Theses and Dissertations

Vision is a critical sensation for the interaction between humans and their surrounding environment. The eyes connect with the brain via retinal ganglion cell axons, which transmit visual sensory information from the periphery into the central nervous system for further processing, eventually leading to visual perception and the visual guidance of movement. Two main targets of retinal axons are the superior colliculus (SC) and the dorsal thalamus. From the SC, visual information is conveyed to the dorsal thalamus, and from the dorsal thalamus visual information is conveyed to the cortex, striatum and amygdala. This dissertation is focused on the functional …

The Phenomenon Of Abstract Cognition Among Scholastic Chess Participants: A Case Study, Brent C. Laws

Electronic Theses and Dissertations

A qualitative investigation was conducted to explore the phenomenon of abstract cognition among a purposive sample of 5 secondary scholastic chess club participants. The case study enabled the researcher to explore the faculties of abstract cognition among students of contrasting skills and abilities in playing chess. The study also allowed for the consideration of potential visual-spatial, logical, academic, social competency and life benefits of chess play. Through analysis of interviews, chess simulations, blindfold chess play, and narration of chess lines and sequences, the investigator was able to extract meaning and code schemata into a holistic understanding of the phenomenon of …