Neuroscience and Neurobiology Commons^™

P300 Event-Related Potential Responses To Self-Relevant Stimuli, Jordan Razzak

Electronic Theses and Dissertations

Previous literature has suggested an apparent P300 sensitivity to self-relevant stimuli. To further explore this relationship, we asked participants to submit 10 photos, each of a particular category (e.g. footwear, plants), to be used as either targets or distractors in a given condition of an oddball task. Furthermore, we attempted to see whether the effect of self-relevance on the P300 could be induced in a participant by allowing them to study a set of unique photos which would then be used as targets. Our analysis suggested that P300 amplitude elicited in response to self-relevant stimuli used as targets was statistically …

Exploring Available Information On The Gut-Brain Axis And Alzheimer’S Disease For Clinicians Making Dietary Recommendations: A Scoping Review, Megan Gibson

Electronic Theses and Dissertations

Abstract: Alzheimer’s Disease (AD) is a complex neurodegenerative disease that requires interprofessional collaboration. Pharmacological options are currently ineffective, increasing the need for preventative strategies to combat the rise of AD. Considerations of gut-targeted interventions have increased as a key component in the prevention of AD, based on the understanding that the state of the gut microbiome can impact cognitive function through the pathway known as the gut-brain axis.

Methods: This scoping review explored information on the gut-brain axis in persons with AD. A comprehensive search was conducted in November 2023. Forty reviews and 13 human studies were analyzed.

Results: There …

Using A Toxic Aging Coin To Assess Hexavalent Chromium-Induced Neurotoxicity., Samuel Thomas Vielee

Electronic Theses and Dissertations

We are facing an aging crisis, with 20% of the U.S. population projected to be geriatric (65+) by 2030 and live another 40+ years. Age-related diseases accompany a growing geriatric population, emphasizing the need to understand their etiology. Environmental pollutants compound this crisis by: 1) geriatrics are more susceptible, exacerbating age-related diseases and comorbidities, and 2) they accelerate biological aging, inducing age-related diseases at younger ages. We address this crisis using a ‘toxic aging coin’ approach; heads examines how age impacts toxicity, tails examines how chemicals accelerate aging. This thesis applies the heads side for Cr(VI)-induced neurotoxicity across ages. We …

Connectivity Of Amygdala Somatostatin-Expressing Neurons And Their Role In Taste-Guided Behavior., Jane Jeruto Bartonjo

Electronic Theses and Dissertations

The nucleus of solitary tract (NST) and parabrachial nucleus (PBN) represent the first and second central synapses of ascending gustatory information. Neural processing in these nuclei is influenced by descending input from forebrain regions such as the central nucleus of the amygdala (CeA). In mice, we have shown that somatostatin (Sst) expressing neurons of CeA that project to NST and PBN are largely distinct cell populations and optogenetic inhibition of the CeA/Sst-to-NST subpopulation increases the intake of high concentrations of quinine with no apparent effect on sucrose intake. Synaptic connectivity of these cells is needed to understand the possible mechanisms …

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 …

Artificial Dendritic Neuron: A Model Of Computation And Learning Algorithm, Zachary Hutchinson

Electronic Theses and Dissertations

Dendrites are root-like extensions from the neuron cell body and have long been thought to serve as the predominant input structures of neurons. Since the early twentieth century, neuroscience research has attempted to define the dendrite’s contribution to neural computation and signal integration. This body of experimental and modeling research strongly indicates that dendrites are not just input structures but are crucial to neural processing. Dendritic processing consists of both active and passive elements that utilize the spatial, electrical and connective properties of the dendritic tree.

This work presents a neuron model based around the structure and properties of dendrites. …

Perineuronal Nets Are Not Required To Close The Critical Period For Ocular Dominance Plasticity., Emily Crouse

Electronic Theses and Dissertations

In the developing visual system, a transient critical period demarcates when neural circuits are most sensitive to visual experience. In the mouse, the critical period occurs between approximately postnatal day(P) 19 to 32. Closing one eye (monocular deprivation, MD) within the critical period shifts ocular dominance (OD) to be more responsive to the open eye. Nogo-66 Receptor 1 (NGR1) limits OD plasticity to the critical period yet it remains unknown how OD plasticity propagates through primary visual cortex or by which mechanisms NGR1 utilizes to confine said plasticity. In primary studies, NGR1 was selectively deleted in different cortical layers to …

An Investigation Into Structural Plasticity In Peripheral Taste Neurons Associated With Taste Cell Turnover., Zachary Whiddon

Electronic Theses and Dissertations

The continual replacement of taste cells creates interesting questions regarding how the innervating neurons are impacted during this process. Here we ask how innervation within taste buds is affected when taste cell entry is inhibited and reestablished. Inhibition of sonic hedgehog signaling (Shh) is thought to inhibit taste cell turnover. Consistently, fewer new cells were added to individual taste buds after treatment with a Shh-inhibitor compared to vehicle treatment, and taste bud volume decreased after 16 days of treatment. We next examined how taste nerve fiber extension into the gustatory epithelium is affected by preventing taste cell turnover. Ten days …

Synaptic Properties Of Parabigeminal Circuits., Kyle Whyland

Electronic Theses and Dissertations

Subcortical structures of the visual system have been the subject of intense study in recent years, but there remain some important unanswered questions regarding the synaptic relationships linking the nuclei that comprise this important sensory network within the brain. In these studies, we use several modern and traditional approaches, including viral tract tracing, in vitro slice physiology, immunohistochemistry, optogenetics, and electron microscopy to characterize the circuits linking the superior colliculus (SC), parabigeminal nucleus (PBG), and lateral geniculate nucleus (LGN), with particular focus on GABAergic and cholinergic cell types. We found that the SC, an important visuomotor structure with connections to …

Supraspinal Reorganization After Pediatric-Onset Spinal Cord Injury., Luis Alvarado

Electronic Theses and Dissertations

Pediatric spinal cord injury (SCI) disrupts the efferent and afferent flow of the developing brain, leading to devastating functional impairments below the injury site, yet our understanding of its impact on the brain remains limited. This study examines supraspinal reorganization in children with SCI using electrophysiology and neuroimaging techniques to understand the relationship between residual spinal transmission and supraspinal reorganization. Chapter 2 discusses the development of a child-centric approach using ‘learn, play, and practice’ to foster a trusting relationship with each child and increase compliance with experimental protocols. Chapter 3 evaluates the residual neural transmission of three spinal pathways in …

Chemosensory Processing By The Mediodorsal Thalamus., Kelly Fredericksen

Electronic Theses and Dissertations

The mediodorsal thalamus (MD) is thought to be key component of the network that processes chemosensory information to guide our consummatory choices. Previous studies show that the mediodorsal thalamus receives projections from both the piriform cortex (PC) and gustatory cortex (GC), suggesting that it may process chemosensory information from both areas. Although the mediodorsal thalamus has been shown to respond to odors detected by sniffing, it remains unknown how its neurons represent experienced odors, tastes, and odor-taste mixtures originating from the mouth. Importantly, humans and animals with mediodorsal thalamic lesions do not suffer from anosmia, but experience deficits in odor …

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 …

Telomerase Reverse Transcriptase Marks A Novel Population Of Adult Stem Cells In The Mouse Brain That Respond To Metabolic Interventions By Modulating Adult Brain Plasticity, Gabriel S. Jensen

Electronic Theses and Dissertations

Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (qASC) in numerous adult murine and human tissues but has never been explored in the adult brain. Here, these data demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent qASCs. TERT+ cells were localized to numerous classical neuro/gliogenic niches including the ventricular-subventricular zone, hypothalamus and olfactory bulb, as well as newly discovered regions of adult tissue plasticity such as the meninges and choroid plexus. TERT+ cells expressed neural stem cell markers such as Nestin and Sox2, but not markers of activated stem/progenitor cells, …

Genetic Determinants Of Primary Nociceptor Sensitivity In Drosophila Melanogaster, Christine Hale

Electronic Theses and Dissertations

Abnormal pain affects ~50 million adults nationwide. With many of the current treatment options for chronic pain, such as opioid analgesics, carrying side effects such as the threat for addiction, research into safer and more effective options for chronic pain relief is crucial. Abnormal alterations in nociceptive sensitivity, which is the sensitivity of peripheral sensory neurons that detect noxious stimuli, can underlie, and perpetuate chronic pain. However, much is still unknown about the mechanism of how these abnormal alterations in sensitivity occur. To help elucidate genetic components controlling nociceptive sensitivity, the Drosophila melanogaster larval nociception model has been used …

Neural Stem Cells: Age-Dependent Outcomes During Viral Infections In The Central Nervous System, Manisha N. Chandwani

Electronic Theses and Dissertations

Viral infections in the central nervous system (CNS) are associated with neurodevelopmental and neurobehavioral deficits. The outcomes of viral infections can be driven by damage and death of neurons. Neural stem cells (NSCs) play key roles in neurodevelopment, repair, and physiological brain function. During a viral infection, NSC activity can disturbed by direct infection of NSCs by the virus or by anti-viral immune response. Here, we aimed to assess whether the anti-viral immune response can impact NSC activity during an immunocompetent response in the adult brain. We utilized a transgenic mouse model of Measles virus infection where only the CNS …

Validation Of The 40 Hz Auditory Steady State Response As A Pharmacodynamic Biomarker Of Evoked Neural Synchrony, Muhammad Ummear Raza

Electronic Theses and Dissertations

Schizophrenia is a troubling and severe mental illness that is only incompletely treated by currently available drugs. New drug development is hindered by a scarcity of functionally relevant pharmacodynamic biomarkers that are translatable across preclinical and human subjects. Although psychosis is a major feature of schizophrenia, cognitive and negative symptoms determine the long-term functional outcomes for patients. Stimulus-evoked neural synchrony at gamma (~ 40 Hz) frequency plays an important role in the processing and integration of sensory information. Not surprisingly, schizophrenia patients show deficits in gamma oscillations. NMDA receptor (NMDAR) activation on fast-spiking parvalbumin-positive interneurons is deemed important for the …

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 …

Hypocretin-Receptor Mrna Expression In The Central Amygdala Of Alcohol-Dependent And Non-Dependent Rats, Gabriel Aldridge

Electronic Theses and Dissertations

Hypocretin/Orexin (HCRT) neurotransmission facilitates drug-seeking behavior. HCRT neurotransmission at HCRT-receptors 1 and 2 (HCRT-R1 and -R2, respectively) is implicated in addiction. During the shift to alcohol-dependency, adaptations in neurotransmitter systems occur in reward- and stress-related brain regions. Specifically, neurotransmission systems in the central amygdala (CeA) are modulated by alcohol drinking/exposure. Therefore, this study investigated Hcrtr1 and Hcrtr2 mRNA expression in the CeA of alcohol-dependent rats and in non-dependent controls during acute alcohol withdrawal. Fos mRNA expression in the CeA of alcohol-dependent and non-dependent rats was also determined to assess adaptations in neuronal activation. To our knowledge, this is the first …

Early Detection Of Atypical Motor And Neurobehavior Of Infants At Risk Secondary To Opioid Exposure: A Prospective Study, Kara Boynewicz

Electronic Theses and Dissertations

Prenatal opioid exposure has been studied in relation to infants' medical outcomes. However, large gaps exist in the literature supporting early identification of atypical neurobehavior and motor development of infants with prenatal opioid exposure. The purpose of the study was to investigate whether prenatal opioid exposure has a negative influence on a newborn infant’s neurobehavior and motor development to aid in the early identification of potential delays. Using a prospective quasi experimental design, infants motor development using the Test of Infant Motor Performance (TIMP) and neurobehavior using the NICU Neonatal Network Scale (NNNS) was assessed on 58 infants in a …

Behavioral Effects And Neurobiological Mechanisms Of 3-Aminobenzimide In A Rodent Model Of Chronic Psychological Stress, Liza Wills

Electronic Theses and Dissertations

Major depressive disorder (MDD) is a leading cause of disability worldwide, with a lifetime prevalence rate of approximately 20%. Inadequate pharmacological treatment methods for MDD are a significant debilitating factor. Patient estimates suggest that the treatment resistance rate for pharmacological interventions is over 30%. Postmortem analyses of human tissue of individuals diagnosed with MDD have shown an increase in Poly (ADP-ribose) polymerase 1 (PARP-1) mRNA gene expression in prefrontal cortical white matter when compared to psychiatrically normal brain tissue. In order to further investigate this issue, the present study used the social defeat stress/chronic unpredictable stress (SDS + CUS) rodent …

The Pathophysiological Mechanisms Of Alzheimer's Disease; Investigating Therapeutic Interventions For Disease Onset, Alexandra A. Sandberg

Electronic Theses and Dissertations

Alzheimer’s Disease is a multifarious disease that progressively affects more people as both the proportion of older adults in the population and life expectancy increase in both the United States and worldwide. This devastating disease is a result of rampant neuronal loss in the memory centers of the brain that robs the independence of those who are diagnosed and places a heavy burden on those who care for them. Traditionally speaking, research has focused on the hallmark pathology of amyloid plaques, targeting them to try and prevent disease onset. However, countless failures in clinical trials aimed at this said pathology …

Cgrp-Driven Lateralization Of Pain Modulation By The Central Amygdala, Heather Allen

Electronic Theses and Dissertations

The central amygdala (CeA) is a bilateral, mid limbic brain region involved in the processing of pain and emotion. Interestingly, the left and right CeA are functionally lateralized in the context of bladder pain, with the left and right CeA having opposing effects on bladder pain-like behavior. However, the specific mechanisms driving these divergent functions are unknown. Nociceptive signals from the bladder are relayed to the CeA via projection neurons in the parabrachial nucleus (PBN) that express high levels of calcitonin gene-related peptide (CGRP). In these studies, we investigated the influence of PBN CGRP signaling in the left and right …

Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally

Electronic Theses and Dissertations

Cellular microenvironment or cell niche plays an important role in developmental biology and disease pathophysiology. Physical or chemical signals in microenvironment drive the cellular activity. These signaling molecules are generated from the surrounding cells/tissues as part of intercellular communication; a fundamental property of a cell. Dynamic profile of these signaling molecules in the microenvironment plays a pivotal role in transfer of molecular information from cell to cell in disease proliferation or fate determination. Recapitulating these signaling cues in an in vitro study is difficult to achieve using standard cell culture techniques. However microfluidic systems are capable of addressing these issues, …

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 …

Bioacoustic Studies Of Population Size And Microdialects In An Island-Living Savannah Sparrow Population, Abby Lynn Jill Hensel

Electronic Theses and Dissertations

Bioacoustic monitoring provides an innovative technique for studying the behaviour and ecology of wild birds. In this thesis I use bioacoustic monitoring as a tool for studying Savannah Sparrows (Passerculus sandwichensis). In my first data chapter, I tested the accuracy of passive acoustic monitoring in estimating population size and annual survival in an island population of Savannah Sparrows. Six years of data reveal that passive acoustic monitoring with autonomous recorders provides accurate underestimates of population size and annual survival. I found that passive acoustic monitoring estimated population size with 74% accuracy, with higher accuracy in low density years. I also …

Gabaergic-Related Pathology In The Anterior Cingulate Cortex Of Postmortem Human Brain Tissue In Autism Spectrum Disorder, Gethien Andrew

Electronic Theses and Dissertations

The anterior cingulate cortex (ACC) is part of the cognitive and emotional brain circuitry that mediates social interaction. Imbalances between inhibitory, GABAergic neurons, and excitatory, glutamatergic neurons, in this region are essential to brain circuity during social responses and are thought to be involved with behaviors associated with autism spectrum disorder (ASD). Enriched cell populations of glutamatergic neurons, obtained through laser capture microdissection, were used for gene expression studies of GABAergic receptors (GABRA1, GABRA4, and GABBR1). Additionally, proteins that impact GABAergic synapses (Spinophilin, CPLX1, mTOR, IGF1R, PSD95, PARP1) were investigated using Western Blotting with punchdissected homogenate brain tissue from ACC …

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 …

Translational Fidelity And Its Role In Neuronal Homeostasis, Markus Terrey

Electronic Theses and Dissertations

The process of translation, which refers to decoding genetic information from mRNA to protein, is vital for all cellular function. Translational fidelity starts at the level of aminoacylation of transfer RNAs (tRNA). This reaction is catalyzed by aminoacyl tRNA synthetases where each amino acid is transferred to its corresponding cognate tRNA. Because tRNAs harbor the anticodon sequence to decodes a particular mRNA codon, the specific aminoacylation of the tRNA with a cognate amino acid establishes the rules of decoding genetic code into proteins. Aminoacylated tRNAs are then delivered to ribosomes, where ribosomes in a highly organized manner need to accurately …

The Neural Architecture Of Emotional Intelligence., Teodora Stoica

Electronic Theses and Dissertations

Emotional Intelligence (EI) is a nebulous concept that permeates daily interpersonal communication. Despite prolific research into its benefits, EI subjective measurement is difficult, contributing to an enigmatic definition of its core constructs. However, neuroimaging research probing socioaffective brain mechanisms underlying putative EI constructs can add an objective perspective to existing models, thereby illuminating the nature of EI. Therefore, the primary aim of this dissertation is to identify brain networks underlying EI and examine how EI arises from the brain’s functional and structural neuroarchitecture. EI is first defined according to behavioral data, which suggests EI is made up of two core …