Neuroscience and Neurobiology Commons^™

Testing P300-Based Biometric Authentication Paradigms, Jordan Razzak

Electronic Theses and Dissertations

Bench research suggests that P300 amplitude is greater in response to self-relevant stimuli compared to familiar stimuli. This effect could enable a novel method of biometric authentication based on the self-relevant P300. This dissertation aims to: (1) determine the optimal presentation paradigm for leveraging self-relevance in P300-based biometric authentication, and (2) investigate P300 responses from self-relevant stimuli versus stimuli learned over the course of a week.

Two presentation paradigms were compared – rapid serial visual presentation (RSVP) and matrix presentation (MP). Participant-specific RSVP and MP classifiers were trained by applying stepwise linear discriminant analysis to data collected during presentations of …

Examing Fear Conditioning/Extinction And The Role Of The Amygdala In Human Neuroimaging., Olivia Cook

Electronic Theses and Dissertations

Fear plays a crucial role in survival but can lead to psychological disorders when dysregulated. Fears can be innate due to evolutionary relevance or learned through associative processes, where predictive accuracy of threat is pivotal. Disruptions in fear neurocircuitry contribute to anxiety disorders, characterized by heightened activation and impaired learning. Fear conditioning and extinction paradigms based on classical Pavlovian conditioning have been used to study mechanisms underlying fear learning. Using this experimental model, fear networks in rodents have been described in detail with clear distinction between conditioning and extinction neural functioning. Yet, there is no consensus on the neurobiological processes …

Visualizing The Fretboard: Arpeggiated Patterns, Muscle Memory, And Neurocognitive Strategies For The 5-String Electric Bass, Matthew Alexander Woisin

Electronic Theses and Dissertations

Proficient navigation of the 5-string electric bass requires a comprehensive mastery of various techniques and a solid understanding of music theory. This includes a detailed grasp of arpeggios, chord extensions, and the development of deeply ingrained muscle memory for precise execution. This thesis introduces a structured methodology that refines existing fretboard visualization techniques and applies a unique manner of fretboard mapping, offering a more precise framework for comprehending and unlocking the full range of the instrument. By drawing insights from music theory, music education, cognitive science, neuroscience, and technology this approach is achieved by synthesizing research on visual pattern recognition, …

Integration And Modulation Of Visual Signals In Dorsal Thalamus., James Whitley

Electronic Theses and Dissertations

The visual thalamus is influenced by a diverse array of cortical and subcortical inputs that shape how information is transmitted to cortex. Using a variety of anatomical, optogenetic, and in vitro physiological techniques I investigated the differential impacts of modulation and integration of first and higher-order thalamic nuclei, while relying on influential concepts on the general organization of thalamic nuclei. In the first data chapter, I determined how GABAergic pretectum (PT) projections to the dorsal lateral geniculate nucleus (dLGN) and visual thalamic reticular nucleus (vTRN) can influence retinogeniculate signal transfer. We found that the PT provides over 75% of the …

Genetic Identification Of A Rapidly-Adapting Low-Threshold Mechanoreceptor Innervating Fungiform Papillae., Thomas Alexander Myers Ii

Electronic Theses and Dissertations

Mechanosensory innervation of the oral cavity enables us to detect the texture and location of the foods we consume. Our goal was to find a genetic identifier for a mechanoreceptive subtype. Toward this goal, we examined neurons expressing the neurotrophin receptor TrkC, parvalbumin (Pvalb), and the glutamate transporter Vglut3. Because different papilla types contribute to food detection in different ways, we examined the innervation patterns of these neuron subtypes. We found that Pvalb+ and Vglut3+ neurons were fungiform papilla specific, where TrkC innervated both papilla types. We examined the anatomy of the three genetic populations, finding that the Pvalb+ neurons …

Sensory And Motor Tectothalamic Circuits: Two Sides Of The Same Coin., Nazratan Naeem

Electronic Theses and Dissertations

Integration of sensorimotor information in the visual system has always been an intriguing topic to scientists, yet the subcortical sensory and motor circuits that are essential components of this process have remained elusive. In these studies, we used a blend of classical and contemporary techniques such as viral tracing, immunohistochemistry, optogenetics in-vitro whole cell electrophysiology, and electron microscopy in mice to characterize sensory and motor circuits of the superior colliculus (SC), a conserved visuomotor structure with connections with a wide variety of brain structures, including the thalamus. We focused on two SC cell types: visually responsive widefield vertical (WFV) cells …

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 …

Investigating The Impact Of Psychoactive Plant Alkaloids On Bumblebee Behavior, Skylar Mathieson

Electronic Theses and Dissertations

The relationship between plants and their pollinators is often framed as a food-for-service exchange in which plants provide pollinators with nutrients in exchange for transport of their gametes. However, in addition to essential nutrients, many floral rewards (nectar, pollen) also contain defensive toxins such as alkaloids, with largely unexplored consequences for plant-pollinator interactions. I investigated how three psychoactive and addictive plant alkaloids — caffeine, nicotine, and morphine — affect foraging behavior in generalist bumblebees (Bombus impatiens) using robotic flowers. Each of these chemicals affected pollinator foraging behavior, influencing the number and duration of their visits to flowers in …

Investigating The Role Of The Hypocretin/Orexin System In A Novel Model Of Polysubstance Dependence, Tyler Zarin

Electronic Theses and Dissertations

Substance use disorders (SUD) in the United States are steadily increasing. Potent and dangerous substances such as methamphetamine (MA) and fentanyl (FEN) are often co-used as a polysubstance (POLY), either intentionally or unknowingly as FEN is a common adulterant. SUD is characterized by physiological and psychological dependence involving the negative reinforcement of anhedonia and withdrawal which drive hypermotivated drug-taking behaviors. Current theory suggests that recruitment of hypocretin/orexin (HCRT) neuropeptide in reward and stress associated brain regions contributes to drug dependence. Despite strong evidence for HCRT’s role in mono-drug dependence, a relevant model for POLY dependence has yet to be developed, …

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 …

Unraveling The Role Of Hid-1: Insights Into Sgii Regulation, Breanna L. Sellers

Electronic Theses and Dissertations

The regulated secretory pathway is important for the secretion of hormones and neuropeptides from large dense core vesicles (LDCVs). Dysregulation of the biogenesis of LDCVs can result in metabolic and neurological diseases. Recent studies have suggested that the peripheral membrane protein HID-1 plays a role in the sorting and storage of granins which contribute to LDCV biogenesis. To further understand how HID-1 influences the regulation of granins, we investigated potential HID-1 interactors. We determined that while HID-1 is likely functioning in the same pathway as USP25, a deubiquitinating enzyme (DUB), the cause of reduced cellular SgII levels is likely not …

Emotional Content In Working Memory Processes: An Fmri Study., Manal Zafar

Electronic Theses and Dissertations

Working memory (WM) is a dynamic system that processes and manipulates both goal-relevant and goal-irrelevant information, integral to higher-level cognition and executive control (Fujii, 2001; Nyberg & Erikkson, 2016). The processing and manipulation of representations is modulated by the affective nature of the information (Pessoa, 2009) such that negative information can either impair or enhance WM processing. WM impairments are seen commonly across clinical disorders such as depression, anxiety, PTSD and schizophrenia (Levens & Gotlib, 2010; Joorman et a., 2011; Brodziak et al., 2015). Specifically, negative information is known to have differential processing in WM compared to neutral and positive …

Epidural Stimulation For Urogenital Dysfunction In The Spinal Cord Injured Rat., Natasha Lorraine Wilkins

Electronic Theses and Dissertations

Spinal cord injury (SCI) is a devastating, life changing event that greatly impacts quality of life. SCI can have body-wide, multi-system consequences including dysfunction within the urogenital system. Challenges with the urinary system include urinary incontinence, urine retention, and detrusor-sphincter dyssynergia all of which require maintenance through the regular use of catheters. Sexual dysfunction in men, who comprise nearly 80% of the SCI population, includes erectile dysfunction, anejaculation, retrograde ejaculation, poor expulsive force during ejaculation, and poor sperm quality. The treatment for sexual function in SCI men is focused more on fertility through the collection of sperm for insemination procedures …

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 …

Poly (Adp-Ribose) Polymerase-1 (Parp1) Expression In The Frontal Cortex And Hippocampus In Major Depressive Disorder (Mdd) And Suicide, Ramona Faith Fulkerson

Electronic Theses and Dissertations

Major Depressive Disorder (MDD) is a prevalent psychiatric disorder that has a complex pathophysiology. In this study we evaluate the expression of PARP1 and the downstream alarmin protein high mobility group box 1 (HMGB1) in two brain areas that have demonstrated pathology in MDD. MDD donors were compared to controls. MDD subgroups that died by suicide were also compared to those that did not die by suicide. Immunoblotting to determine PARP1 and HMGB1 protein expression was performed in white and grey matter from the frontal cortex and the hippocampus. In BA10 white and grey matter, PARP1 protein expression was significantly …

The Multipurpose Dna Repair/Redox Protein Ape1 In Rodent And Human Lewy Body Disease, Kristin Marie Miner

Electronic Theses and Dissertations

Lewy body disorders are a family of neurodegenerative conditions characterized by proteostatic and redox disequilibrium, leading to deposition of the abundant protein α-synuclein in hallmark inclusions and oxidative damage to DNA. Sublethal oxidative DNA damage in neurons is repaired predominantly by the base excision repair pathway, which involves the coordinated activity of several enzymes, including apurinic/apyrimidinic endonuclease 1 (APE1). Despite emerging connections between α-synuclein, oxidative stress, and DNA damage/repair, along with evidence demonstrating the multifunctional nature of APE1, the link between APE1 and α-synuclein has not yet been explored.

Here, we conducted a broad investigation of APE1 in the context …

The Effect Of Novel Microtubule Modulators On Experimental Lewy Body Disease, Anuj S. Jamenis

Electronic Theses and Dissertations

In Lewy body disorders, α-synuclein aggregates are believed to destabilize the microtubular framework. However, microtubules are a challenging therapeutic target, as excessive rigidity or flexibility afforded by microtubule modulators may be neurotoxic. Thus, the objective of the present study was to evaluate dual-acting microtubule- stabilizing/destabilizing agents in cellular and animal models of early-stage Lewy body disease.

In Aim 1 we tested the dual-acting tricylic pyrimido[4,5-b]indole analogs AG161-47 and AG161-41 in an in vitro preformed fibril induced model of Lewy body disease. We found that both compounds reduced preformed fibril-seeded α-synucleinopathy without toxicity in primary hippocampal cultures. AG161-47 subtly impacted microtubule …

Perinatal Buprenorphine Effects On Offspring Growth, Opioid Withdrawal, And Brain Morphology In Rats, Parker Barnes

Electronic Theses and Dissertations

Opioid use disorder (OUD) impacts 5.6 million people in the US. Buprenorphine (BUP) is a commonly prescribed opioid medication used to treat OUD, including in pregnant women. However, opioid use during pregnancy is associated with poorer infant outcomes including reduced fetal growth, neurodevelopmental deficits, and neonatal opioid withdrawal syndrome (NOWS). Recent clinical data suggests that providing mothers with a lower dose of BUP may result in fewer negative outcomes in infants. Here, a preclinical rodent model of low-dose perinatal BUP exposure was used to study offspring health outcomes in the neonate, juvenile, and adolescent offspring. Dams were given clinically relevant …

Exploring Resilience With Neuroimaging: Moderators Of The Impacts Of Childhood Traumatic Stress On Fear Processing., Karisa June Hunt

Electronic Theses and Dissertations

Childhood trauma is an alarming public health crisis, and the field of trauma research is relatively underdeveloped given population rates of childhood trauma and post-trauma pathology. Even less studied than the impacts of trauma are the impacts of resilience, and the protective factors that foster it. It is widely acknowledged that an investigation of trauma is incomplete without an investigation of its impacts on fear processing. Understanding the neural underpinnings of resilience to childhood trauma during fear conditioning is vital to the development of therapeutic interventions able to moderate its devastating impacts. The present study investigated the complex neurobiological interplay …

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 …

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 …

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 …

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 …

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 …

Evaluating Sex Differences In The Neuroimmune Response Following Neuroinflammation And Relief Due To Nanotheranostic Treatment, Brooke Deal

Electronic Theses and Dissertations

Until recently, the majority of preclinical neuroinflammatory studies were performed on males. Because of this, less is known about the female neuroinflammatory response to injury, formation of pain, or response to pain-relieving therapies. The neuroinflammatory response is multifaceted with neuronal, glial, and immune cells all contributing to the induction and resolution of neuroinflammation. During this response, macrophages typically undergo an upregulation of cyclooxygenase-2 (COX-2) leading to the production of prostaglandin E2 (PGE2), which is linked to neuronal sensitization and pain. Non-steroidal anti-inflammatory drugs (NSAIDs) attenuate PGE2 by the inhibition of COX-2. A limitation with NSAIDs is that due to the …

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 …

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 …

The Reinforcement Enhancing Effects Of Delta-9-Tetrahyrdrocannabinol (Thc) In Male And Female Rats, Kynah Walston

Electronic Theses and Dissertations

Cannabis is widely consumed by humans for pharmacological effects that are mediated by THC, though there is little evidence that THC is a primary reinforcer in non-human animal models. We hypothesized that THC may have potent reinforcement enhancing effects, comparable to other drugs (e.g., nicotine and caffeine) which are also widely consumed by humans, but difficult to establish as primary reinforcers in non-humans. In three experiments with male and female rats saccharin (SACC) or a visual stimulus (VS) served as reinforcers for operant behavior. We explored several pharmacological parameters of THC on responding for SACC or VS, including THC dose, …

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 …