Neuroscience and Neurobiology Commons^™

Gpu-Based Electromagnetic Microwave Tomography For Brain Imaging And Stroke Detection, Pablo Sotelo Torres

Open Access Theses & Dissertations

Each year, an estimated 795,000 people in the U.S. suffer a stroke, with approximately 610,000 being first-time cases. Of these, 87% are ischemic strokes, while the remaining 13% are hemorrhagic. Current imaging methods, such as Computed Tomography (CT), Positron Emission Tomography (PET), and Magnetic Resonance Imaging (MRI), provide useful information into brain tissue properties; while each technique has its advantages, they remain expensive, non-portable, and often too slow for emergency bedside or in-ambulance use. Electromagnetic Microwave Tomography (EMT) offers a promising alternative: an affordable, portable, rapid, and safe method for stroke detection. By contrasting dielectric properties between healthy and affected …

Enduring Efffects Of Juvenile Fluoxetine Exposure On Serotonin Transporter Expression Within The Hippocampus And Prefrontal Cortex Of Male C57bl/6 Mice, Daniel Eduardo Calvo

Open Access Theses & Dissertations

Prescription rates of fluoxetine, the most dispensed selective serotonin reuptake inhibitor, have been rising among the juvenile population. Since adolescence is a critical developmental period in which the brain undergoes pruning, chronic increases in serotonin levels may lead to long-term neurobiological changes in brain regions responsible for emotional regulation. Thus, using mice as a model system, this thesis evaluated how adolescent fluoxetine exposure (AFE) influences the expression of serotonin transporters (SERT) in the adult hippocampus and prefrontal cortex. To do this, postnatal day (PD)-35 male C57BL/6 mice were administered with fluoxetine (250 mg/l in their drinking water) for 15 consecutive …

Characterization Of Glyt1 Expression And Glycinergic Circuits, Laura Patricia Montes

Open Access Theses & Dissertations

Glycine is one of the main inhibitory neurotransmitters in the central nervous system. Glycine is regulated by the glycine transporters 1 and 2 (GlyT1 and GlyT2, respectively) in the synaptic cleft. Both transporters participate in glycinergic inhibitory neurotransmission. Moreover, GlyT1 also participates in glutamatergic excitatory neurotransmission. GlyT2 is devoted to caudal regions of the brain and is used as a marker for glycinergic neurons. In contrast, GlyT1 is expressed across the brain in the rostrocaudal axis and is highly associated with GlyT1-positive glial cells. Data from our laboratory has identified GlyT1-positive neurons in the rodent brain. Therefore, we hypothesize that …

Expression Of Glycine Transporter 1 In The Rodent Basal Ganglia: Glial Vs. Neuronal, Rosa Atziri Perez

Open Access Theses & Dissertations

Glycine functions as an inhibitory neurotransmitter in the central nervous system (CNS),and it is mainly involved in autonomic functions. The levels of extracellular glycine are regulated by two membrane transporters, glycine transporter 1 and glycine transporter 2 (GlyT1 and GlyT2, respectively). These transporters differ in function and localization within the CNS. For many years, studies suggested that only GlyT2 served as a neuronal marker; however, GlyT1 has been localized in neurons in recent studies. The expression of GlyT1 is widespread compared to GlyT2; hence, the main objective is to determine the nature of the expression of GlyT1 in areas devoid …

The Bullied Prairie Vole: Modeling Depression And Anxiety Through Social Defeat Stress, Minerva Rodriguez

Open Access Theses & Dissertations

Stress-induced illnesses, such as major depression and anxiety, are significant global causes of disability. This highlights the need for reliable animal models that accurately mimic social stress-induced maladaptations, thus, allowing the experimental study of the etiology of such disorders. Prairie voles (Microtus ochrogaster), known for their human-like bi-parental behavior and monogamous partner preferences, are a relevant model for the study of stress-induced psychopathologies. For this reason, in this dissertation, I examined whether exposing voles to the social defeat stress (SDS) paradigm, an experimental approach that captures bullying behavior, would result in both depression and anxiety-related profiles. To do this, experimental …

Investigating Brain Reward Mechanisms: A Comparative Study In Male And Female Rats, Valeria Garcia

Open Access Theses & Dissertations

Drug addiction is a serious public health concern. Recently, electronic cigarette use has become increasingly popular among vulnerable populations such as adolescents and women. Previous research on conventional cigarette use has shown significant sex differences in drug-seeking behavior and withdrawal symptoms, which are driven mainly by hormonal differences. However, changes in sex hormones do not completely explain the enhanced reward sensitivity reported in females. Thus, this dissertation aims to examine other alternative reasons that can explain these sex differences, such as differences in reward-seeking and neuronal reactivity. Additionally, there is a dearth of consistency across papers intending to map electrode …

Examination Of The Role Of Ovarian Hormones On Nicotine Withdrawal Severity In Females, Priscilla Giner

Open Access Theses & Dissertations

Women are more susceptible to the long-term consequences of chronic nicotine exposure, and clinical evidence has shown that abstinence from nicotine exposure produces a withdrawal syndrome that is intensified by estrogen (E2 in rats) and progesterone (PR) in females. The goal of this Masterâ??s thesis was to determine the mechanisms by which E2 and PR promote withdrawal from nicotine vapor inhalation in female rats. Prior work in male rodents has revealed that nicotine withdrawal is modulated in the medial habenula-interpeduncular nucleus (MHb-IPN) pathway. Our hypothesis is that females experience greater inhibition of the IPN via local interneurons that release the …

Examination Of The Effects Of Various Pharmacotherapies For Diabetes On Nicotine Intake And Pain Sensitivity, Sebastian Ortegon

Open Access Theses & Dissertations

Tobacco use and diabetes are major public health concerns. Prior work has suggested that persons with diabetes may exhibit greater susceptibility to nicotine dependence, and treatments for nicotine cessation are less effective. From existing literature, it is also unclear if neuropathic pain contributes to nicotine use in persons with diabetes. To address these issues, this Masterâ??s thesis first assessed the efficacy of diabetes pharmacotherapies on nicotine intake, food consumption, and water intake in rodent models of insulin resistance (Aim 1). Subsequent studies assessed the impact of analgesic medications on nicotine intake and neuropathic pain in rodent models that produce neuropathic …

Decision-Making In Rats: Effects Of Drug Abuse, Safa Binte Hossain

Open Access Theses & Dissertations

Decision-making is a critical cognitive function, often impaired by substance abuse. Understanding the underlying mechanisms in both human and animal models is essential for developing effective treatments. This thesis aims to study approach-avoid decision-making in rats and focuses on the impacts of oxycodone self-administration and alcohol abuse on approach-avoid decision-making.We hypothesize that oxycodone self-administration will alter decision-making in female rats, revealing sex differences and distinct psychometric functions, alcohol habituation will similarly affect decision-making in male rats. The study involved 23 Long Evans rats (11 males and 12 females) for decision-making behavioral study connecting multiple levels of rewards and costs combinations. …

Fighting For A Health Diagnosis: An Autoethnographic Journey Into The Role Of Access And Limitations Of Resilience In The Face Of Poverty, Josette Pelatan

Open Access Theses & Dissertations

This research represents a highly personalized account of the complexities, interpretations, and reflections of the journey of a doctoral student navigating the challenges of health through access on a U.S.-Mexico border. Using myself as the subject and the researcher in the social context of schooling provided the impetus for this self-study. Through an insider’s vantage point, I have chronicled and traced the experiences of my own identities’ transitions and multilayered intersectionality using the qualitative methodology of autoethnography. This genre of qualitative research brings the reader closer to the subculture studied through the author’s experiences.

While every story has its unique …

Atlas-Based Analysis Of The Neural Projections From The Lateral Hypothalamic Area To The Lower Brainstem In The Adult Male Rat, Jessica Valeria Salcido Padilla

Open Access Theses & Dissertations

Within the last decade, the number of diseases associated with dysregulation of the neural circuits responsible for energy balance, glucosensing, and feeding control has increased. One brain region containing these circuits is the lateral hypothalamic area (LHA), which plays an important role in the sleep/wake cycle, energy balance, and motivated behavior. Although the LHA has been termed a â??feeding centerâ??, other regions within the hindbrain are known for the regulation of similar functions including energy balance, glucosensing, and feeding control. While many studies have explored and reported projections from the LHA to the hindbrain, few have further investigated the interconnections …

Metrics For Comparison Of Complex Networks, Clarissa Reyes

Open Access Theses & Dissertations

Heuristic network statistics are used as a preliminary approach to identify change across networks. In networks where there is known node correspondence (KNC), conventional network comparison methods include taking a norm of the difference matrix, or calculating dissimilarity measures like DeltaCon and cut distance. Since different KNC measures provide varying insight to the network comparison problem, we propose employing Rank Score Characteristic Functions (RSCFs) and the rank-score process as a method for reaching a consensus when ranking quantified change across multiple pairs of networks â?? which is particularly useful for ranking change across subpopulations or subgraphs. Additionally, we propose a …

Neural Damage Following Francisella Tularensis Infection, Anahis Tena

Open Access Theses & Dissertations

This dissertation investigates the impact of Francisella tularensis infection on the brain, focusing on its anatomical localization, effects on synaptic health, and behavioral and cognitive consequences in mice. Employing a combination of fluorescent tagging, confocal and light sheet microscopy, the study first maps bacterial foci within the brain, anticipating a concentration in the limbic system, particularly the hippocampus. Subsequently, it examines synaptic function post-infection using calcium imaging in various neuronal cultures, expecting a decrease in calcium signaling indicative of synaptic impairment. Finally, behavioral assays like the forced swim test, object recognition test, and Morris Water Maze assess the cognitive and …

Long-Term Effects Of Juvenile Ketamine And/Or Social Stress Exposure On Spatial Memory Performance In C57bl/6 Mice, Israel Garcia Carachure

Open Access Theses & Dissertations

Ketamine is administered to manage major depressive disorder in adolescent patients. However, the long-term effects of juvenile ketamine exposure on memory-related tasks have not been thoroughly assessed. Thus, we examined whether exposure to ketamine, psychological stress, or both, results in long-lasting alterations in spatial memory in C57BL/6 mice. Furthermore, we evaluated how ketamine and/or psychological stress history influenced hippocampal protein kinase b¬–mammalian target of rapamycin (AKT-mTOR)-related signaling, since this molecular cascade is associated with ketamine’s acute/fast-acting antidepressant properties. Male and female postnatal day (PD)-35 mice underwent 10-days of vicarious defeat stress (VDS), a form of psychological stress, with or without …

A Novel Neuroinvasive Infection Modality For Francisella Tularensis Elicits Neuroinflammation Resulting In Cellular Damage, Mireya Griselle Ramos-Muniz

Open Access Theses & Dissertations

Francisella tularensis (Ft.) is a gram-negative coccobacillus bacterium that causes the zoonotic disease tularemia in humans. Ft. causes the most severe, often fatal, form of the disease through inhalation. However, Ft. is most commonly transmitted through direct contact with infected animal carcasses such as rodents and rabbits, consumption of contaminated food or water, or through arthropod bites, particularly ticks. Due to its extremely low infectious dose, high mortality rate, and potential use as a biological warfare agent, Ft. is classified by the CDC as a "Tier 1 select agent". Ft. infection triggers an overactive inflammatory response, termed a "cytokine storm", …

Connectional Analysis Of Brain Regions Associated With Feeding, Kenichiro Negishi

Open Access Theses & Dissertations

Rodent models are invaluable for understanding the foundations of motivatedbehaviors. One major obstacle faced by these efforts is the lack of a 'wiring diagram' or a 'parts list' of structures that support motivated behaviors. Here, I present work that advances our knowledge of the structural organization of connections and chemoarchitecture of the diencephalon. Chapter 1 aims to clarify a wiring diagram of the medial prefrontal cortex (mPFC) following a recent demonstration of cortically-evoked feeding through this region. Chapter 2 clarifies the distributions of a subpopulation of tyrosine hydroxylase (TH) neurons in the hypothalamus. These disparate datasets were analyzed and interpreted …

Characterization Of Potential Genes Encoding For A Glycine Transporter From Drosophila Melanogaster, Denise Avalos

Open Access Theses & Dissertations

The study of glycine transporters has been neglected compared to other members of the Solute Carrier 6 (SLC6) family of proteins, such as the dopamine and serotonin transporters, even though they are just as crucial to survival. However, glycinergic neurotransmission has been extensively studied in mammals, resulting in vast, valuable information. The same cannot be said for invertebrates, however. In this study, we aim to establish an initial first step in elucidating components of glycinergic neurotransmission in the invertebrate, Drosophila melanogaster. We believe this organism possesses a glycine transporter because a glycine receptor has been identified and characterized. Specifically, we …

Neurogenetic Function Of Host Cell Factor-1, Victoria Lynn Castro

Open Access Theses & Dissertations

Neural precursor cells (NPCs) are the stem-like cells of the developing brain. These cells differentiate into the differentiated cell types of the central nervous system. If disruption occurs in the number of total NPCs formed or their survival, various disorders including learning disabilities, behavioral problems, or epilepsy can occur. This dissertation describes how the HCFC1 gene controls the proliferation and differentiation of NPCs. HCFC1 encodes for a transcriptional co-factor that regulates the growth and metabolism of stem cells, including NPCs. Mutations in HCFC1 cause cblX syndrome, a neural developmental disorder that affects the nervous system and causes microcephaly, epilepsy, and …

Region Detection & Segmentation Of Nissl-Stained Rat Brain Tissue, Alexandro Arnal

Open Access Theses & Dissertations

People who analyze images of biological tissue rely on the segmentation of structures as a preliminary step. In particular, laboratories studying the rat brain delineate brain regions to position scientific findings on a brain atlas to propose hypotheses about the rat brain and, ultimately, the human brain. Our work intersects with the preliminary step of delineating regions in images of brain tissue via computational methods.

We investigate pixel-wise classification or segmentation of brain regions using ten histological images of brain tissue sections stained for Nissl substance. We present a deep learning approach that uses the fully convolutional neural network, U-Net, …

Morphine-Induced Tolerance Is Reduced By The Consumption Of A Ketogenic Diet, But Not A High Fat/High Carbohydrate Diet, Nina Beltran

Open Access Theses & Dissertations

Opioid drugs like morphine are used medicinally for pain relief, but also have abuse liability that can lead to opioid use disorder (OUD), which contributes to nearly 70% of drug overdose deaths in the United States. Another rising health concern is the global obesity epidemic, and new evidence suggests that obesity and OUD might converge to impact individuals. For example, high body mass index (BMI) is associated with greater reports of pain among women. Further, opioid overdose risk is increased among individuals diagnosed with obesity, suggesting a potential relationship that might convey enhanced vulnerability among some populations. Given the high …

Sex And Age Differences In Approach Behavior Toward A Port That Delivers Nicotine Vapor, Veronika Evangelina Espinoza

Open Access Theses & Dissertations

The goal of our laboratory is to study the mechanisms that promote nicotine use, particularly in vulnerable populations such as adolescents and females. Thus, the purpose of this thesis was to characterize age and sex differences in the motivational/rewarding effects of nicotine (Aim 1) and withdrawal behavior (Aim 2). To more closely model human use patterns, the present study employed nicotine vapor methods involving passive exposure for 14 days in adolescent and adult female and male rats. Age and sex differences in approach behavior (nosepokes) were assessed in a port that delivered nicotine plumes on Day 1 and 14. Controls …

Impact Of Xenobiotics On Neuronal Outcomes, Gabriela Henriquez

Open Access Theses & Dissertations

Neurodegenerative diseases are a common affliction of the Central Nervous System. They are caused by age, genetics, and environmental factors. Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic Lateral Sclerosis are well-known among the host of neurodegenerative disorders, with Alzheimer's disease and Parkinson's disease being the leading pathologies across this canvas. It is known that the pathogenesis of neurodegenerative diseases is multifactorial due to the involvement of genetic mutations, radical-induced protein damage, abnormal aggregation of misfolded proteins, and the formation of amyloid deposits. The amyloid proteins in neurodegenerative disease include Tau and Amyloid (Aβ) in Alzheimer's disease and α-Synuclein in …

Transgenerational Differences Between Two Culturally Distinct Prairie Vole Populations, Richard Joaquin Ortiz

Open Access Theses & Dissertations

Culture can be described as a system of environmental beliefs, values, and social practices within one’s environment. This system is passed on from generation to generation and provides a basis for an individual’s behaviors and cognitive perceptions. Cultural neuroscience is an emerging field that intertwines domains of anthropology, psychology, neuroscience, and genetics to help understand the underlying processes, neural mechanisms and genomic factors that vary across cultures. Similar to humans, the socially monogamous prairie vole (Microtus ochrogaster) display populational differences in prosocial behavior and aggression based upon region-specific cultural upbringing and parental lineage. Prairie voles originating from Kansas (KS) display …

Long-Term Effects Of Adolescent Fluoxetine Exposure On Hippocampal Gene Expression In Male C57bl/6 Mice, Anapaula Themann

Open Access Theses & Dissertations

Mood-related disorders, including depression and anxiety, are prevalent among children and adolescents. This poses a public health challenge, given their adverse impact on these young populations. Treatment with the selective serotonin reuptake inhibitor fluoxetine (FLX) is the first line of pharmacological intervention in pediatric patients suffering from affect-related illnesses. Although the use of this antidepressant has been deemed efficacious in the juvenile population, the enduring neurobiological consequences of adolescent FLX exposure are not well understood. For this reason, we explored for persistent molecular adaptations, in the adult hippocampus, as a function of adolescent FLX pretreatment. To do this, we administered …

Chanism Of G-Βγ-Dependent Regulation Of Neuronal Differentiation And Neurodegeneration, Diana Olivas

Open Access Theses & Dissertations

Neurodegeneration is a pathological condition associated with a progressive loss of neurons, and occurs in many neurological disorders including Alzheimer’s disease (AD), Parkinson’s disease (PD) and Lou Gehrig’s disease (ALS). It is the most common cause of dementia among people 65 and older. With the increasing of life expectancy, the prevalence of neurodegenerative diseases is also increasing rapidly. However, the cause of this disorder is largely unknown, and no effective drugs are available to treat the disease process. Therefore, it is crucial to identify new target(s) and strategies for therapeutic interventions. Cytoskeletal defects followed by dysfunction is a major characteristic …

A Proposed Mechanism For Stimulant-Induced Behavioral Sensitization Involving The Transporter Vmat, Valeria Garcia

Open Access Theses & Dissertations

Elucidating mechanisms that drive drug craving is crucial to develop pharmacological interventions for addiction. Repeated exposure to psychostimulants produces an enhanced behavioral and neurochemical sensitivity to both the drug and drug-related cues, known as sensitization. We hypothesize that VMAT, the protein responsible for storage of dopamine (DA) into the vesicles, may be functionally altered to redistribute DA between the cytoplasmic pool and the vesicular pool based on demands for drug-mediated release versus neurotransmission in the context of conditioned environmental cues. To examine the role of VMAT, we pretreated rats with a VMAT blocker, tetrabenazine (TBZ), before each daily treatment of …

Effects Of Repeated Nicotine Vapor Exposure And Withdrawal On Somatic Signs, Anxiety-Like Behavior, And Brain Reward Thresholds In Male Sprague Dawley Rats, Michelle Martinez

Open Access Theses & Dissertations

No abstract provided.

Toward Automated Region Detection & Parcellation Of Rat Brain Tissue Images, Alexandro Arnal

Open Access Theses & Dissertations

People who analyze images of biological tissue often rely on segmentation of structures as a preliminary step. In particular, laboratories studying the rat brain manually delineate brain regions to position scientific findings on a brain atlas to propose hypotheses about the rat brain, and ultimately, the human brain. Our work intersects with the preliminary step of delineating regions in images of brain tissue via computational methods.

We investigate pixel-wise classification or segmentation of brain regions using ten histological images of brain tissue sections stained for Nissl substance, and two deep learning models: U-Net and Tile2Vec. Our goal is to assess …

Juvenile Fluoxetine Treatment Mediates An Anxiogenic Phenotype That Is Ameliorated By Its Re-Exposure In Adulthood, Francisco Javier Flores Ramirez

Open Access Theses & Dissertations

Accumulating preclinical evidence indicates that early-life exposure to psychotropic medications induce an anxiogenic-like behavioral profile in later life. However, these preclinical approaches have been conducted primarily using male subjects. This is problematic since clinical data indicates that women are more likely to be diagnosed with anxiety disorders than their male counterparts, and thus, women are prescribed with psychotropic medications like fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI), at significantly higher rates. Therefore, the goal of this Dissertation is to examine whether alterations in behavioral responses to anxiety-eliciting stimuli are exhibited in adulthood, as a result of early-life FLX exposure. …

Insulin Restores The Neurochemical Effects Of Nicotine In The Mesolimbic Pathway Of Diabetic Rats, Bryan Cruz

Open Access Theses & Dissertations

This study examined whether insulin modulates the neurochemical effects of nicotine in the mesolimbic pathway of diabetic rats. Rats received vehicle or streptozotocin (STZ) to induce hypoinsulinemia. A subset of STZ-treated rats was implanted with insulin pellets that rapidly normalized glucose levels. Two-weeks later, dialysis probes were implanted into the nucleus accumbens (NAc) and ipsilateral ventral tegmental area (VTA). The next day, dialysate samples were collected during baseline and then following systemic administration of nicotine. Samples were also collected following intra-VTA administration of the gamma-aminobutyric acid (GABA)A receptor antagonist, bicuculline. Dopamine, acetylcholine (ACh), GABA, and glutamate levels were assessed using …