Life Sciences Commons^™

Neural Responses To Magnetic Orientation Information In Songbirds, Madeleine Ir Brodbeck

Electronic Thesis and Dissertation Repository

Effective navigation and orientation is essential for animals to survive. The study of migratory birds provides insights into these processes, particularly through mechanisms like the geomagnetic compass, which uses Earth's magnetic field for directional information. A brain region in songbirds relevant to this is cluster N, known for its potential role in processing geomagnetic information. Notably, cluster N appears exclusive to nocturnally migratory birds, being active solely at night, and lesion studies reveal that an intact cluster N is necessary for geomagnetic compass orientation. However, given the scarcity of empirical data concerning cluster N, substantial questions persist regarding its function. …

The Modulation Of Lfp Characteristics In The Freely Moving Common Marmoset, William Jm Assis

Electronic Thesis and Dissertation Repository

The hippocampus is a neural structure critical for navigation. Neurons in this region, along with others, create a functional network which generates large-amplitude modulations known as local field potential (LFP) activity. Prior LFP research has predominantly used rodent animal models, however recent studies have shown that frequencies associated with navigation in other mammals do not correlate to those of the rodent. We hypothesized that LFP characteristics in the common marmoset are modulated by the speed and axis of travel of the animal. Two marmosets were placed in a free moving 3-dimensional environment where movement and neurological activity were recorded. Results …

Morphological Characterization Of Two Transgenic Strategies For Genetic Access To Semilunar Granule Neurons In The Mouse Dentate Gyrus, David T. Rexford

Masters Theses

Granule cells (GCs) of the dentate gyrus (DG) have been understood as a homogeneous class of neurons exhibiting a characteristic limited firing pattern. A subtype of GC called a semilunar granule cell (SGC) has been identified exhibiting variant morphology, electrophysiology, and positioning from normal GCs. SGCs represent an emerging novel subpopulation of GCs, however, there is presently no genetic tool to access SGCs separately from normal GCs. To provide access for future in vivo studies of this population, we examined two genetic strategies for putative SGC specificity in mouse brain slices. Morphological analysis was performed for quantitative identification of putative …

Characterizing The Roles Of The Variable Linker And Hub Domains In Camkii Activation, Noelle Dziedzic

Doctoral Dissertations

Learning and memory formation at the cellular level involves decoding complex electrochemical signals between nerve cells, or neurons. Understanding these processes at the molecular level requires a comprehensive study of calcium-sensitive proteins that serve as signal mediators within cells. More specifically, the protein calcium/calmodulin-dependent protein kinase II (CaMKII) is a key regulator of downstream cellular signaling events in the brain, playing an important role in long term memory formation. CaMKII is encoded in humans on four different genes: alpha, beta, gamma and delta. For added complexity, each of these gene products can be alternatively spliced and translated into multiple protein …

Artificial Light At Night Disrupts Pain Behavior And Cerebrovascular Structure In Mice, Jacob Raymond Bumgarner

Graduate Theses, Dissertations, and Problem Reports

Artificial Light at Night Disrupts Pain Behavior and Cerebrovascular Structure in Mice

Jacob R. Bumgarner

Circadian rhythms are intrinsic biological processes that fluctuate in function with a period of approximately 24 hours. These rhythms are precisely synchronized to the 24- hour day of the Earth by external rhythmic signaling cues. Solar light-dark cycles are the most potent environmental signaling cue for terrestrial organisms to align internal rhythms with the external day. Proper alignment and synchrony of internal circadian rhythms with external environmental rhythms are essential for health and optimal biological function.

The modern human environment on Earth is no longer …

Context, Goals, And Operant Behavior: The Role Of The Prelimbic Cortex And Associated Neural Circuitry, Callum Mark Piper Thomas

Graduate College Dissertations and Theses

Operant (instrumental) conditioning is a laboratory model of voluntary behavior. In its simplest form, performing a particular response, such as a lever press, leads to delivery of a reinforcing outcome (e.g., a sucrose pellet). Operant behaviors can be associated with preceding stimuli (“habits”) or outcomes (“goal-directed actions”). A factor that influences performance of operant behaviors is the context in which they are learned. Contexts can be defined as background stimuli that are present during behavior. For example, eating dessert may occur in the context of a restaurant and the sated feeling of a finished meal. The context for eating dessert, …

Hyperparameter Codependence In Fieldnet: Guidelines For Ann Construction, Seiji Akera

Pitzer Senior Theses

Artificial Neural Networks (ANNs) comprise a non-linear modeling method that is often used to analyze neural data in place of linear models. These networks fall under one of two classifications: pure prediction purposes and improving understanding of the brain through neural interpretability. FieldNet is an ANN designed by Dr. Gautam Agarwal that takes complex valued theta oscillations recorded from implanted multi-electrodes and predicts the rat’s location as it moves throughout a maze. In learning neural features to make this classification, FieldNet appears to reconstruct place fields. The construction of FieldNet has an impact on both the performance and reconstruction capabilities …

Deciphering The Firing Patterns Of Hippocampal Neurons During Sharp-Wave Ripples, Kourosh Maboudi Ashmankamachali

Theses and Dissertations

The hippocampus is essential for learning and memory. Neurons in the rat hippocampus selectively fire when the animal is at specific locations - place fields - within an environment. Place fields corresponding to such place cells tile the entire environment, forming a stable spatial map supporting navigation and planning. Remarkably, the same place cells reactivate together outside of their place fields and in coincidence with sharp-wave ripples (SWRs) - dominant electrical field oscillations (150-250 Hz) in the hippocampus. These offline SWR events frequently occur during quiet wake periods in the middle of exploration and the follow-up slow-wave sleep and are …

Spatial Representation In Postrhinal Cortex, Patrick Lachance

Dartmouth College Ph.D Dissertations

Animals rely on a variety of internal and external cues to orient themselves when navigating their environments and determining their current spatial context. Information regarding these cues enters the brain from the navigator’s first-person perspective. Information of this type is considered to be egocentric, or self-centered. However, decades of behavioral, electrophysiological, and imaging research suggest that the brain contains a rich collection of spatial representations that are unrestricted by the animal’s first-person perspective, and instead are defined relative to the surrounding environment. These representations are considered allocentric, or world-centered. Despite an abundance of promising modeling work, the specific mechanisms by …

Mirnas Levels In A Streptozocin Model Of Alzheimer’S Disease, Nada Moustafa

Theses and Dissertations

Dementia entails a progressive decrease in cognitive functions, with 50%-75% of cases attributed to Alzheimer’s disease (AD); an aging-associated condition characterized by the build-up of tangled phosphorylated Tau (p-Tau) protein and beta-amyloid (Aβ) depositions. Sporadic AD (sAD) is multifactorial in nature, resulting from a combination of environmental and genetic predisposing factors. Type 2 diabetes mellitus (T2DM) is a leading risk factor for dementia, and deregulation of brain glucose metabolism is associated with early cognitive affection in sAD. Thus, the diabetogenic agent Streptozotocin (STZ) is used to experimentally create an AD model in animals (STZ-induced sAD), in which abnormalities in cerebral …

Examining Limbic Sexual Dimorphisms In Schizophrenia, Kennedy S. Madrid

Undergraduate Honors Theses

Schizophrenia is a mental disorder that affects a significant number of individuals in the United States and can have numerous different symptoms. Recently, interest in the differences between the neuroanatomy of individuals with schizophrenia and individuals without schizophrenia has emerged, specifically the sexual dimorphism in individuals with schizophrenia. This study aimed to gain a better understanding of the sexual dimorphisms of two structures in the limbic system: the hippocampus and amygdala. Data was harmonized and analyzed from two datasets to determine the sexual dimorphic factor of these structures in healthy controls and individuals with schizophrenia. Demographic features were also taken …

Withdrawal From Voluntary Oral Methamphetamine Reveals Female Specific Susceptibilities To Behavioral Deficits And Neurochemical Perpetuators Of Neurotoxicity And Drug Seeking Behavior, Nicoletta K. Memos

Dissertations, Theses, and Capstone Projects

MA is a potent, highly addictive psychomotor stimulant known to produce neurotoxic effects on the brain leading to neurological impairments^1-6 characterized by neurodegeneration of dopaminergic fibers, cell bodies and pathways, as well as brain regions such as the hippocampus, frontal cortex, and midbrain^1,5.

In MA addiction, women are more vulnerable to the behavioral and cognitive effects of MA compared to men. Adult human literature reveals gender differences in usage patterns and women demonstrate increased vulnerability to the neurotoxic effects and health effects of MA use. Women begin drug use at an earlier age, escalate drug use quicker, …

The Effects Of Astrocytic Derived Insulin-Like Growth Factor (Igf-1) On Cognition And Astrocytes, Destiny Wilson

Honors Theses

Insulin-like growth factor 1 (IGF-1) is a neuroendocrine signaling hormone that plays a vital role in growth and development, as well as learning and memory. Inhibition of this hormone results in cognitive impairments like those seen with age-related decline. While a majority of research has focused on the role of IGF-1 on neurons, the role of astrocytes still needs to be explored. Our research investigates how astrocytes and cognition are affected as a result of direct regulation of localized IGF-1 production in early development and after puberty. Preliminary studies in our laboratory established a connection between IGF-1 and glial fibrillary …

Investigating Mechanisms Of Injury And Intervention In A Novel In Vitro Model Of Traumatic Brain Injury In Organotypic Hippocampal Slice Cultures, Julia Elaine Jagielo-Miller

Theses and Dissertations--Psychology

Traumatic brain injuries (TBIs) impact millions of individuals each year and can pose long term consequences. Despite numerous attempts, no medication has been approved by the FDA to treat TBIs. The causes of these failed trials are multifaceted, but in part can be attributed to the complex nature of TBIs, as well as a lack of sufficient pre-clinical data. In vitro models of TBI are an important tool to help understand the cellular changes seen following the injury, in a highly controlled environment. For the following experiments, a novel model of TBI was used to injure organotypic hippocampal slice cultures, …

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 …

Effects Of A Novel, Non-Toxic Histone Deacetylase Inhibitor On Hippocampal Memory Formation, Histone Acetylation, And Bdnf Gene Expression In Male Mice, Sarah Brianna Beamish

Theses and Dissertations

Memory dysfunction is a common symptom of aging, neuropsychiatric disorders, and neurodegenerative disorders, yet truly effective treatments for memory loss do not exist. De novo gene transcription is a molecular requirement for long-term memory formation. The transcription of genes related to synaptic plasticity and learning are regulated in part by histone acetylation, an epigenetic mechanism that regulates chromatin accessibility. Pharmacological compounds that maintain histone acetylation, called histone deacetylase inhibitors (HDACi), enhance memory by preventing deacetylation of core histone proteins, which initiates binding of transcriptional machinery to open chromatin. Therefore, HDACi are potentially promising therapeutics that could be used to prevent …

Targeting Ampa Receptor Modulation During Early Life Adversity: A Mediator For Threat Associated Memories, Roseanna M. Zanca

Dissertations, Theses, and Capstone Projects

Early life adversity (ELA) is the exposure to a single or to multiple traumatic events before the age of 18 that go beyond the child’s coping. These adverse events are often exacerbated during adolescence particularly when cognitive performance is compromised. Adolescents who experienced ELA may show symptoms of post-traumatic stress disorder (PTSD), while not vividly recalling the early life trauma. These individuals show atypical connectivity between prefrontal-amygdala and hippocampus, all of which is associated with an increased risk of experiencing a traumatic event again later in life. While clinical research has increasingly stressed the importance in addressing the long-lasting consequences …

Sex Differences In The Role Of Cornichon Homolog-3 On Spatial Memory And Synaptic Plasticity, Hannah Elizabeth Frye

Arts & Sciences Electronic Theses and Dissertations

Cornichon homolog-3 (CNIH3) is an AMPA receptor (AMPAR) auxiliary protein highly expressed in the dorsal hippocampus (dHPC), a region where AMPARs are critical for spatial memory and synaptic plasticity. A 2016 genome-wide association study (GWAS) by Nelson et al. identified single nucleotide polymorphisms (SNPs) in the gene CNIH3 to be associated with reduced individual risk for the development of opioid use disorder (OUD) in individuals with prior opioid exposure. We previously demonstrated a key role for AMPARs in the dHPC in opioid-associated learning and memory, therefore we hypothesized that CNIH3 in the dHPC may mediate learning and memory processes through …

Dedicated Interneuronal Microcircuits Regulated By Behavioral State, Moises William Arriaga

Arts & Sciences Electronic Theses and Dissertations

The hippocampus is a critical brain structure for learning and memory. Neuronal inhibition within the hippocampus, performed by a wide variety of inhibitory interneuron subtypes, is required to organize and regulate the cell activity and circuit operations which underly memory formation. Despite the importance of inhibitory interneurons to the function of the hippocampus, detailed descriptions of the role of interneurons in the regulation of network activity have been limited by difficulties associated with identifying and recording from these cells using traditional electrophysiology techniques, especially in awake, behaving animals. To better investigate the function of hippocampal interneurons in awake, behaving animals, …

The Effects Of Interneuron Progenitor Cell Transplantation On Network Dynamics In An Animal Model Of Mesial Temporal Lobe Epilepsy, Willie Curry

Graduate College Dissertations and Theses

Epilepsy is associated with a very high incidence of cognitive and behavioral comorbidities that are detrimental to overall quality of life. Current treatments for epilepsy,namely anticonvulsant pharmacological agents, generally increase the amount of inhibitory drive in order to counteract the hyperexcitability observed in the disorder. However, administration of these agents, while effective for 70% of epilepsy sufferers, leave a residual 30% of patients who don’t become seizure-free. The concomitant adverse side effects of anticonvulsants - these can paradoxically include increased cognitive "fog" or confusion, automatisms, and even increased number of seizures - are a great additional concern, as is the …

Behavioral, Endocrine, And Neural Responses To Stress In Postpartum And Nulliparous Rats : Potential Mechanisms Of Postpartum Stress Resilience, Joanna Medina

Legacy Theses & Dissertations (2009 - 2024)

Major depressive disorder is one of the most pervasive psychiatric illnesses in the United States. Women are at greater risk for developing depression, particularly during their childbearing years. Approximately 17% of new mothers develop postpartum depression within 4 weeks after parturition. The risk for postpartum depression is even greater in women who do not breastfeed or stop breastfeeding early. Major depressive disorder and postpartum depression share the same symptomology and common etiological bases. Dysregulated stress responses, dopamine activity, and neuroinflammation are recognized mechanisms for depression. The transition to motherhood encompasses physiological and behavioral adaptations in the brain essential for ensuring …

The Role Of The Circadian Clock Protein Rev-Erba In Neuroinflammation & Synaptic Health, Percy Griffin

Arts & Sciences Electronic Theses and Dissertations

Circadian rhythms are cycles of physiological activity that are conserved across all of life’s taxa – ranging from cyanobacteria to humans - due to their importance. They are conserved to allow organisms to maximize their capacity to obtain resources in their environment. In mammals, light and dark input into the retina is the strongest synchronizer of circadian rhythms. On the molecular level, this tightly regulated transcriptional-translational feedback loop is orchestrated by proteins with cyclical expression. The loss of these proteins has functional consequences on human health and diseases.

Recently, associations have been made between circadian proteins and a host of …

The Association Of Aerobic Fitness With Resting State Functional Connectivity And Verbal Learning And Memory In Healthy Young Adults, Kyle Joseph Jennette

Theses and Dissertations

The beneficial effects of exercise and cardiopulmonary fitness on general health, quality of life, and reduction of mortality are well known in older adults. There is evidence to support the positive effects of exercise and aerobic fitness on psychiatric and neurocognitive function in children, adults, and older adults. Indeed, many studies have explored the positive effects of aerobic fitness on slowing cognitive decline associated with normal and pathological aging. However, comparatively fewer empirical studies in the literature exist to support and understand the effects of aerobic fitness on the developing brain, particularly during adolescence and young adulthood, especially as it …

Shaped By The Environment: The Influence Of Childhood Trauma Exposure, Individual Socioeconomic Position, And Neighborhood Disadvantage On Brain Morphology, Elisabeth Kathleen Webb

Theses and Dissertations

The relationship between an individual’s socioeconomic position (SEP) and their overall physical and mental health has been well demonstrated. Far less is known about how area-level factors, such as neighborhood disadvantage, “get under the skin”. Previous research indicates lower SEP and childhood trauma negatively effects brain structure and function. The hippocampus, amygdala, and ventromedial prefrontal cortex (vmPFC) are particularly vulnerable to adversity. The current study investigated how individual SEP, childhood trauma, and neighborhood disadvantage impact these structures. Two-hundred and fifteen individuals were recruited from an Emergency Department in southeastern Wisconsin. Two-weeks post-traumatic injury, participants completed a structural magnetic resonance imaging …

Optogenetic Interrogation Of Hippocampal Circuit Stabilization, Laurel Watkins De Jong

Theses and Dissertations

Understanding the response of excitatory and inhibitory populations to varying input is vital to understanding how a brain region transforms information. Optogenetics - the combined use of optics and genetics to control the activity of proteins, provides neuroscientists with a tool to interrogate neuronal circuits with high spatio-temporal resolution and targeted cell specificity. This thesis examines the effects of optogenetic manipulations on hippocampal circuit responses. The hippocampus is a structure required for the formation and retention of episodic memories and is comprised of anatomically distinct subregions including cornu ammonis 3 (CA3) and cornu ammonis 1 (CA1). Both regions, despite differences …

Expression Analyses Of Hippocampal And Cortical Proteins In A Rat Model For Alzheimer’S Disease, Rangon Islam

Theses and Dissertations

Currently, Alzheimer’s disease (AD) has no cure. Using a rat AD model, we identified aberrantly expressed proteins during pre-pathology as potential biomarkers. The expression of certain biomarkers was reversed by diazoxide, a repurposed hypertension drug. These results suggest that drug repurposing at an early stage of AD has therapeutic potential.

Sexually Dimorphic Alterations In Brain Morphology Of Astrocyte Conditional System Xc- Knockout Mice, Gabrielle Emily Samulewicz

Honors Capstone Projects - All

Astrocytes play a vital role in orchestrating the precise brain wiring that occurs during development and are essential for maintaining homeostasis into adulthood. The cystine/glutamate antiporter, system xc-, in the central nervous system is especially abundant in astrocytes and itself is known to contribute importantly to the basal extracellular glutamate concentration as well as the intracellular and extracellular glutathione levels, either of which, if perturbed, could alter brain development and/or contribute to degeneration. Thus, to determine whether loss of astrocyte system xc- might alter brain morphology, I studied a conditional astrocyte system xc- knockout mouse (AcKO). Tissue was harvested from …

Levels Of Parp1-Immunoreactivity In The Human Brain In Major Depressive Disorder, Aamir Shaikh

Undergraduate Honors Theses

MDD is a severe and debilitating disorder that is associated with a growing global economic burden due to reduced workplace productivity along with increased healthcare resource utilization. Furthermore, depression markedly enhances the risk for suicide, mortality that is especially worrisome given that 30% of depressed individuals have an inadequate response to current antidepressants. This inadequacy of antidepressants necessitates the discovery of a better understanding of the pathobiology of MDD. Most current antidepressants work through monoamine neurotransmitters, and their relative efficacy in depression led to the now dated monoamine-deficiency hypothesis. The limited usefulness of antidepressants has led to a reinvigorated search …

Divergence In Neuronal Calcium Dysregulation In Brain Aging And Animal Models Of Ad, Adam Ghoweri

Theses and Dissertations--Pharmacology and Nutritional Sciences

Neuronal calcium dysregulation first garnered attention during the mid-1980’s as a key factor in brain aging, which led to the formulation of the Ca²⁺ hypothesis of brain aging and dementia. Indeed, many Ca²⁺-dependent cellular processes that change with age, including an increase in the afterhyperpolarization, a decrease in long-term potentiation, an increased susceptibility to long-term depression, and a reduction in short-term synaptic plasticity, have been identified. It was later determined that increased intracellular Ca²⁺ with age was due to increased Ca²⁺ channel density, elevated release from intracellular Ca²⁺ stores, and decreased Ca²⁺ buffering …

The Dysregulation Of Circadian Rhythms And Its Relation To Hippocampal Neurodegenerative Disease, John Patrick Mccauley

Legacy Theses & Dissertations (2009 - 2024)

Circadian rhythms modulate body temperature, sleep-wake cycles and cognitive functions like learning and memory. Interestingly, patients suffering from neurodegenerative disease like Alzheimer’s disease and brain insults like traumatic brain injury experience dysregulated circadian rhythms and learning and memory deficiencies as a symptom. The core molecular machinery that establishes these rhythms relies on the activation of positive and negative transcriptional-translational feedback loops within the hypothalamic suprachiasmatic nucleus (SCN). Subordinate circadian oscillators distributed throughout the peripheral and central nervous system follow the rhythmic activity of the SCN. One of these, the hippocampus, is mostly involved in regulating memory formation and recall. Experimental …