Research Methods in Life Sciences Commons^™

Dissecting The Tissue-Specific Contributions To Seizures, Cardiorespiratory Dysfunction, And Sudden Death In The Kv1.1 Mouse Model Of Epilepsy Using Conditional Knockout Approaches, Kelsey Paulhus

Biological Sciences Theses and Dissertations

Sudden unexpected death in epilepsy (SUDEP), the primary cause of mortality in epilepsy, remains poorly understood. Studies suggest seizures may trigger dangerous signals affecting the heart and lungs leading to collapse and death. The Kv1.1 deficiency mouse model mirrors clinical SUDEP cases, showing spontaneous seizures, cardiorespiratory issues, and premature death. However, this model lacks regional specificity in Kv1.1 deletion, hindering insights into SUDEP’s mechanisms and anatomical substrates.

This dissertation employs three distinct conditional knockout (cKO) techniques to investigate the individual roles for the forebrain, brainstem, and heart in SUDEP related phenotypes. The findings reveal that the forebrain alone can trigger …

Puberty-Associated Changes In Kiss1r, Mc3r, And Mc4r In The Ewe, Ashleigh Caitlyn Thomson

Graduate Theses, Dissertations, and Problem Reports

The neural mechanisms that control the onset of puberty are not completely understood. In livestock, the onset of puberty relies on an increase in gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH). Kisspeptin, neurokinin B, and dynorphin neurons (KNDy) and their receptors, Kiss1r, NK3R, and KOR, respectively, are important regulators of puberty. Previous data from our laboratory has shown that KNDy neurons may be responding to other inputs, including the melanocortin system, that will affect the timing of puberty. Given this, we examined kisspeptin receptor (Kiss1r) mRNA expression in GnRH neurons as well as examining melanocortin 3 and 4 receptor …

Investigating The Age-Dependent Impact Of Lactate Dehydrogenase On Cognition In Flies And Mice, Ariel Khaya Frame

Electronic Thesis and Dissertation Repository

Lactate is a carbohydrate breakdown product typically produced in astrocytes, a type of glial cell, and transported to neurons within the brain. This type of metabolic coupling is commonly referred to as the astrocyte neuron lactate shuttle (ANLS). While numerous studies have shown that the ANLS is involved in cognition in mammals few have taken into consideration sex differences, changes with age, or evolutionary conservation in invertebrates. Lactate metabolism is controlled by the enzymatic interconversion of pyruvate and lactate in a reaction catalyzed by lactate dehydrogenase (LDH). In this thesis I examined cognitive changes across lifespan affected by genetic manipulation …

Epithelial Membrane Protein 3 (Emp3b) Is A Novel Regulator Of Sympathetic Nervous System Development In Zebrafish., Jessica M. White

Theses and Dissertations

Notable progress has been made in understanding the development of the neural crest (NC). Neural crest cells (NCCs) can be divided into 4-5 subpopulations. A major lineage among trunk NC derivatives are sympathoadrenal (SA) cells, which give rise to the sympathetic nervous system (SNS). Trunk NCCs follow a ventromedial migration pathway where signals derived from the dorsal aorta instruct migrating NCCs to a SA cell fate. Defects in NC development can result in syndromes known as neurocristopathies. Neuroblastoma is one of the most common forms of pediatric cancer affecting nearly 800 infants each year in the United States (Takita et …

The Impact Of Hiv-1 Tat And Morphine On Spatial Distribution Of Drugs In The Brain., Austin M. Jones

Theses and Dissertations

Despite combination antiretroviral therapy effectively suppressing HIV within the periphery, the central nervous system (CNS) remains affected by the virus. Approximately half of people living with HIV will experience HIV-associated neurocognitive disorders (HAND) or neuroHIV. Concurrent opioid use exacerbates neuroHIV by promoting neuroinflammation, viral replication, and potentially altering the antiretroviral concentrations within the brain.

Using a transgenic mouse that expresses the HIV-1 Tat protein, we examined the effects of Tat and morphine on antiretroviral accumulation and distribution and the effects of Tat on morphine accumulation within the brain using infrared matrix-assisted laser desorption electrospray ionization with mass spectrometry imaging (IR-MALDESI-MSI). …

Heat Shock Protein 90 (Hsp90) System In Health And Disease., Daniella Munezero

Graduate Theses, Dissertations, and Problem Reports

Cells rely on heat shock proteins (HSP) to facilitate and regulate the folding of the substrate proteins into their native state, and degradation if misfolding cannot be prevented. HSP90, a member of the HSP family, is a potential target for treatment of cancer and neurodegenerative diseases. Unfortunately, several clinical trials for cancer treatment have been discontinued due to cell toxicity accompanying HSP90 inhibition. HSP90 has four distinct but structurally similar paralogs. HSP90 inhibitors target all the paralogs despite increasing proof of functional differences among the paralogs. Understanding the in vivo function of HSP90 and the role played by each paralog …

Myeloarchitectonic Maps Of Cat Auditory Cortex, Austin Robertson

Electronic Thesis and Dissertation Repository

The cerebral cortex contains myriad cortical areas that differ in structure, function, and connectivity. Current methods of delineating cortical structures and their subregions are insufficient for in vivo applications, either being highly invasive or requiring a detailed knowledge of a region’s tuning properties. To address this, we seek to establish a structural biomarker capable of delineating the cortex that possesses a non-invasive correlate. We explore myelin as a potential candidate by evaluating its efficacy in parcellating the feline auditory cortex through the generation of depthwise myelin density profiles for each of the 13 auditory cortical subregions. Our analyses revealed significant …

Impacts On Fast-Start Performance: How Do Group Size And Habitat Degradation Alter The Escape Behavior Of A Schooling Coral Reef Fish?, Monica D. Bacchus

All HCAS Student Capstones, Theses, and Dissertations

Escaping predation is essential for species survival, but prey must effectively match their response to the perceived threat imposed by a predator. Fish evaluate their surroundings using several sensory stimuli, including olfactory, visual, auditory, and mechanical cues. A range of taxa use the fast-start response to evade predators, including fishes, sharks, and larval amphibians. While the fast-start response (rapid bursts of swimming) is extensively studied in solitary fishes, the factors that mediate the collective escape response in schools of fish have historically been investigated far less. To address this knowledge gap, the collective escape behavior and individual escape performance of …

Impact Of Brain State On Visual And Prefrontal Population Coding In Behaving Animals, Russell Milton

Dissertations & Theses (Open Access)

Patterns of neural activity in the brain constantly shift between different processing states. Earlier studies have established that the ongoing, spontaneous activity has major repercussions regarding how the brain processes incoming sensory stimuli. However, the interaction between behavioral activity and brain states throughout the cortical hierarchy of primates has not been understood. In particular, technical considerations have greatly limited the range of physical activities in which primate neuronal activity can be recorded. We have implemented two separate strategies to overcome these limitations. First, we have advanced wireless electrophysiological methodologies that enable recording high-yield neuronal data from animals as they freely …

The Effects Of D2 Receptor Modulation On Locomotor Development In Danio Rerio, Isaiah Thomas Mcroberts

Senior Projects Spring 2022

This study utilized a novel design to investigate the sensitivity of D2 dopamine receptors to modulating compounds through multiple exposures over early development of zebrafish larvae. Zebrafish were dosed for 30 minutes from 5-8 days post fertilization (dpf) with 16µ/mol of either a D2 antagonist, haloperidol, or a D2 agonist, quinpirole hydrochloride. Two other groups were then dosed with these compounds from 9-12dpf. The effects of D2 receptor modulation were measured by analyzing motor activity on measures of movement distance, frequency, and velocity. Results indicated that larvae dosed with haloperidol on 5dpf had increased activity after the first dosage, but …

Microfabrication And Electrochemical Characterization Of A Novel Su-8 Probe With An Array Of Individually Addressable Electrodes Suitable For Redox Cycling Experiments In Ultra-Small Volumes, Mahsa Lotfi Marchoubeh

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that utilizes closely spaced generator and collector electrodes to cycle reversible redox species between their oxidative states. With advantages in signal amplification, selectivity of species based on their electrochemical reaction mechanism, and limited or no background subtraction, this technique is well suited for selective detection of important electrochemically active molecules such as dopamine at basal or slowly changing levels.

Miniaturized medical devices have become an area of great interest for measurement of chemicals in limited volumes with low concentrations or in sensitive tissues. A probe on a polymeric SU-8 substrate with suitable dimensions and …

Evaluating Anesthetic Protocols For Non-Human Primate Functional Neuroimaging, Megha Verma

Electronic Thesis and Dissertation Repository

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that can be used to measure a proxy of neural activity in vivo with high spatial specificity. One subject can be followed for a long period of time to assess changes in functional brain organization. However, fMRI is extremely sensitive to motion. The challenges of training non-human primates to reduce motion in an MRI scanner motivate the study of anesthesia which is commonly used to substitute for this training. In this thesis, I compare three different commonly used anesthetic protocols: isoflurane, propofol-fentanyl in combination, and fentanyl alone, to test which of …

Mitochondrial Aspects Of Neuronal Pathology In Triple-Transgenic Alzheimer’S Disease Mice, John Zachary Cavendish

Graduate Theses, Dissertations, and Problem Reports

Alzheimer’s disease (AD) is a fatal, progressive neurodegenerative disease afflicting millions of people in the United States alone and is the only one of the top leading causes of morbidity and mortality with no effective disease-modifying therapies. It is the most common form of dementia, affecting one in three people over the age of 85. While the hallmarks of the disease include accumulation of beta-amyloid-based extracellular plaques and hyperphosphorylated tau-based intracellular neurofibrillary tangles, treatment strategies centered on removing or mitigating these components of AD have all failed in humans. Mitochondrial dysfunction has been increasingly recognized as an early and consistent …

Bypassing The Blood-Brain Barrier: A Physical And Pharmacological Approach For The Treatment Of Metastatic Brain Tumors, Samuel A. Sprowls

Graduate Theses, Dissertations, and Problem Reports

This dissertation (a) provided an in depth literature review of methods to disrupt the BBB/BTB and improve therapeutic distribution to brain tumors, (b) evaluated the use of azacitidine as a single agent therapy for the treatment of brain metastasis of breast cancer and a potential molecular mechanism by which brain tropic cells are sensitized to hypomethylating agents, (c) determined the impact cannabidiol has on P-glycoprotein mediated efflux at the blood-brain barrier and its potential for use as a single agent treatment for metastatic brain tumors, (d) developed a preclinical radiation therapy protocol for use in small animals and in vitro …

Translating Touches: New Approaches For Modeling And Rescuing Executive Function Deficits After Prenatal Alcohol Exposure, Johnny A. Kenton

Biomedical Sciences ETDs

Background: With a recent meta-analysis indicating that 9.8% of women worldwide consume alcohol during pregnancy, understanding the effects of fetal alcohol spectrum disorder (FASD) is critical for both identifying and treating those afflicted. Traditional preclinical research investigating the behavioral effects of neurodevelopmental disorders, such as FASD, has utilized tasks designed for specific animal models. For this reason, preclinical research into FASD requires a shift into clinically relevant behavioral testing. One such method involves touch-sensitive screens integrated into an operant box to emulate clinical computer-based tasks, such as the Cambridge Neuropsychological Test Automated Battery.

Methods: Here, we utilized a mouse model …

Effect Of Ambient Temperature On Recovery Of Surgically Instrumented Sprague-Dawley Rats, Gianna Mangone

Senior Honors Projects, 2020-current

Based on current guidelines for housing rodents after surgical instrumentation, rodents may be housed at temperatures that hinder surgical recovery and cause thermal stress– room temperature (21°C) being one of them. Rodents are often housed at room temperature since this temperature is easy for humans to be caring for them. However, if recovering rodents are thermally stressed, experimental results will be confounded. To address this issue, Sprague-Dawley rats were surgically instrumented with radiotelemtry thermoprobes (Data Sciences, #TA-10F40) to monitor their core temperatures, then housed at one of five temperatures to assess the effect ambient temperature had on multiple aspects of …

Sedative And Neurotoxic Properties Of Brexanolone Compared To Midazolam In The Developing Rodent Brain, Jacob Huffman

Dissertations

The developing brain is susceptible to extensive neurotoxicity following exposure to sedative/anesthetic drugs (SADs). Every year hundreds of thousands of children around the world are exposed to SADs with no viable non-neurotoxic agents approved for clinical use. Allopregnanolone (AlloP) has well-established sedative effects in adults and neonates. AlloP and many SADs produce sedation/anesthesia through allosteric modulation of GABA_A receptors, which is one of two principal mechanisms behind SAD-induced neurotoxicity. Evidence suggests AlloP has the unique capacity to regulate key apoptotic factors in adults and is widely involved with critical stages of neurodevelopment, indicating this neurosteroid might serve as a …

The Effect Of Hypoxia On Brain Cell Proliferation In Weakly Electric Fish, Petrocephalus Degeni, Kaitlin Klovdahl

Senior Theses and Projects

Oxygen levels tend to remain at a steady state concentration in the Earth’s atmosphere, yet in some bodies of water, they can fluctuate and decrease drastically. Many organisms that inhabit the swamps, lakes, streams, and parts of the ocean where this occurs have evolved adaptations to manage this environmental uncertainty and continue normal oxygen consumption. The Lwamunda swamp in Uganda is chronically hypoxic, yet it is home to many species, including the electric fish Petrocephalus degeni. P. degeni are unusual by nature of their immense brain, and the Lwamunda swamp appears ill-suited for maintaining this large, metabolically active organ. To …

Activation Of The Sonic Hedgehog Effector Smoothened Counteracts L-Dopa Induced Dyskinesia By Restoring Cholinergic Interneuron Function, Lauren Malave

Dissertations, Theses, and Capstone Projects

Many types of neurons act as multimodal signaling centers. Yet, we have only limited insight into the regulation and functional consequences of neuronal co-transmission. For example, dopamine (DA) neurons, whose degeneration causes motor deficits characteristic of Parkinson’s Diseases (PD), communicate with all their targets by DA but only a selective subset of their targets using GABA, Glutamate, and the secreted cell signaling protein Sonic Hedgehog (Shh). It is unknown whether Levo-dopamine (L-Dopa) induced dyskinesia (LIDs), a severely debilitating side effect of DA supplementation in PD, might appear because DA neuron targets are exposed to high DA- but low Shh- signaling …

A Neural Mechanism For Capnotaxis In The Naked Mole-Rat, Michael Zions

Dissertations, Theses, and Capstone Projects

A Neural Mechanism for Capnotaxis in the Naked Mole-Rat

The Naked Mole-Rat (NM-R) is a small hairless rodent that has thrived underground in the Horn of Africa for the past 40 million years. It was first discovered in 1847, but has only been maintained in captivity and studied as a laboratory animal over the past 40 years. To date, more than 400 scientific papers have been published on this species. This is relatively few compared to established lab animals like rats and mice, but those papers contain a trove of information that has changed our understanding of the constraints of …

Focal Augmentation Of Somatostatin Interneuron Function And Subsequent Circuit Effects In Developmentally Malformed, Epileptogenic Cortex, Nicole Ekanem

Theses and Dissertations

Drug-resistant epilepsy (DRE) is a common clinical sequela of developmental cortical malformations such as polymicrogyria. Unfortunately, much remains unknown about the aberrant GABA-mediated circuit alterations that underlie DRE's onset and persistence in this context. To address this knowledge gap, we utilized the transcranial freeze lesion model in optogenetic mice lines (Somatostatin (SST)-Cre or Parvalbumin (PV)-Cre x floxed channelrhodopsin-2) to dissect features of the SST, PV, and pyramidal neuron microcircuit that are potentially associated with DRE. Investigations took place within developmental microgyria’s known pathological substrate, the adjoined and epileptogenic paramicrogyral region (PMR). As well, microcircuit relationships within the previously unexplored range …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Characterizing The Requirements For The Matricellular Protein, Dccn, In Nervous System Function, Elizabeth L. Catudio Garrett

Graduate Student Theses, Dissertations, & Professional Papers

The brain is organized as a complex network of specialized neurons that communicate via a combination of electrical and chemical signals. Our brains function to generate movement, control organ function, or direct complex behaviors; all of which requires the ability to regulate the flow of communication between circuits and networks. Work in this thesis addresses two areas of neuron communication: first, how does the release of more than one neurotransmitter from a single neuron impact behavior, and second, are matricellular proteins (MCPs) key contributors to synaptic transmission and neuron function? The conserved CCN family of MCPs have a …

In Search Of Psychiatric Kinds: Natural Kinds And Natural Classification In Psychiatry, Nicholas Slothouber

Electronic Thesis and Dissertation Repository

In recent years both philosophers and scientists have asked whether or not our current kinds of mental disorder—e.g., schizophrenia, depression, bipolar disorder—are natural kinds; and, moreover, whether or not the search for natural kinds of mental disorder is a realistic desideratum for psychiatry. In this dissertation I clarify the sense in which a kind can be said to be “natural” or “real” and argue that, despite a few notable exceptions, kinds of mental disorder cannot be considered natural kinds. Furthermore, I contend that psychopathological phenomena do not cluster together into kinds in the way that paradigmatic natural kinds (e.g., chemical …

Towards A Better Understanding Of Temporomandibular Disorder, Jessica R. Cox

MSU Graduate Theses

Results from the OPPERA study provided evidence that risk factors such as neck muscle tension, prolonged jaw opening, and female gender increase the likelihood of developing temporomandibular joint disorders (TMJD), which are prevalent, debilitating orofacial pain conditions. Peripheral and central sensitization, which mediate a lowering of the stimulus required for pain signaling, are implicated in the underlying pathology of chronic TMJD. The goal of my study was to investigate cellular changes in the expression of proteins associated with the development of central sensitization. Female Sprague-Dawley rats were injected with complete Freund’s adjuvant in the upper trapezius muscles to promote trigeminal …

Molecular Targets Of Psychedelics And Their Role In Behavioral Models Of Hallucinogenic Action, Hiba Z. Vohra

Theses and Dissertations

Psychedelics are a subset of hallucinogenic drugs that exert their characteristic effects through agonist activity at the serotonin receptor 2A (5-HT_2A). In this study, I aimed to characterize the modulatory role of the metabotropic glutamate subtype 2 receptor (mGluR2) in the 5-HT_2A-specific rodent model of hallucinogenic action, head-twitch response (HTR). Secondly, I aimed to explore if 5-HT_2A agonist-induced deficits in prepulse inhibition (PPI) of the startle response, an additional model of hallucinogenic action, could be produced in mice. Though 5-HT_2A agonist-induced PPI deficits, which represent interruptions in normal sensorimotor gating, have been described in …

Cannabinoid Transmission In The Basolateral Amygdala Modulates Prefrontal Cortex And Ventral Hippocampal Activity, Brian J. Pereira

Electronic Thesis and Dissertation Repository

The cannabinoid system is important for maintaining neuron-to-neuron communication within the mammalian brain. One of the most commonly used substances to alter the cannabinoid system is cannabis. Individuals who are exposed to cannabis report having dissociable effects; both positive and negative. High amounts of THC have been commonly associated with the negative effects of cannabis, whereas CBD can be used to counter these. Pre-clinical evidence suggests that the combination of the two compounds can produce a therapeutic benefit for individuals who are susceptible to the effects of THC. The present study investigates whether the combination of THC+CBD can prevent electrophysiological …

Possible Breakdown Of Dopamine Receptor Synergism In A Mouse Model Of Huntington's Disease, Samantha F. Kennedy

University of New Orleans Theses and Dissertations

The model of basal ganglia function proposed by Albin, Young and Penney (1989) describes two anatomically independent motor pathways, the direct and indirect. However, under normal conditions striatal dopamine (DA) is required for the expression of motor behavior, and DAergic control of the two pathways (via D1 and D2 receptors, respectively) is dependent on co-activation. We tested for a possible breakdown of D1/D2 synergism using transgenic R6/1 mice bearing the human huntingtin allele (Htt). Motor stereotypy, observed prior to the onset of HD-related symptoms, was rated on a 5-point scale following activation of: A) D1 receptors alone, B) D2 receptors …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

Effects Of Food Consumption On Cell Proliferation In The Brain Of Python Regius, Stacy Star Habroun

Master's Theses

Neurogenesis is an important and vastly under-explored area in reptiles. While the ability to generate new brain cells in the adult mammalian brain is limited, reptiles are able to regenerate large populations of neuronal cells. Pythons exhibit a characteristic specific dynamic action (SDA) response after food intake with an increase in metabolic rate that facilitates processing the meal. Associated with this change in SDA, pythons (Python spp.) also exhibit impressive plasticity in their digestive and cardiovascular physiology due to the sheer magnitude of the increase in organ growth that occurs after a meal to speed digestion, absorption, and assimilation of …