Medical Neurobiology Commons^™

Taste And Learning In The Gustatory Cortex, Martin Raymond

Alternative Theses and Dissertations (AETDs)

This research investigates the organization of taste representations in the gustatory cortex (GC) through two experiments utilizing miniscope imaging in mice. The first experiment focuses on conditioned taste aversion (CTA) and reveals that taste representations in GC are heavily dominated by palatability, with shifts in representational space occurring as a function of learning and extinction. The second experiment explores the interrelation of aversive stimuli, the impact of novelty on taste representations, and the role of somatosensory feedback. Findings suggest that familiarity and palatability emerge as positive signals with experience, shaping taste representations in GC. The study contributes to a nuanced …

The Interaction Between Host G3bp And Viral Nucleocapsid Protein Regulates Sars-Cov-2 Replication, Zemin Yang

Theses and Dissertations (ETD)

G3BP1/2 are RNA-binding proteins that promote condensation to form stress granules in response to various cellular stresses, including viral infection. G3BP1/2 are prominent interactors of the nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the functional consequences of the G3BP-N interaction in the context of viral infection have remained unclear. Here we used structural and biochemical analyses to define the residues required for G3BP1-N interaction, followed by structure-guided mutagenesis of G3BP1 and N to selectively disrupt their interaction. We found that mutation of N-F17 led to selective loss of interaction with G3BP1 and consequent failure of …

The Effects Of Exosomal Derived Tsg-6 On Microglia Activation, Jonathan A. Martinez, Rajashekhar Gangaraju Md

Longitudinal Scholar's Project

Following a traumatic brain injury, microglia become overactive for long periods and display pathologic behavior. We have shown that concentrated conditioned media from adipose tissue-derived mesenchymal stem cells (MSC-CCM) can suppress microglial activation. In this pilot study, we evaluated the efficacy of exosomes containing TNF-stimulated gene 6 (TSG6) derived from MSC-CCM on decreasing microglial activation in vitro via phagocytic activity and pro-inflammatory microglial gene expression.

Cerebellar Coordination Of Neuronal And Behavioral Rhythms, Brittany Correia Chapman

Theses and Dissertations (ETD)

Long known for its role in motor control, it is increasingly clear that the cerebellum is also involved in numerous cognitive and affective behaviors. Though the neuronal mechanism for the role of the cerebellum in cognition is still unclear, there is a consensus that it involves cerebellar interactions with the cerebral cortex. Recent studies suggest that the cerebellum monitors, and possibly coordinates, the precise phase alignment or coherence of neuronal oscillations in cerebral cortical areas. Here, we asked how loss of cerebellar function affects respiratory rhythms and the interactions of local field potential (LFP) oscillations between the lobulus simplex (LS) …

A Neurophysiological Investigation Of Listening Effort In Normal Hearing Adults Using Fnirs And Pupillometry, Jessica Defenderfer

Theses and Dissertations (ETD)

Real-world conversations are often accompanied by some sort of interference that challenges the clarity of the speaker’s message, causing listeners to exert more effort to understand speech. Previous research has demonstrated that when listening to speech becomes difficult, various regions of the brain are recruited beyond those which engage during optimal listening conditions. However, the neural correlates that underly listening effort are not fully understood. Importantly, the pupillary response can be used to index listening effort, such that pupil size increases with increasing cognitive demand. I proposed that pupillometry can be used to characterize the cortical response, such that changes …

Effects Of Genetics And Sex On Hippocampal Gene Expression And Adolescent Behaviors Following Neonatal Ethanol Exposure In Bxd Recombinant Inbred Mice, Jessica A. Baker

Theses and Dissertations (ETD)

Fetal alcohol spectrum disorders (FASD) are the leading preventable neurodevelopmental disorders in the western world. A hallmark symptom of FASD is cognitive and learning deficits that present in early childhood and continue throughout adulthood. Teratogenic effects of alcohol include increased cell death in the hippocampus, a brain region critically important in learning and memory. Genetics have been shown to have a role in the severity of alcohol’s teratogenic effect on the developing brain. Previous work in our lab identified differential vulnerability to ethanol-induced call death in the hippocampus using fourteen BXD strains and the two parental strains. The goal of …

Taste Learning In Insular Cortex: Plasticity Is Influenced By Experience Type, Stephanie Marie Staszko

Theses and Dissertations (ETD)

The gustatory cortex (GC) has long been studied as the main cortical area encoding taste stimuli and likely integrates sensory, visceral, and emotional information to guide taste-related behaviors. However, our understanding of cortical taste coding on a single-cell level has only become clear in recent years. The anatomical location of GC on the lateral and ventral surface of the brain makes it difficult to target with traditional imaging methods. Thus, much of what we know about cortical taste coding and cortical taste plasticity has been derived either from multiunit electrode recordings or anesthetized imaging experiments, techniques which lack the ability …

Role Of Cerebral Vasculature And Effect Of Circulating Exosomes In Propagation Of Systemic Inflammatory Responses Into The Central Nervous System, Mahesh Chandra Kodali

Theses and Dissertations (ETD)

Sepsis-associated encephalopathy (SAE) is an acutely progressing brain dysfunction induced by systemic inflammation. The mechanism of initiation of neuroinflammation during SAE, which ultimately leads to delirium and cognitive dysfunction, remains elusive. The goal of this project was to study the molecular events of SAE to capture its onset and progression into the central nervous system (CNS), and further identify the cellular players involved in mediating acute inflammatory signaling. Gene expression profiling on the cerebral vessels isolated from the brains of the mice treated with peripheral lipopolysaccharide (LPS) revealed that the cerebral vasculature responds within minutes to acute systemic inflammation by …

Conditional Loss Of Engrailed 1/2 In Rhombic Lip-Derived Neurons Increases Intrinsic Rhythmicity And Decreases Overall Variability Of Eupneic Respiration, Angela P. Taylor

Theses and Dissertations (ETD)

Evidence for a cerebellar role during cardiopulmonary challenges has long been established, but investigation into cerebellar involvement in eupneic breathing has been inconclusive. Given the view of the cerebellum (CRB) as a temporally coordinating structure, any investigation into the CRB during respiration must evaluate rhythm and variability of the respiratory sequence. In this study, we chose an elegant model of cerebellar neuropathology, Atoh1-En1/2 CKO, where mutant animals have conditional loss of the developmental patterning gene Engrailed 1/2 in rhombic lip-lineage neurons and exhibit a proportional scaling-down of neuron number in hypoplastic lobules of the CRB. We utilized whole-body unrestrained plethysmography …

Pathogenicity And Protection Mediated By A Single Tcrβ In Experimental Autoimmune Encephalomyelitis, Tianhua Wu

Theses and Dissertations (ETD)

How the TCR repertoire, together with risk-associated major histocompatibility complex (MHC), imposes susceptibility for autoimmune disease is not fully understood. A small fraction of TCR α or β chains are “public”, and are shared by most individuals.High-throughput sequencing of the mouse TCRβ repertoire during myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmuneencephalomyelitis (EAE) identified a public TCRβ chain, TCRβ1, which was highly shared among individual mice and preferentially deployed during EAE. Retrogenic expression of TCRβ1 resulted in spontaneous early-onset EAE in mice with high penetrance and severity, despite being paired with a diverse endogenous TCRα repertoire. To further study autoimmunity conferred by …

Pitx3null Mutant (Striatal Dopamine-Deficient) Mice Have Exaggerated Spiny Projection Neuron Responses To L-Dopa And D1 Agonism And Lack Baseline Striatonigral Spiking, Ben Sagot

Theses and Dissertations (ETD)

L-3,4 dihidroxyphenylalanine (l-DOPA) strongly stimulates motor activity in parkinsonian patients and animal models of Parkinson's disease. Severe striatal dopamine (DA) loss characterizes Parkinson's disease and its animal models. Given the canonical rate model of Parkinson's Disease pathophysiology based on differences in DA pharmacology manifesting as electrophysiological differences in striatal projection neuron (SPN) spike rates, SPNs should increase spiking during the motor response to l-DOPA. In fact, stimulating specific subsets of these neurons to spike in freely-moving wild type and parkinsonian animals causes or inhibits motor activity as predicted. However, pharmacological effects of DA deficiency, let alone those of DA replacement, …

Assessing Neuronal Synchrony And Brain Function Through Local Field Potential And Spike Analysis, Samuel Stuart Mcafee

Theses and Dissertations (ETD)

Studies of neuronal network oscillations and rhythmic neuronal synchronization have led to a number of important insights in recent years, giving us a better understanding of the temporal organization of neuronal activity related to essential brain functions like sensory processing and cognition. Important principles and theories have emerged from these findings, including the communication through coherence hypothesis, which proposes that synchronous oscillations render neuronal communication effective, selective, and precise. The implications of such a theory may be universal for brain function, as the determinants of neuronal communication inextricably shape the neuronal representation of information in the brain. However, the study …

Mild Traumatic Brain Injury With Associated Visual System Dysfunction: Investigating Histopathology, Functional Correlates, And A Novel Therapeutic Immune Modulator, Natalie M. Guley

Theses and Dissertations (ETD)

Background. Traumatic brain injury (TBI) is a significant source of morbidity and mortality worldwide. Injuries associated with moderate to severe TBI can be profound, and have historically overshadowed the significant impact mild TBI (mTBI) can have on the lives of affected individuals. Mild TBI can manifest in a number of different ways, but one of the most significant and often debilitating is its impact on the visual system. In order to further investigate the underlying pathology of mTBI and test potential therapeutics, we developed a mouse model of mTBI induced by blast overpressure. In this model, a 50-60 psi …

Adenosine Production Is Essential For Closing The Critical Period Of Cortical Plasticity, Rachel A. Chassan

Theses and Dissertations (ETD)

Sensory inputs from the external world are represented as highly organized systems in the adult brain for effective adaptation to the environment. At the cortical level, this organization is referred to as cortical maps. The establishment of cortical maps begins with early life experiences during the critical period, a brief period during development of heightened sensitivity to sensory stimuli. During this time, organization of cortical maps is plastic and highly subject to change through passive sensory experience. As an animal matures, the critical period closes and changes to cortical maps occur less freely. The cellular mechanisms of cortical map plasticity …

Metabotropic Glutamate Receptor 5 In The Medial Prefrontal Cortex: Role In Cocaine Sensitization And Addiction, Kristin Marie Timmer

Theses and Dissertations (ETD)

Cocaine sensitization is associated with cocaine-induced hyperexcitability of pyramidal projection neurons within the medial prefrontal cortex (mPFC). Such hyperexcitability presumably results in increased glutamatergic input to reward-affiliated brain regions such as the ventral tegemental area (VTA) and nucleus accumbens (NAc), consequently facilitating drugseeking behavior. Metabotropic glutamate receptor 5 (mGluR5) has been implicated in cocaine addiction and demonstrated to increase neuronal excitability, therefore, the aim of the present study was to investigate the effect of intra-mPFC mGluR5 manipulation on behavioral and neurochemical sensitization and drug-seeking. Bilateral cannulae were implanted into the mPFC of male Sprague-Dawley rats and mGluR5 antagonist MTEP (15 …

Characterizing Purkinje Cell Responses And Cerebellar Influence On Fluid Licking In The Mouse, Jeri Lonece Bryant

Theses and Dissertations (ETD)

Rodents consume water by performing stereotypical, rhythmic licking movements which are believed to be driven by central pattern generating circuits located in the brainstem. Temporal aspects of rhythmic licking behavior have been shown to be represented in the olivo-cerebellar system in the form of population complex spike activity. These findings suggest that the olivo-cerebellar system is involved in the generating circuitry responsible for licking rhythm in rodents. However, the representation of licking in the simple spike activity of Purkinje cells and the consequences of loss of cerebellar function on licking behavior has not been quantified. I investigated the influence of …

The Combined Effect Of In-Situ Tumor And Irradiation On Peritumoral Brain Vasculature, Janice Ann Zawaski

Theses and Dissertations (ETD)

In the USA, 200,000 brain tumors are diagnosed each year with glioma representing 8.4% of the 200,000. The standard treatment for glioma consists of surgical resection, when possible, followed by radiation therapy (RT) and/or chemotherapy. Radiation therapy is one of the most effective treatments of brain tumors; however, the therapeutic ratio of RT is limited by damage to the normal tissue. We hypothesize that tumor growth has an adverse effect on the peritumoral tissue through the angiogenic/inflammatory environment it creates rendering it susceptible to further damage by RT which may be prevented by using anti-angiogenic/anti-inflammatory agents. We have developed a …

Neuroadaptive Changes In The Mesocortical Glutamatergic System During Nicotine Self-Administration And After Extinction In Rats, Fan Wang

Theses and Dissertations (ETD)

The mesocorticolimbic pathway is critical in almost all aspects of drug abuse, including nicotine. Though many of the neurochemical and molecular effects of nicotine have been well studied, nicotine’s long-term neuroadaptive effects, specifically within the mesocorticolimbic pathway, are largely undefined. Thus, in current study, we determined the neuroadaptive changes in the mesocortical glutamatergic system during chronic nicotine self-administration (SA), which emulates important aspects of nicotine intake by humans, and after extinction. In the initial study, after 18 days of nicotine SA, in the medial prefrontal cortex (mPFC), NMDA receptor subunit 2A (NR2A) and NR2B were increased by 67% and 83%, …

Role Of Medial Prefrontal Cortical Group Ii Metabotropic Glutamate Receptor In The Development Of Cocaine Sensitization, Xiaohu Xie

Theses and Dissertations (ETD)

The current studies examined the role of medial prefrontal cortical (mPFC) group II metabotropic glutamate receptors (mGluR_2/3) in the development of cocaine sensitization. Initial studies demonstrated that intra-mPFC injection of the mGluR_2/3 receptor agonist, APDC, dose-dependently reduced acute behavioral response to cocaine (0.015-15 nmol/side with significant effects starting at 1.5nmol/side). The effects of APDC were prevented by intra-mPFC co-injections of an mGluR_2/3 antagonist, LY341495 (1.5 nmol/side). Repeated intra-mPFC APDC (1.5 nmol/side) injections also prevented the initiation of behavioral and neurochemical sensitization, which is defined as enhanced nucleus accumbens (NAc) dopamine response to cocaine. Once sensitization was …

Effect Of Background Synaptic Activity On Excitatory-Postsynaptic Potential-Spike Coupling, Veronika Zsiros

Theses and Dissertations (ETD)

Neurons receive large amount of synaptic inputs in vivo, which may impact the coupling between EPSPs and spikes. We mimicked the in vivo synaptic activity of the cell with the dynamic clamp system. We recorded from pyramidal cells in neocortical slices in vitro to investigate how timing and probability of spike generation in response to an EPSP is affected by background synaptic conductance under these conditions. We found that near threshold, background synaptic conductance improved the precision of spike timing by reducing the depolarization-related prolongation of the EPSP. In cells with ongoing spike activity and background synaptic conductances, an …

Genetic Control Of Eye Development, A Case Study Focused On The Murine Mutation Belly Spot And Tail (Bst), Qing Tang

Theses and Dissertations (ETD)

Development of the eye is controlled by a network of genes, often conserved, that regulate the timing and location of cellular differentiation. One approach to understanding this network of genes and their interaction is to focus on mutations, spontaneous or induced, that predictably disrupt the proper function of such networks, and by examining the effect of such disruption on the function of other genes.

The Belly spot and tail (Bst) semi-dominant mutation, mapped to mouse Chromosome 16, leads to developmental defects of the eye, skeleton, and coat pigmentation. In the eye, the mutant phenotype is characterized by the presence of …