Other Neuroscience and Neurobiology Commons^™

Improving Dopamine Monitoring With Ncam And The Effects Of Intranasal Oxytocin On Dopamine Signaling In The Rat Brain, Darren Earl Ginder

EWU Masters Thesis Collection

Dopamine (DA) is a neurohormone highly involved in learning and memory. Oxytocin (OXT), another neurohormone, has also been implicated in learning and memory. Fast-scan cyclic voltammetry (FSCV) is a method used for the real-time examination of DA neurotransmission in the brain. Implanting FSCV electrodes is an invasive technique that likely results in an inflammatory response (i.e. gliosis) that can restrict FSCV recording of DA signals. Neural cell adhesion molecule (NCAM) may reduce gliosis and potentially improve the ability of FSCV electrodes to monitor DA signaling. Chapter 1 Methods: FSCV electrodes were coated with NCAM and implanted in the rat brain. …

Sodium Channel Distribution In The Apical Dendrites Of Pyramidal Cells Vary In The Hindbrain Of Apteronotus Leptorhynchus., Sree Indrani Motipally

Graduate Theses, Dissertations, and Problem Reports (ETD)

Apteronotid weakly electric fish heavily rely on their electrosensory system for behaviors like spatial navigation, communication and prey capture. Since the behaviorally important information about their environment is contained in the spatial and temporal modulations of the electrosensory signal, efficient mechanisms to process this information with great fidelity are of the utmost importance. Efficient sensory processing often involves having multiple parallel processing streams so that each stream can specialize to treat signals with different properties. This strategy requires the response properties and neural dynamic to be adjusted in each pathway to implement different neural coding strategies. One of the neural …

Modeling And Mapping Addiction In The Zebrafish, Danio Rerio, Bradley Serpa

Master of Science in Integrative Biology Theses

Driven by the communication of dopamine, the vertebrate reward system has been evolutionarily conserved to maintain survival and optimize fitness. The neural circuits governing this system integrate sensory stimuli to produce appropriate, self-preserving responses that underlie experience-based learning. In the most primitive vertebrates, dopamine release in neuronal circuits drives homeostatic behaviors, such as seeking nutrients, finding a mate, or avoiding danger. From agnathans to mammals, dopaminergic synthesis and signaling genes and molecules, along with neuronal pathways and reward system-based behaviors, remain highly conserved. Dopamine signaling proteins include two classes of metabotropic G-Protein Receptor Coupled Dopamine Receptors, D1-like (DRD1) and D2-like …

Endocytosis And The Nitric Oxide-Dependent Release Of Chloride, Vernon K. Dunn Jr

LSU Doctoral Dissertations

Understanding the regulation of retinal synapses is a key step in elucidating the processing of information in the retina. Our lab has previously shown that nitric oxide (NO) can alter the synaptic response properties of amacrine cells by releasing Cl- from internal acidic compartments. This alteration in the Cl- gradient brings about a positive shift in the reversal potential of the GABA-gated current, which can convert inhibitory synapses into excitatory synapses. Recently, we have shown that the cystic fibrosis transmembrane regulator (CFTR) Cl- channel is involved in the Cl- release. Here, we test the hypothesis that (acidic) synaptic vesicles are …

Is Concussion-Related Sleep Disturbance Present After Return To Play In College Athletes?, Alexander Gallaer

Honors Scholar Theses

As one of the most commonly experienced symptoms, the ramifications of sleep disruption as a result of concussion are potentially great, yet widely unexplored. Particularly troublesome is murky data regarding the length of sleep disruption following a concussion. By analyzing self-reported sleep data via the Pittsburgh Sleep Quality Index, this study seeks to investigate potential differences in sleep quality between injured college athletes 40 days after they have been cleared to play and matched controls. Data was analyzed using ANOVA analysis as well as Pearson correlation. No significant differences were found in sleep quality between groups, nor was there a …

Spinal Cord Trauma: An Overview Of Normal Structure And Function, Primary And Secondary Mechanisms Of Injury, And Emerging Treatment Modalities, Daniel Morin

Senior Honors Theses

The structures of the spinal cord and vertebral column are designed to provide flexibility, while still providing ample protection for the spinal cord deep within. While it does offer remarkable protection against most routine trauma, the spinal cord is still vulnerable to high-force etiologies of trauma and may become damaged as a result. These events are referred to as primary injury. Following the initial injury, the body’s own physiological responses cause a cascade of deleterious effects, known as secondary injury. Secondary injury is a major therapeutic target in mitigating the effects of spinal cord injury (SCI), and much research is …

Characterization Of The Roles Of Muscle-Synthesized Brain-Derived Neurotrophic Factor And Presynaptic Tyrosine Receptor Kinase B In Motor Neuron Axonal Transport, Luke A. Vanosdol

All NMU Master's Theses

Brain-derived neurotrophic factor (BDNF) is a small, diffusible protein essential for the development and function of neurons. It is synthesized by many types of tissue, including muscle. BDNF actions are mediated via binding to its receptor, tyrosine receptor kinase B (TrkB). The BDNF-TrkB complex is endocytosed into a specialized vesicle, which induces downstream signaling cascades locally in the dendrites, or, more often, is delivered to the cell soma via retrograde axonal transport, where it modulates gene expression. BDNF activation of TrkB is critical for the initiation of axonal transport, and this cellular process relies on the interaction of numerous adaptor …

Mechanisms Underlying Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Medial Prefrontal Cortex, Emily K. Stephens, Arielle L. Baker, Allan T. Gulledge

Dartmouth Scholarship

Serotonin (5-HT) selectively excites subpopulations of pyramidal neurons in the neocortex via activation of 5-HT_2A (2A) receptors coupled to G_q subtype G-protein alpha subunits. G_q-mediated excitatory responses have been attributed primarily to suppression of potassium conductances, including those mediated by K_V7 potassium channels (i.e., the M-current), or activation of non-specific cation conductances that underlie calcium-dependent afterdepolarizations (ADPs). However, 2A-dependent excitation of cortical neurons has not been extensively studied, and no consensus exists regarding the underlying ionic effector(s) involved. In layer 5 of the mouse medial prefrontal cortex, we tested potential mechanisms of serotonergic excitation …

Glutamylation Regulates Transport, Specializes Function, And Sculpts The Structure Of Cilia, Robert O'Hagan, Malan Silva, Ken Cq Nguyen, Winnie Zhang, Sebastian Bellotti, Yasmin Ramadan, David Hall, Maureen M. Barr

Department of Biology Faculty Scholarship and Creative Works

Ciliary microtubules (MTs) are extensively decorated with post-translational modifications (PTMs), such as glutamylation of tubulin tails. PTMs and tubulin isotype diversity act as a “Tubulin Code” that regulates cytoskeletal stability and the activity of MT-associated proteins such as kinesins. We previously showed that, in C. elegans cilia, the deglutamylase CCPP-1 affects ciliary ultrastructure, localization of the TRP channel PKD-2 and the kinesin-3 KLP-6, and velocity of kinesin-2 OSM-3/KIF17, while a cell-specific α-tubulin isotype regulates ciliary ultrastructure, intraflagellar transport, and ciliary functions of extracellular vesicle (EV)-releasing neurons. Here, we examine the role of PTMs and the Tubulin Code in the cililary …

Modulation Of Spasticity By Trans-Spinal Direct Current Stimulation In Animals With Spinal Cord Injury, Wagdy Mekhael

Dissertations, Theses, and Capstone Projects

Central nervous system injuries usually produce motor impairments that are exacerbated by pathologically altered muscle tone. Abnormal muscle tone interferes with voluntary movement and is associated with loss of dexterity. Prior work in our laboratory demonstrated that 30-second trans-spinal direct current (DC) stimulation can temporarily modify muscle tone in anesthetized spastic mice after spinal cord injury (SCI). These experiments described DC-induced muscle tone responses to be polarity-dependent. That is, anodal stimulation (current passed from the lumbar spine to sciatic nerve) decreased muscle tone, and cathodal stimulation (current passed from the sciatic nerve to the lumbar spine) increased it. The present …

Encoding Of Saltatory Tactile Velocity In The Adult Orofacial Somatosensory System, Rebecca Custead

College of Education and Human Sciences: Dissertations, Theses, and Student Research

Processing dynamic tactile inputs is a key function of somatosensory systems. Spatial velocity encoding mechanisms by the nervous system are important for skilled movement production and may play a role in recovery of motor function following neurological insult. Little is known about tactile velocity encoding in trigeminal networks associated with mechanosensory inputs to the face, or the consequences of movement.

High resolution functional magnetic resonance imaging (fMRI) was used to investigate the neural substrates of velocity encoding in the human orofacial somatosensory system during unilateral saltatory pneumotactile inputs to perioral hairy skin in 20 healthy adults. A custom multichannel, scalable …

The Role Of Daf-19 In Non-Ciliated Neurons: How Is Neural Development Regulated By Different Daf-19 Isoforms?, Zabdiel Ek Vazquez

Lawrence University Honors Projects

A degenerative disease-like phenotype, specifically reduction in synaptic protein levels in adult worms, is correlated with loss-of-function of the only RFX transcription factor gene, daf-19, in C. elegans. This gene encodes four known transcription factor isoforms, two of which are correlated with particular functions. The DAF-19C isoform activates genes responsible for cilia development, while DAF-19M is needed for cilia specification in males. A comparison of the transcriptome of daf-19 null and isogenic wild type adult worms suggests both positive and negative regulation of gene expression is correlated with the presence of DAF-19 proteins. We have assessed DAF-19 regulation …

Role Of The Chondroitin Sulfate Proteoglycan, Neurocan, In Inhibition Of Sensory Neurite Regeneration, Madison Klump, Umang Khandpur, Chris Calulot, Adrian Centers, Diane M. Snow

Lewis Honors College Capstone Collection

In the adult mammalian brain and spinal cord, neuronal injury results in failed neurite regeneration, in part due to the up-regulation of chondroitin sulfate proteoglycans (CSPGs). CSPGs are molecules consisting of a protein core with covalently bound glycosaminoglycans (GAGS), specifically, chondroitin sulfate side-chains. The majority of CSPGs produced after injury originate from reactive astrocytes found in the glial scar surrounding the injury site. Although this milieu is very complex and involves more than just CSPGs, axonal regrowth may be improved if the expression of specific, highly inhibitory CSPGs produced after injury were attenuated selectively. Neurocan is one type of CSPG …

Sleep Alterations In Mouse Genetic Models Of Human Disease, Mansi Sethi

Theses and Dissertations--Biology

Sleep is a process essential for the well-being of an animal and in humans as much as one-third of our life is spent in sleep. Yet, the biological need for sleep still remains a conundrum. Our knowledge of the genes influencing sleep and the mechanisms regulating the process can be advanced with the utilization of genetic and genomic approaches which, in turn, may inform us about the functions of sleep as well. With this goal, I have investigated and examined sleep-wake phenotypes for a variety of transgenic and knock out animals.

For the first part of my research (Chapter 3), …

Axon Initial Segment Loss Is Not Observed In The Hippocampus Of A Experimental Autoimmune Encephalomyelitis Mouse Model, Praveen Mohanraju

UROP Posters

The axon initial segment (AIS) is fundamental for neuronal communication and action potential initiation, a characteristic which has been shown to be disrupted in inflammatory diseases such as Multiple Sclerosis (MS). Previous work from our lab has shown AIS breakdown in layer 5 of the cortex in a mouse model of MS known as experimental autoimmune encephalomyelitis (EAE). Moreover, it was shown that AIS breakdown was independent of demyelination but temporally correlated with microglial inflammatory reactivity. In order to determine if this pathology is specific to the cortex or affects other regions of the brain, we exploited these EAE induced …

Neuron Morphology Influences Axon Initial Segment Plasticity, Allan T. Gulledge, Jaime J. Bravo

Dartmouth Scholarship

In most vertebrate neurons, action potentials are initiated in the axon initial segment (AIS), a specialized region of the axon containing a high density of voltage-gated sodium and potassium channels. It has recently been proposed that neurons use plasticity of AIS length and/or location to regulate their intrinsic excitability. Here we quantify the impact of neuron morphology on AIS plasticity using computational models of simplified and realistic somatodendritic morphologies. In small neurons (e.g., dentate granule neurons), excitability was highest when the AIS was of intermediate length and located adjacent to the soma. Conversely, neurons having larger dendritic trees (e.g., pyramidal …

Characterizing The Rogfp2-Orp1 Fluorescent Biosensor For Detecting Oxidative Stress In Mammalian Cells, Sara A. Doan, Stevie Norcross, Mathew Tantama

The Summer Undergraduate Research Fellowship (SURF) Symposium

Parkinson’s disease is a neurodegenerative disease involving the death of neurons in the substantia nigra and loss of the neurotransmitter, dopamine. The disease leads to progressive loss of motor control. Exact causes and mechanisms by which Parkinson’s disease proceeds are unknown, however, previous experiments determine oxidative stress in mitochondria as a factor that results in cell death. Strategies have been implemented to generate fluorescent biosensors to monitor reactive oxygen species (ROS) concentrations while simultaneously measuring the spatiotemporal distribution and correlation between the ROS, cellular function and organelle. Orp1, an enzyme found in yeast, is a sensitive oxidizing species and when …

Elucidating The Role Of Endogenous Electric Fields In Regulating The Astrocytic Response To Injury In The Mammalian Central Nervous System, Matthew L. Baer

Theses and Dissertations

Endogenous bioelectric fields guide morphogenesis during embryonic development and regeneration by directly regulating the cellular functions responsible for these phenomena. Although this role has been extensively explored in many peripheral tissues, the ability of electric fields to regulate wound repair and stimulate regeneration in the mammalian central nervous system (CNS) has not been convincingly established. This dissertation explores the role of electric fields in regulating the injury response and controlling the regenerative potential of the mammalian CNS. We place particular emphasis on their influence on astrocytes, as specific differences in their injury-induced behaviors have been associated with differences in the …

Activity-Dependent Serotonergic Excitation Of Callosal Projection Neurons In The Mouse Prefrontal Cortex, Emily K. Stephens, Daniel Avesar, Allan T. Gulledge

Dartmouth Scholarship

Layer 5 pyramidal neurons (L5PNs) in the mouse prefrontal cortex respond to serotonin (5-HT) according to their long-distance axonal projections; 5-HT_1A (1A) receptors mediate inhibitory responses in corticopontine (CPn) L5PNs, while 5-HT_2A (2A) receptors can enhance action potential (AP) output in callosal/commissural (COM) L5PNs, either directly (in “COM-excited” neurons), or following brief 1A-mediated inhibition (in “COM-biphasic” neurons). Here we compare the impact of 5-HT on the excitability of CPn and COM L5PNs experiencing variable excitatory drive produced by current injection (DC current or simulated synaptic current) or with exogenous glutamate. 5-HT delivered at resting membrane potentials, or paired …

Fty720 (Fingolimod) Provides Insight Into The Molecular Mechanisms Of Multiple Sclerosis, Madelyn Elizabeth Crawford

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Multiple sclerosis (MS) is a neurodegenerative disorder caused by a prolonged immune- mediated inflammatory response that targets myelin. Nearly all of the drugs approved for the treatment of MS are general immunosuppressants or only function in symptom management. The oral medication fingolimod, however, is reported to have direct therapeutic effects on cells of the central nervous system in addition to immunomodulatory functions. Fingolimod is known to interact with sphingosine-1-phosphate (S1P) receptors, and the most widely- accepted theory for its mechanism of action is functional antagonism of the receptor. This review examines significant neuromodulatory effects achieved by functional antagonism of the …

Astroglial Boundary Formation And Epha4 Signaling In Neuroblast Migration, Nicholas B. Gallo

University Scholar Projects

Adult neurogenesis, the process of generating new neurons from neural precursors, is a highly complex process that is limited to two specific areas of the brain, the dentate gyrus of the hippocampus and the subventricular zone (SVZ). Despite continued research investigating neurogenesis in these two regions, we still lack a fundamental understanding of the molecular mechanisms of neural cell division, migration, differentiation, and integration in the postnatal brain. In particular, the rostral migratory stream (RMS), which is a cellular migratory route for newly generated neuronal precursors that travel from the SVZ to the olfactory bulb, will provide a useful model …

Astroglial Boundary Formation And Epha4 Signaling In Neuroblast Migration, Nicholas B. Gallo

Honors Scholar Theses

Adult neurogenesis, the process of generating new neurons from neural precursors, is a highly complex process that is limited to two specific areas of the brain, the dentate gyrus of the hippocampus and the subventricular zone (SVZ). Despite continued research investigating neurogenesis in these two regions, we still lack a fundamental understanding of the molecular mechanisms of neural cell division, migration, differentiation, and integration in the postnatal brain. In particular, the rostral migratory stream (RMS), which is a cellular migratory route for newly generated neuronal precursors that travel from the SVZ to the olfactory bulb, will provide a useful model …

Doxorubicin-Induced, Tnf-Α-Mediated Brain Oxidative Stress, Neurochemical Alterations, And Cognitive Decline: Insights Into Mechanisms Of Chemotherapy Induced Cognitive Impairment And Its Prevention, Jeriel T. Keeney

Theses and Dissertations--Chemistry

The works presented in this dissertation provide insights into the mechanisms of chemotherapy-induced cognitive impairment (CICI or “ChemoBrain”) and take steps toward outlining a preventive strategy. CICI is now widely recognized as a complication of cancer chemotherapy experienced by a large percentage of cancer survivors. Approximately fifty percent of existing FDA-approved anti-cancer drugs generate reactive oxygen species (ROS). Doxorubicin (Dox), a prototypical ROS-generating chemotherapeutic agent, produces the reactive superoxide radical anion (O₂^-•) in vivo. Dox treatment results in oxidation of plasma proteins, including ApoA-I, leading to TNF-α-mediated oxidative stress in plasma and brain. TNF-α elevation in brain …

Evidence For Pit-Type (Slc20) And Napi-Ii-Type (Slc34) Transporters In The Rat Choroid Plexus, Hien M. Le

Honors Scholar Theses

: A major function of the brain choroid plexus (CP) is to regulate the exchange of solutes between the blood plasma and the cerebrospinal fluid (CSF) using selective transporters. CSF inorganic phosphate (P_i) concentration is maintained at about one-half that of plasma and is potentially important because of its regulatory, structural, and biochemical functions. Phosphate is critical for ATP and DNA formation, the linked regulation between phosphate and calcium, and as an intracellular buffer. The human body has two major P_i transporter gene families known as SLC34 (NaPi-II) and SLC20 (PiT), which have wide tissue distribution. Although …

Stress-Induced Activation Of Distinct Subpopulations Of Neurons In The Basolateral Amygdala Of The Rat, Juan M. Bolanos^, Jameel N. Hamdan, Victor M. Rosales, Kristin L. Gosselink*

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Selective Serotonergic Excitation Of Callosal Projection Neurons, Daniel Avesar, Allan T. Gulledge

Dartmouth Scholarship

Serotonin (5-HT) acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs) in the mouse medial prefrontal cortex (mPFC), and found three distinct response types: long-lasting 5-HT_1A (1A) receptor-dependent inhibitory responses (84% of L5PNs), 5-HT_2A (2A) receptor-dependent excitatory responses (9%), and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%). Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM) neurons that project to the …

Orbitofrontal Cortex Provides Cross-Modal Valuation Of Self-Generated Stimuli, William A. Cunningham, Ingrid J. Haas, Ashley S. Waggoner

Department of Political Science: Faculty Publications

Prior research has shown that the orbitofrontal cortex (OFC) plays an important role in the representation of the evaluation of stimuli, regardless of stimulus modality. Based on these findings, researchers have proposed that the OFC serves a common currency function, allowing for the direct comparison of different types of perceptual stimuli (e.g. food, drink, money). The present study was designed to extend this research and investigate whether these same regions of OFC that have been identified in previous research are involved in evaluating imagined stimuli. Specifically, we asked participants to draw on prior attitudinal knowledge to generate internal representations of …