Neurosciences Commons^™

The Mglur2/3 Agonist Ly397268 Improves Morphometric And Behavioral Outcomes In R6/2 Huntington's Disease Mice, Dennis Craig Lafferty

Theses and Dissertations (ETD)

A prominent theory for the pathology of Huntington's Disease (HD) is the excitotoxic injury to the striatum. Continual exposure of ionotropic NMDA receptors to glutamate from the cortex can be excitotoxic in HD and leave striatal neurons vulnerable to damage. Activation of presynaptic mGluR2/3 by an agonist dampens glutamate release from corticostriatal terminals. Treatments that target excitoxicity and oxidative stress thus may improve some of the symptoms in HD patients and it is therefore logical to pursue therapies aimed in this direction. LY379268 is an inviting mGluR2/3 agonist that has been shown to be neuroprotective in hypoxic and ischemic injuries …

Protocol Variation Analysis Of Whole Brain Ct Perfusion In Acute Ischemic Stroke, Peter T. Heiberger

UNLV Theses, Dissertations, Professional Papers, and Capstones

Computed tomography perfusion (CTP) analysis is a rapidly advancing imaging modality that is improving diagnosis of brain abnormalities in patients suffering from hemorrhagic or ischemic stroke, traumatic brain injury, vascular occlusion and numerous other conditions. Through the advancements of computed tomography (CT) imaging, including the introduction of the 320-detector row CT with a 16 centimeter range in the z-axis enabling whole brain CTP, perfusion analysis now has a significantly increased clinical utility that is useful for both diagnosis and treatment of central nervous system (CNS) conditions. This study focuses on the procedural and analytical approach to the diagnostic evaluation of …

Donepezil And Galanin Interactions In An Animal Model Of Alzheimer’S Disease, Jonathan J. Sabbagh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer's disease (AD) is a neurodegenerative disorder marked by a progressive loss of cognitive function. One of the neurobiological hallmarks of AD is a progressive loss of cholinergic neurons and a decrease in the amount of acetylcholine in the brain. Pharmacological therapies have targeted the cholinergic system, specifically first-line, palliative treatment using acetylcholinesterase (AChE) inhibitors, such as donepezil. Donepezil has been shown to increase cholinergic tone and ameliorate some of the cognitive deficits in AD patients. Galanin, a neuropeptide that inhibits the evoked release of several neurotransmitters including acetylcholine as well as modulates seveal intracellular cascades, is overexpressed in AD …

Fat Taste Transduction In Mouse Taste Cells: The Role Of Transient Receptor Potential Channel Type M5, Pin Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A number of studies have demonstrated the ability of free fatty acids to activate taste cells and elicit behavioral responses consistent with there being a taste of fat. Here I show for the first time that long chain unsaturated free fatty acid, linoleic acid, depolarizes taste cells and elicits a robust intracellular calcium rise via the activation of transient receptor potential channel type M5. The linoleic acid-induced responses depend on G protein-phospholipase C pathway indicative of the involvement of G protein-coupled receptors in the transduction of fatty acids. Mice lacking transient receptor potential channel type M5 exhibit no preference for …

Failing To Ignore: Paradoxical Neural Effects Of Perceptual Load On Early Attentional Selection In Normal Aging, Taylor W. Schmitz, Frederick H.T. Cheng, Eve De Rosa

Brain and Mind Institute Researchers' Publications

We examined visual selective attention under perceptual load - simultaneous presentation of task-relevant and -irrelevant information - in healthy young and older adult human participants to determine whether age differences are observable at early stages of selection in the visual cortices. Participants viewed 50/50 superimposed face/place images and judged whether the faces were male or female, rendering places perceptible but task-irrelevant. Each stimulus was repeated, allowing us to index dynamic stimulus-driven competition from places. Consistent with intact early selection in young adults, we observed no adaptation to unattended places in parahippocampal place area (PPA) and significant adaptation to attended faces …

Chronic Spontaneous Activity Generated In The Somata Of Primary Nociceptors Is Associated With Pain-Related Behavior After Spinal Cord Injury, Supinder S Bedi, Qing Yang, Robyn J Crook, Junhui Du, Zizhen Wu, Harvey M Fishman, Raymond J Grill, Susan M Carlton, Edgar T Walters

Faculty, Staff and Student Publications

Mechanisms underlying chronic pain that develops after spinal cord injury (SCI) are incompletely understood. Most research on SCI pain mechanisms has focused on neuronal alterations within pain pathways at spinal and supraspinal levels associated with inflammation and glial activation. These events might also impact central processes of primary sensory neurons, triggering in nociceptors a hyperexcitable state and spontaneous activity (SA) that drive behavioral hypersensitivity and pain. SCI can sensitize peripheral fibers of nociceptors and promote peripheral SA, but whether these effects are driven by extrinsic alterations in surrounding tissue or are intrinsic to the nociceptor, and whether similar SA occurs …

Dysregulation Of The Mitogen Granulin In Human Cancer Through The Mir-15/107 Microrna Gene Group, Wang-Xia Wang, Natasha Kyprianou, Xiaowei Wang, Peter T. Nelson

Pathology and Laboratory Medicine Faculty Publications

Granulin (GRN) is a potent mitogen and growth factor implicated in many human cancers, but its regulation is poorly understood. Recent findings indicate that GRN is regulated strongly by the microRNA miR-107, which functionally overlaps with miR-15, miR-16, and miR-195 due to a common 5′ sequence critical for target specificity. In this study, we queried whether miR-107 and paralogs regulated GRN in human cancers. In cultured cells, anti-argonaute RNA coimmunoprecipitation with downstream microarray analyses indicates that GRN mRNA is directly targeted by numerous miR-15/107 miRNAs. We further tested this association in human tumors. MiR-15 and miR-16 are known to be …

Characterization And Development Of A Stroke-Induced Model Of Acquired Epilepsy In Organotypic Hippocampal Slice Cultures: Role Of The Cannabinoid Cb1 Receptors In Modulation Of Neuronal Excitation And Inhibition, Julie Ziobro

Theses and Dissertations

Stroke is the most common cause of acquired epilepsy in persons 35 and older. The massive increase in extracellular glutamate during stroke causes a cascade of intracellular events that can lead to cell death or the molecular changes that initiate the development of epilepsy. In addition, many studies point to a modulatory role of the endocannabinoid system in controlling seizures. Animal models of stroke induced acquired epilepsy have been difficult to develop. Therefore, this dissertation was initiated to develop an organotypic hippocampal slice culture model of acquired epilepsy and examine the changes in distribution and function of the endogenous CB1 …

Neural Coding And Decoding, Alexander Dimitrov

Systems Science Friday Noon Seminar Series

Methods based on Rate Distortion theory have been successfully used to cluster stimuli and neural responses in order to study neural codes at a level of detail supported by the amount of available data. They approximate the joint stimulus-response distribution by quantizing paired stimulus-response observations into smaller reproductions of the stimulus and response spaces. An optimal quantization is found by maximizing an information-theoretic cost function subject to both equality and inequality constraints, in hundreds to thousands of dimensions. This analytical approach has several advantages over other current approaches:

• it yields the most informative approximation of the encoding scheme given the …

Pontine Haemorrhage Due To Chondrosarcoma Of The Skull Base, Maliha Iqbal Jumani, Roomasa Channa, Sayed Nabeel Zafar, Ather Enam

Section of Neurosurgery

A young adult presented with acute weakness of right side of body and slurring of speech. An initial brain CT scan showed a pontine haemorrhage, however MRI done a few days later revealed a mass in the left parapharyngeal space. Histopathology of the mass revealed that it was a chondrosarcoma. Subsequently the patient was initially treated with chemotherapy and radiotherapy and later surgery. Skull base chondrosarcomabe is to be included in the differentials of a young patient presenting with signs consistent with pontine haemorrhage.

The Mir-15/107 Group Of Microrna Genes: Evolutionary Biology, Cellular Functions, And Roles In Human Diseases, John R. Finnerty, Wang-Xia Wang, Sébastien S. Hébert, Bernard R. Wilfred, Guogen Mao, Peter T. Nelson

Pathology and Laboratory Medicine Faculty Publications

The miR-15/107 group of microRNA (miRNA) gene is increasingly appreciated to serve key functions in humans. These miRNAs regulate gene expression involved in cell division, metabolism, stress response, and angiogenesis in vertebrate species. The miR-15/107 group has also been implicated in human cancers, cardiovascular disease and neurodegenerative disease, including Alzheimer's disease. Here we provide an overview of the following: (1) the evolution of miR-15/107 group member genes; (2) the expression levels of miRNAs in mammalian tissues; (3) evidence for overlapping gene-regulatory functions by different miRNAs; (4) the normal biochemical pathways regulated by miR-15/107 group miRNAs; and (5) the roles played …

Microrna-21 Dysregulates The Expression Of Mef2c In Neurons In Monkey And Human Siv/Hiv Neurological Disease., Sowmya V. Yelamanchili, A Datta Chaudhuri, L N. Chen, Huangui Xiong, Howard S. Fox

Journal Articles: Pharmacology & Experimental Neuroscience

MicroRNAs (miRNAs) play important roles in regulating a plethora of physiological and pathophysiogical processes including neurodegeneration. In both HIV associated dementia in humans and its monkey model SIV encephalitis we find miR-21, a miRNA largely known for its link to oncogenesis, to be significantly upregulated in the brain. In situ hybridization of the diseased brain sections revealed induction of miR-21 in neurons. MiR-21 can be induced in neurons by prolonged N-methyl-D-aspartic acid receptor stimulation, an excitotoxic process active in HIV and other neurodegenerative diseases. Introduction of miR-21 into human neurons leads to pathological functional defects. Furthermore, we show that miR-21 …

Effects Of Hypothyroidism On Cell Proliferation And Neuroblasts In The Hippocampal Dentate Gyrus In A Rat Model Of Type 2 Diabetes, Sun Shin Yi, In Koo Hwang, Ji Won Choi, Moo-Ho Won, Je Kyung Seong, Yeo Sung Yoon

Biomedical Sciences Faculty Research and Publications

We observed how the hypothyroid state affects diabetic states and modifies cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG). For this, 0.03% methimazole, an anti-thyroid drug, was administered to 7-week-old, pre-diabetic Zucker diabetic fatty (ZDF) rats by drinking water for 5 weeks, and the animals were sacrificed at 12 weeks of age. At this age, corticosterone levels were significantly increased in the ZDF rats compared to those in the control (Zucker lean control, ZLC) rats. Methimazole (methi) treatment in the ZDF rats (ZDF-methi rats) significantly decreased corticosterone levels and diabetes-induced hypertrophy of adrenal glands. In the DG, …

Molecular Requirements For Ethanol Differential Allosteric Modulation Of Ligand-Gated Ion Channels Based On Selective Gβγ Modulation, Gonzalo E. Yevenes, Gustavo Moraga-Cid, Ariel Avila, Leonardo Guzman, Maximiliano Figueroa, Robert W. Peoples, Luis G. Aguayo

Biomedical Sciences Faculty Research and Publications

It is now believed that the allosteric modulation produced by ethanol in glycine receptors (GlyRs) depends on alcohol binding to discrete sites within the protein structure. Thus, the differential ethanol sensitivity of diverse GlyR isoforms and mutants was explained by the presence of specific residues in putative alcohol pockets. Here, we demonstrate that ethanol sensitivity in two LGIC members, the GlyR adult α₁ and embryonic α₂ subunits, can be modified through selective mutations that rescued or impaired Gβγ modulation. Even though that both isoforms were able to physically interact with Gβγ, only the α₁ GlyR was functionally …

Distinct Macrophage Subpopulations Regulate Viral Encephalitis But Not Viral Clearance In The Cns, Christina D. Steel, Woong-Ki Kim, Larry Sanford, Laurie Wellman, Sandra Burnett, Nico Van Rooijen, Rochard P. Ciavarra

Biological Sciences Faculty Publications

Intranasal application of vesicular stomatitis virus (VSV) induces acute encephalitis characterized by a pronounced myeloid and T cell infiltrate. The role of distinct phagocytic populations on VSV encephalitis was therefore examined in this study. Ablation of peripheral macrophages did not impair VSV encephalitis or viral clearance from the brain, whereas, depletion of splenic marginal dendritic cells impaired this response and enhanced morbidity/mortality. Selective depletion of brain perivascular macrophages also suppressed this response without altering viral clearance. Thus, two anatomically distinct phagocytic populations regulate VSV encephalitis in a non-redundant fashion although neither population is essential for viral clearance in the CNS. …

Transcriptional Profiles For Glutamate Transporters Reveal Differences Between Organophosphates But Similarities With Unrelated Neurotoxicants, Theodore A. Slotkin, Doug Lobner, Frederic J. Seidler

Biomedical Sciences Faculty Research and Publications

The developmental neurotoxicity of organophosphates involves mechanisms other than their shared property as cholinesterase inhibitors, among which are excitotoxicity and oxidative stress. We used PC12 cells as a neurodevelopmental model to compare the effects of chlorpyrifos and diazinon on the expression of genes encoding glutamate transporters. Chlorpyrifos had a greater effect in cells undergoing nerve growth factor-induced neurodifferentiation as compared to undifferentiated PC12 cells, with peak sensitivity at the initiation of differentiation, reflecting a global upregulation of all the glutamate transporter genes expressed in this cell line. In differentiating cells, chlorpyrifos had a significantly greater effect than did diazinon and …

Neural Reuse: A Fundamental Organizational Principle Of The Brain, Michael Anderson

Brain and Mind Institute Researchers' Publications

An emerging class of theories concerning the functional structure of the brain takes the reuse of neural circuitry for various cognitive purposes to be a central organizational principle. According to these theories, it is quite common for neural circuits established for one purpose to be exapted (exploited, recycled, redeployed) during evolution or normal development, and be put to different uses, often without losing their original functions. Neural reuse theories thus differ from the usual understanding of the role of neural plasticity (which is, after all, a kind of reuse) in brain organization along the following lines: According to neural reuse, …

Multiple Mechanisms Of Consciousness: The Neural Correlates Of Emotional Awareness., Jayna M Amting, Steven G Greening, Derek G V Mitchell

Brain and Mind Institute Researchers' Publications

Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally, …

Passive Transfer Of Igg Anti-Gm1 Antibodies Impairs Peripheral Nerve Repair, Pablo H Lopez, Gang Zhang, Jiangyang Zhang, Helmar C Lehmann, John W Griffin, Ronald L Schnaar, Kazim A Sheikh

Faculty, Staff and Student Publications

Anti-GM1 antibodies are present in some patients with autoimmune neurological disorders. These antibodies are most frequently associated with acute immune neuropathy called Guillain-Barré syndrome (GBS). Some clinical studies associate the presence of these antibodies with poor recovery in GBS. The patients with incomplete recovery have failure of nerve repair, particularly axon regeneration. Our previous work indicates that monoclonal antibodies can inhibit axon regeneration by engaging cell surface gangliosides (Lehmann et al., 2007). We asked whether passive transfer of human anti-GM1 antibodies from patients with GBS modulate axon regeneration in an animal model. Human anti-GM1 antibodies were compared with other GM1 …

Neural Plasticity And Treatment-Induced Recovery Of Sentence Processing In Agrammatism, Cynthia K. Thompson, Dirk B. Den Ouden, Borna Bonakdarpour, Kyla Garibaldi, Todd B. Parrish

Communication Sciences and Disorders Faculty Articles and Research

This study examined patterns of neural activation associated with treatment-induced improvement of complex sentence production (and comprehension) in six individuals with stroke-induced agrammatic aphasia, taking into account possible alterations in blood flow often associated with stroke, including delayed time-to-peak of the hemodynamic response function (HRF) and hypoperfused tissue. Aphasic participants performed an auditory verification fMRI task, processing object cleft, subject cleft, and simple active sentences, prior to and following a course of Treatment of Underlying Forms (TUF; Thompson et al., 2003), a linguistically based approach for treating aphasic sentence deficits, which targeted object relative clause constructions. The patients also were …