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Recovery From Visual Dysfunction Following Mild Traumatic Brain Injury Is Associated With Adaptive Reorganization Of Retinal Inputs To Lateral Geniculate Nucleus In The Mouse Model Utilizing Central Fluid Percussion Injury., Vishal C. Patel

Theses and Dissertations

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality nationwide. Prevalence of mild TBI (mTBI) vastly outnumbers more severe forms however the associated morbidity has only recently gained public attention. Visual dysfunction is a significant component of mTBI associated morbidity with recovery of function linked with improvement in global outcomes. Examination of sensory and motor pathways in other brain injury paradigms support that recovery is largely dependent on adaptive plasticity of remaining connections. Current examinations of visual function recovery following mTBI is limited to identifying evidence for recovery and objective evidence for adaptive plasticity is limited. Therefore, …

Elucidating The Role Of Injury-Induced Electric Fields (Efs) In Regulating The Astrocytic Response To Injury In The Mammalian Central Nervous System, Matthew L. Baer, Scott C. Henderson, Raymond J. Colello

Anatomy and Neurobiology Publications

Injury to the vertebrate central nervous system (CNS) induces astrocytes to change their morphology, to increase their rate of proliferation, and to display directional migration to the injury site, all to facilitate repair. These astrocytic responses to injury occur in a clear temporal sequence and, by their intensity and duration, can have both beneficial and detrimental effects on the repair of damaged CNS tissue. Studies on highly regenerative tissues in non-mammalian vertebrates have demonstrated that the intensity of direct-current extracellular electric fields (EFs) at the injury site, which are 50–100 fold greater than in uninjured tissue, represent a potent signal …

Structural Alterations To The Axon Initial Segment Following Diffuse Axonal Injury As A Consequence Of Age, William Behl

Theses and Dissertations

An epidemiological shift towards the elderly population has occurred in traumatic brain injury (TBI). Age is believed to be one of the strongest prognostic indicators following TBI. Diffuse axonal injury (DAI), a prevalent feature of TBI, is believed to be the primary cause for much of the morbidity and mortality associated with TBI. The pathobiology associated with DAI is believed to occur in response to the primary injury in a progressive, secondary fashion. Though the injury mechanisms behind DAI have been shown to occur at numerous sites along the axon, recent work suggests that the axon initial segment (AIS) may …

Inhibition Of Injury-Induced Cell Proliferation In The Dentate Gyrus Impairs Cognitive Recovery Following Traumatic Brain Injury, Teresa Daniels

Theses and Dissertations

Traumatic brain injury (TBI) induces a robust cellular proliferative response among neural stem/progenitor cells (NS/NPCs) in the dentate gyrus of the hippocampus. This proliferative effect is thought to contribute to the innate cognitive recovery observed following TBI. Inhibition of hippocampal neurogenesis impairs cognitive function. Furthermore, enhancement of injury-induced hippocampal neurogenesis via intraventricular administration of basic fibroblast growth factor (bFGF) improves cognitive function in animals following TBI. In this experiment, we investigated the direct association between injury-induced hippocampal neurogenesis and cognitive recovery utilizing an antimitotic agent, arabinofuranosyl cytidine (Ara-C). In this study, adult rats received a moderate lateral fluid percussion injury …

The Effect Of Minocycline Treatment On Cell Proliferation And Neurogenesis In The Hippocampus In Young And Aged Brains Following Traumatic Brain Injury, Ashley Harvin

Theses and Dissertations

Following traumatic brain injury, there is an enhanced cell proliferative and neurogenic response in the young adult hippocampus, which may be associated with innate cognitive recovery. However, in the aged brain, an increased level of inflammatory cell responses was observed following injury concomitant to decreased hippocampal neurogenesis and cognitive recovery in the aging population. This suggests that excessive inflammation produced in the injured aging brain has a detrimental effect on neurogenesis and cognitive function. In this study, we examined the effect of anti-inflammatory treatment with minocycline on cell proliferation and generation of new neurons in the dentate gyrus (DG) of …

Early Hearing-Impairment Results In Crossmodal Reorganization Of Ferret Core Auditory Cortex, M. Alex Meredith, Brian L. Allman

Anatomy and Neurobiology Publications

Numerous investigations of cortical crossmodal plasticity, most often in congenital or early-deaf subjects, have indicated that secondary auditory cortical areas reorganize to exhibit visual responsiveness while the core auditory regions are largely spared. However, a recent study of adult-deafened ferrets demonstrated that core auditory cortex was reorganized by the somatosensory modality. Because adult animals have matured beyond their critical period of sensory development and plasticity, it was not known if adult-deafening and early-deafening would generate the same crossmodal results. The present study used young, ototoxically-lesioned ferrets () that, after maturation (avg. = 173 days old), showed significant hearing deficits (avg. …

The Effects Of Sdf-1Α Treatment On The Migration Of Neural Stem/Progenitor Cells After Traumatic Brain Injury, Corey Evans

Theses and Dissertations

Traumatic Brain Injury (TBI) is one of the leading causes of death and disability among young adults and has been a significant field in medical research over the past decades. Intensive studies focusing on how to repair tissue damage resulting from head injuries have discovered that the central nervous system (CNS) retains a regenerative capacity throughout life due to the persistent presence of neural stem/progenitor cells (NS/NPCs) in the neurogenic regions. In the normal brain, cells generated in the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) to the olfactory bulb and cells in the subgranular zone (SGZ) …

The Effects Of Bfgf Treatment In The Aged Brain Following Traumatic Brain Injury, Michael Zeigler

Theses and Dissertations

The mature mammalian brain continually generates new neurons in the subventricular zone and hippocampus throughout life. Adult neurogenesis in the hippocampus is associated with hippocampal-dependent learning and memory function. During aging, this endogenous neurogenic potential is reduced which is accompanied by decreased cognitive function seen in the aging population. We have previously found that the injured adult brain shows heightened levels of endogenous neurogenesis and this response is associated with innate cognitive recovery. We have also found that basic fibroblast growth factor (bFGF), a potent neurotrophic polypeptide, can enhance injury-induced hippocampal neurogenesis and improve cognitive recovery following TBI. In this …

Modeling Pure Vasogenic Edema In The Rat Brain, Charles Nottingham

Theses and Dissertations

Targeted drug delivery to the brain is difficult to achieve using conventional techniques, largely due to the blood-brain barrier’s (BBB) impediment to drug diffusion into the brain parenchyma. In response, development of convection-enhanced delivery (CED) offers the ability to circumvent the BBB and target specific areas of the brain. Predictability of infusate movement in pathological brain states during CED will maximize the effectiveness of this treatment, and therefore modeling of infusate movement must be characterized. Previous work from our lab effectively modeled CED in rats using the middle carotid artery occlusion model of cytotoxic edema. However, previous models examined for …

Status Epilepticus Results In A Duration-Dependent Increased Protein Kinase A Activity In The Rat Pilocarpine Model, James M. Bracey

Theses and Dissertations

This study was conducted to characterize cellular changes occurring during the progression of status epilepticus (SE) that could lead to the maintenance of increased membrane excitability. SE was induced by injection of pilocarpine after which rats were monitored both electrographically and behaviorally. After various lengths of time in SE, specific brain regions were isolated for biochemical study. SE resulted in an early maintenance of PKA activity in both cortical homogenate and crude synaptoplasmic membrane (crude SPM) fractions. At subsequent stages of SE there was a significant increase in PKA activity in both homogenate and crude SPM fractions. Wester blot analysis …

Supramedullary Afferents To The Nucleus Raphe Magnus In The Rat: A Study Using Transcannula Hrp-Gel And Autoradiography Techniques, Susan Mary Carlton

Theses and Dissertations

The nucleus raphe magnus (NRM) is known to play an important role in a descending antinociceptive system through its projections to the spinal cord dorsal horn and trigeminal subnucleus caudalis. Identifying those nuclei which project to NRM is essential in determining other CNS cell groups which could influence analgesic mechanisms by virtue of their connections with NRM.

In an attempt to define NRM afferents, 19 adult Sprague-Dawley rats were stereotaxically implanted with a pellet of HRP gel within NRM and in adjacent areas. A transcannula technique was specifically developed for the subcortical placement of HRP in a gel form. Use …

The Morphologic Changes In The Muscles Of Mastication Due To Direct Intramuscular Injection Of Lidocaine, Carbocaine, Procaine And Citanest, Kurt Elliot Friedman

Theses and Dissertations

One of the most commonly experienced symptoms in dentistry and one that is of major concern to the dentist is pain. Since pain is manifested when an environmental change occurs causing injury to responsive tissues, it is often spoken of as a protective mechanism.

Pain has been described by a variety of terms: sharp, burning, aching, cramping, dull and throbbing! (Monheim, 1969). Therefore, it is a difficult term to define. Monheim (1969) describes pain as an unpleasant sensation created by a noxious stimulus that is mediated along specific nerve pathways into the central nervous system, where it is interpreted as …

Corticospinal Fibers In A Prosimian Primate, Galago, George Edward Goode

Theses and Dissertations

The function of the central nervous system cannot be understood from inspection of a single region, for each cell and fiber has discrete connections. Therefore, a study of the nervous system requires distinct approaches. One fundamental approach has been the study of comparative neuroanatomy.

In a comparative study of the evolution of the primates and subsequently man, the investigator is confronted with a variety of animal forms. Each form represents an end product of a long vertical line of evolutionary development. The problem is to try to reconstruct the vertical line (ancestral forms) from the horizontal end products (extant forms). …