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The increase of Traumatic Brain Injury (TBI) cases in recent war history has increased the urgency of research regarding how veterans are affected by TBIs. The purpose of this study was to evaluate the effects of TBI on speech recognition in noise. The AzBio Sentence Test was completed for signal-to-noise

The increase of Traumatic Brain Injury (TBI) cases in recent war history has increased the urgency of research regarding how veterans are affected by TBIs. The purpose of this study was to evaluate the effects of TBI on speech recognition in noise. The AzBio Sentence Test was completed for signal-to-noise ratios (S/N) from -10 dB to +15 dB for a control group of ten participants and one US military veteran with history of service-connected TBI. All participants had normal hearing sensitivity defined as thresholds of 20 dB or better at frequencies from 250-8000 Hz in addition to having tympanograms within normal limits. Comparison of the data collected on the control group versus the veteran suggested that the veteran performed worse than the majority of the control group on the AzBio Sentence Test. Further research with more participants would be beneficial to our understanding of how veterans with TBI perform on speech recognition tests in the presence of background noise.
ContributorsCorvasce, Erica Marie (Author) / Peterson, Kathleen (Thesis director) / Williams, Erica (Committee member) / Azuma, Tamiko (Committee member) / Barrett, The Honors College (Contributor) / Department of Speech and Hearing Science (Contributor)
Created2015-05
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Description
Rasopathies are a family of developmental syndromes that exhibit craniofacial abnormalities, cognitive disabilities, developmental delay and increased risk of cancer. However, little is known about the pathogenesis of developmental defects in the nervous system. Frequently, gain-of-function mutations in the Ras/Raf/MEK/ERK cascade (aka ERK/MAPK) are associated with the observed pathogenesis. My

Rasopathies are a family of developmental syndromes that exhibit craniofacial abnormalities, cognitive disabilities, developmental delay and increased risk of cancer. However, little is known about the pathogenesis of developmental defects in the nervous system. Frequently, gain-of-function mutations in the Ras/Raf/MEK/ERK cascade (aka ERK/MAPK) are associated with the observed pathogenesis. My research focuses on defining the relationship between increased ERK/MAPK signaling and its effects on the nervous system, specifically in the context of motor learning. Motor function depends on several neuroanatomically distinct regions, especially the spinal cord, cerebellum, striatum, and cerebral cortex. We tested whether hyperactivation of ERK/MAPK specifically in the cortex was sufficient to drive changes in motor function. We used a series of genetically modified mouse models and cre-lox technology to hyperactivate ERK/MAPK in the cerebral cortex. Nex:Cre/NeuroD6:Cre was employed to express a constitutively active MEK mutation throughout all layers of the cerebral cortex from an early stage of development. RBP4:Cre, caMEK only exhibited hyper activation in cortical glutamatergic neurons responsible for cortical output (neurons in layer V of the cerebral cortex). First, the two mouse strains were tested in an open field paradigm to assess global locomotor abilities and overall fitness for fine motor tasks. Next, a skilled motor reaching task was used to evaluate motor learning capabilities. The results show that Nex:Cre/NeuroD6:Cre, caMEK mutants do not learn the motor reaching task, although they performed normally on the open field task. Preliminary results suggest RBP4:Cre, caMEK mutants exhibit normal locomotor capabilities and a partial lack of learning. The difference in motor learning capabilities might be explained by the extent of altered connectivity in different regions of the corticospinal tract. Once we have identified the neuropathological effects of various layers in the cortex we will be able to determine whether therapeutic interventions are sufficient to reverse these learning defects.
ContributorsRoose, Cassandra Ann (Author) / Newbern, Jason M. (Thesis director) / Olive, Foster (Committee member) / Bjorklund, Reed (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description
Neuroinflammation is an important secondary injury response occurring after traumatic brain injury (TBI). Anxiety-like disorders are commonly exacerbated after TBI and are mediated through the amygdala; however, the amygdala remains understudied despite its important contribution in processing emotional and stressful stimuli. Therefore, we wanted to study neuroinflammation after experimental TBI

Neuroinflammation is an important secondary injury response occurring after traumatic brain injury (TBI). Anxiety-like disorders are commonly exacerbated after TBI and are mediated through the amygdala; however, the amygdala remains understudied despite its important contribution in processing emotional and stressful stimuli. Therefore, we wanted to study neuroinflammation after experimental TBI using midline fluid percussion in rodent models. We assessed microglia morphology over time post-injury in two circuit related nuclei of the amygdala, the basolateral amygdala (BLA) and central amygdala of the nucleus (CeA), using skeletal analysis. We also looked at silver staining and glial fibrillary acidic protein (GFAP) to evaluate the role of neuropathology and astrocytosis to evaluate for neuroinflammation in the amygdala. We hypothesized that experimental diffuse TBI leads to microglial activation in the BLA-CeA circuitry over time post-injury due to changes in microglial morphology and increased astrocytosis in the absence of neuropathology. Microglial cell count was found to decrease in the BLA at 1 DPI before returning to sham levels by 28 DPI. No change was found in the CeA. Microglial ramification (process length/cell and endpoints/cell) was found to decrease at 1DPI compared to sham in the CeA, but not in the BLA. Silver staining and GFAP immunoreactivity did not find any evidence of neurodegeneration or activated astrocytes in the respectively. Together, these data indicate that diffuse TBI does not necessarily lead to the same microglial response in the amygdala nuclei, although an alternative mechanism for a neuroinflammatory response in the CeA likely contributes to the widespread neuronal and circuit dysfunction that occurs after TBI.
ContributorsHur, Yerin (Author) / Newbern, Jason (Thesis director) / Thomas, Theresa Currier (Committee member) / Beitchman, Joshua (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description

Traumatic brain injury (TBI) is defined as an injury to the head that disrupts normal brain function. TBI has been described as a disease process that can lead to an increased risk for developing chronic neurodegenerative diseases, like frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). A pathological hallmark

Traumatic brain injury (TBI) is defined as an injury to the head that disrupts normal brain function. TBI has been described as a disease process that can lead to an increased risk for developing chronic neurodegenerative diseases, like frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). A pathological hallmark of FTLD and a hallmark of ALS is the nuclear mislocalization of TAR DNA Binding Protein 43 (TDP-43). This project aims to explore neurodegenerative effects of TBI on cortical lesion area using immunohistochemical markers of TDP-43 proteinopathies. We analyzed the total percent of NEUN positive cells displaying TDP-43 nuclear mislocalization. We found that the percent of NEUN positive cells displaying TDP-43 nuclear mislocalization was significantly higher in cortical tissue following TBI when compared to the age-matched control brains. The cortical lesion area was analyzed for each injured brain sample, with respect to days post-injury (DPI), and it was found that there were no statistically significant differences between cortical lesion areas across time points. The percent of NEUN positive cells displaying TDP-43 nuclear mislocalization was analyzed for each cortical tissue sample, with respect to cortical lesion area, and it was found that there were no statistically significant differences between the percent of NEUN positive cells displaying TDP-43 nuclear mislocalization, with respect to cortical lesion area. In conclusion, we found no correlation between the percent of cortical NEUN positive cells displaying TDP-43 nuclear mislocalization with respect to the size of the cortical lesion area.

ContributorsWong, Jennifer (Author) / Stabenfeldt, Sarah (Thesis director) / Bjorklund, Reed (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2022-05