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Full-Text Articles in Medicine and Health Sciences

Eaat4-Dependent Effects On Glutamatergic Signaling In The Cerebellar Molecular Layer, Christopher Chen Apr 2024

Eaat4-Dependent Effects On Glutamatergic Signaling In The Cerebellar Molecular Layer, Christopher Chen

Dissertations (1934 -)

Glutamatergic signaling is fundamental to human behavior and its dysfunction is implicated in a wide range of neurological and neurodegenerative disorders. Excitatory amino-acid transporters (EAATs) – of which four primary subtypes (EAAT1, EAAT2, EAAT3, and EAAT4) exist in the human brain – are primary regulators of glutamate signaling. Endogenously-expressed at either low (EAAT4-low) or high (EAAT4-high) concentration in cerebellar Purkinje cells, EAAT4 has been shown to regulate Purkinje cell activity in the cerebellar molecular layer. However, differences in glutamatergic signaling at the circuit and single-synaptic levels in EAAT4-low and EAAT4-high regions are poorly understood. To characterize EAAT4-specific effects on excitatory …


Eaat4-Dependent Effects On Glutamatergic Signaling In The Cerebellar Molecular Layer, Christopher Chen Apr 2024

Eaat4-Dependent Effects On Glutamatergic Signaling In The Cerebellar Molecular Layer, Christopher Chen

Dissertations (1934 -)

Glutamatergic signaling is fundamental to human behavior and its dysfunction is implicated in a wide range of neurological and neurodegenerative disorders. Excitatory amino-acid transporters (EAATs) – of which four primary subtypes (EAAT1, EAAT2, EAAT3, and EAAT4) exist in the human brain – are primary regulators of glutamate signaling. Endogenously-expressed at either low (EAAT4-low) or high (EAAT4-high) concentration in cerebellar Purkinje cells, EAAT4 has been shown to regulate Purkinje cell activity in the cerebellar molecular layer. However, differences in glutamatergic signaling at the circuit and single-synaptic levels in EAAT4-low and EAAT4-high regions are poorly understood. To characterize EAAT4-specific effects on excitatory …


The Neural Encoding Of Reward In The Striatal-Pallidal Circuitry, Chung Lung Chan Jul 2017

The Neural Encoding Of Reward In The Striatal-Pallidal Circuitry, Chung Lung Chan

Dissertations (1934 -)

Humans and animals are constantly exposed to external stimuli. The ability to process reward value of a stimulus is critical to guiding appropriate behavior and essential for survival. These processes are regulated by neuronal activity and neurochemical signaling in the reward circuitry, particularly in the nucleus accumbens (NAc). The NAc receives dopaminergic inputs from the midbrain ventral tegmental area (VTA) and sends GABAergic projections to the ventral pallidum (VP). Electrophysiological studies have characterized phasic neuronal responses in the NAc that differential encode appetitive and aversive taste stimuli. Exposure to an appetitive taste stimulus evoked predominantly phasic inhibitory responses in the …


Aging, Executive Function, Fronto-Parietal Network Cortical Thickness: Insights From Cognitive Reserve, Katherine Reiter Jul 2017

Aging, Executive Function, Fronto-Parietal Network Cortical Thickness: Insights From Cognitive Reserve, Katherine Reiter

Dissertations (1934 -)

Cognitive reserve (CR) indexes the nonlinear relationship between neurological insult and behavioral change. CR is manifested in both static factors (e.g., childhood environment, education) and modifiable lifestyle factors, (e.g., leisure activities). Detailed investigation of the influence of CR on cortical thickness, which indexes neuropathology, and cognitive functioning could be particularly important in understanding the heterogeneity of Alzheimer’s disease (AD). While memory decline is the hallmark of AD, executive functioning (EF) decline often predates memory changes, making EF an important target for investigating CR influences. The current study examines the relationship of CR and genetic risk for AD (ε4) on EF …


Markerless Kinematics Of Pediatric Manual Wheelchair Mobility, Jacob Robert Rammer Jul 2017

Markerless Kinematics Of Pediatric Manual Wheelchair Mobility, Jacob Robert Rammer

Dissertations (1934 -)

Pediatric manual wheelchair users face substantial risk of orthopaedic injury to the upper extremities, particularly the shoulders, during transition to wheelchair use and during growth and development. Propulsion strategy can influence mobility efficiency, activity participation, and quality of life. The current forefront of wheelchair biomechanics research includes translating findings from adult to pediatric populations, improving the quality and efficiency of care under constrained clinical funding, and understanding injury mechanisms and risk factors. Typically, clinicians evaluate wheelchair mobility using marker-based motion capture and instrumentation systems that are precise and accurate but also time-consuming, inconvenient, and expensive for repeated assessments. There is …


Neuromuscular Function In Women Postpartum, Rita Deering Jul 2017

Neuromuscular Function In Women Postpartum, Rita Deering

Dissertations (1934 -)

Efficient abdominal muscle function is important for functional mobility in men and women, and dysfunction of these muscles has been associated with impaired function such as low back pain. This dissertation explored abdominal muscle function in healthy young men and young women who have never been pregnant (nulligravid). As pregnancy and child birth also impact the tissues of the abdominal wall, this dissertation will also explore abdominal muscle function in postpartum women. This dissertation involved three primary aims. Aim1 compared abdominal muscle function and experimental pain perception in males and nulligravid females. Maximal strength over a range of trunk angles, …


Regulation Of System Xc-By The Neuropeptide Pacap: Implications For Glutamate Transmission In Drug Addiction, Linghai Kong Apr 2017

Regulation Of System Xc-By The Neuropeptide Pacap: Implications For Glutamate Transmission In Drug Addiction, Linghai Kong

Dissertations (1934 -)

Drug addiction is a chronic brain disorder characterized by heightened relapse susceptibility. Drug-induced aberrant glutamate signaling in corticostriatal circuitry contributes to behaviors in virtually every preclinical model of drug seeking and correlates with drug craving in human. Here, we propose that glutamate signaling is a product of integrated activity between neurons and astrocytes, such that disruptions within astrocytes can stem from abnormal neuronal signaling (e.g., altered corticostriatal firing) and be the source of additional disruptions in other neuronal circuits. The astrocytic mechanism studied in these experiments is system xc- (Sxc) since drug-induced changes to this non-vesicular glutamate release mechanism contribute …


The Relationship Of Spasticity And Impairments In Force Regulation And Neuromuscular Fatigue Post Stroke, Reivian Berrios Barillas Oct 2015

The Relationship Of Spasticity And Impairments In Force Regulation And Neuromuscular Fatigue Post Stroke, Reivian Berrios Barillas

Dissertations (1934 -)

Hyperreflexia that causes muscle spasticity may contribute to limitations in force regulation and walking ability post stroke. Additionally, neuromuscular fatigue may reduce force regulation, which is important because fatigue can assist to strengthen muscles that control walking. Hyperreflexia may be caused by cortical disinhibition that allows Ia afferents to amplify excitatory synaptic inputs to motoneuron pools. Cortical disinhibition is presumably caused by stroke-related motor cortex damage. Although, other excitatory synaptic sources to motoneurons contribute to motor control, hyperreflexia may be one contributor that affects stroke survivors. However, hyperreflexia is reported infrequently to effect force regulation post stroke. The goal was …


A Neurobiological Pathway That Mediates Stress-Induced Drug Use, Oliver Vranjkovic Oct 2015

A Neurobiological Pathway That Mediates Stress-Induced Drug Use, Oliver Vranjkovic

Dissertations (1934 -)

Cocaine addiction represents a tremendous health and financial burden on our society and the high rate of relapse to cocaine use in abstinent addicts represents a major barrier to effective therapy. Thus, understanding the factors that contribute to relapse and the underlying neurobiological processes is important for guiding the development of treatment for addiction. Stressful life events often trigger drug use in recovering addicts. The contribution of stress to drug use is problematic due to the unpredictable and often uncontrollable nature of stress. A growing literature indicates that norepinephrine and corticotropin releasing factor (CRF) in the brain play key roles …


Neural Plasticity In Response To Intervention In Adolescents With Autism Spectrum Disorders, Sheryl Jayne Stevens Jul 2015

Neural Plasticity In Response To Intervention In Adolescents With Autism Spectrum Disorders, Sheryl Jayne Stevens

Dissertations (1934 -)

Current theories of Autism Spectrum Disorders (ASD) suggest that they may develop from the transactional interaction between biological risk factors and environmental processes (Dawson et al., 2009). Due to the brain’s experience-expectant nature, one’s degree of social exposure may have a significant impact on their brain development and behavioral presentation. In addition to the primary critical neurodevelopmental period identified in early childhood, recent research has demonstrated a second period of substantial neurodevelopment during the adolescent period (Sisk & Foster, 2004). This study investigated the neural and behavioral impact of participation in an empirically validated behavioral intervention (The Program for the …


Investigation Of Spatio-Temporal Effects Of Fmri Visual Field Mapping Techniques On V1, John J. Janik Oct 2011

Investigation Of Spatio-Temporal Effects Of Fmri Visual Field Mapping Techniques On V1, John J. Janik

Dissertations (1934 -)

Blood oxygenation level dependent functional magnetic resonance imaging has been used extensively for mapping the representation of the visual field within the human brain. Visual field mapping using fMRI has been used clinically to assess patients with cortical pathology and to plan surgical treatment impacting the visual system. The accuracy of fMRI-based visual field mapping methods needs to be better understood for clinical use. This accuracy can be important for presurgical mapping of brain function near a tumor resection site since inaccurate rendition of the underlying neural function could lead to inappropriate resection of viable brain tissue. The most widely …