Matching Items (90)
Filtering by
- Genre: Masters Thesis
- Creators: Arizona State University
Description
For my graduate thesis, I present an annotated bibliography that evaluates and summarizes a list of resources available for use in future research. The resources focus on
how pectus excavatum, a congenital birth anomaly affecting the thoracic wall, may
impact identity formation and subsequent behavior during a period characterized by
significant physical and psychological development, from the ages 12 to 18, known as
adolescence. I examine resources that specifically look at congenital birth anomalies,
pectus excavatum, developmental psychology, psychoanalysis, and identity crises. The
following provides background and an annotated bibliography to establish whether there
is a causal relationship between individuals born with congenital birth anomalies,
specifically pectus excavatum (PE), and the impact it has to identity development during
adolescence. This work is important to me because I was born with pectus excavatum,
and I believe a causal relationship does exist. While I claim the causal relationship does
exist, I should note this is conjecture and anecdotally based on 7 years of interacting with
patients in both a clinical and personal setting. The conversations are reflective of
discussions that have taken place about having been born with pectus excavatum and how
the condition has impacted our lives.
ContributorsMihuc, Michael (Author) / Maienschein, Jane (Thesis advisor) / Ellison, Karin (Committee member) / Gur-Arie, Rachel (Committee member) / Arizona State University (Publisher)
Created2023
Description
The corpus callosum is a core white matter structure that sits at the center of the brain, playing a role in both interhemispheric communication and the inhibition of hemispheric activity to promote lateralization. Structural connectivity is thought to underlie functional connectivity (FC), but cases of structural brain abnormalities allow for a better understanding of this relationship. Agenesis of the corpus callosum (AgCC) is a condition in which an individual is born without a corpus callosum. These individuals provide a unique opportunity to investigate ways in which the brain adapts its functional organization to the lack of interhemispheric structural connectivity, thereby providing unique insights into brain network organization within and between the two cerebral hemispheres. The present study uses resting-state functional magnetic resonance imaging (fMRI) to compare the network connectivity of an individual with AgCC without any significant comorbidities to a control group of neurotypical adults (n=30). Potential differences of FC within the default mode network and frontoparietal network, as well as FC between these networks and bilateral language networks were examined. The AgCC individual displayed significantly higher FC within the frontoparietal network (t(29)=1.84, p<0.05) and significantly lower FC between the default mode network and the right ventral language stream (t(29)=-1.81, p<0.05) compared to the control group. Further analyses suggest that the right hemisphere’s frontoparietal network is driving the significant difference between the case study and control group in the frontoparietal network. The stronger FC of the frontoparietal network may represent a compensatory strategy used to support lower overall levels of default mode network and dual stream language network connectivity. Overall, the findings suggest that decreased interhemispheric structural connectivity may lead to increased compensation via attention networks such as the frontoparietal network, and decreased right hemisphere language network involvement.
ContributorsDungca, Lalaine Rose (Author) / Rogalsky, Corianne (Thesis advisor) / Schaefer, Sydney (Committee member) / Braden, Blair (Committee member) / Arizona State University (Publisher)
Created2023
Description
Little is known about how cognitive and brain aging patterns differ in older adults with autism spectrum disorder (ASD). However, recent evidence suggests that individuals with ASD may be at greater risk of pathological aging conditions than their neurotypical (NT) counterparts. A growing body of research indicates that older adults with ASD may experience accelerated cognitive decline and neurodegeneration as they age, although studies are limited by their cross-sectional design in a population with strong age-cohort effects. Studying aging in ASD and identifying biomarkers to predict atypical aging is important because the population of older individuals with ASD is growing. Understanding the unique challenges faced as autistic adults age is necessary to develop treatments to improve quality of life and preserve independence. In this study, a longitudinal design was used to characterize cognitive and brain aging trajectories in ASD as a function of autistic trait severity. Principal components analysis (PCA) was used to derive a cognitive metric that best explains performance variability on tasks measuring memory ability and executive function. The slope of the integrated persistent feature (SIP) was used to quantify functional connectivity; the SIP is a novel, threshold-free graph theory metric which summarizes the speed of information diffusion in the brain. Longitudinal mixed models were using to predict cognitive and brain aging trajectories (measured via the SIP) as a function of autistic trait severity, sex, and their interaction. The sensitivity of the SIP was also compared with traditional graph theory metrics. It was hypothesized that older adults with ASD would experience accelerated cognitive and brain aging and furthermore, age-related changes in brain network topology would predict age-related changes in cognitive performance.
For both cognitive and brain aging, autistic traits and sex interacted to predict trajectories, such that older men with high autistic traits were most at risk for poorer outcomes. In men with autism, variability in SIP scores across time points trended toward predicting cognitive aging trajectories. Findings also suggested that autistic traits are more sensitive to differences in brain aging than diagnostic group and that the SIP is more sensitive to brain aging trajectories than other graph theory metrics. However, further research is required to determine how physiological biomarkers such as the SIP are associated with cognitive outcomes.
ContributorsSullivan, Georgia (Author) / Braden, Blair (Thesis advisor) / Kodibagkar, Vikram (Thesis advisor) / Schaefer, Sydney (Committee member) / Wang, Yalin (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis explores the interplay of aphasia symptoms and brain connectivityusing resting-state functional Magnetic Resonance Imaging (MRI). The research presented here is a step towards understanding the neural basis of linguistic prosody in particular, and its relationship with language impairments in post-stroke aphasia. This study focuses on examining the functional connectivities of the frontal-parietal control network and the dorsal attention networks with specific regions within traditional language networks, as a growing body of research suggests that prosodic cues in speech may recruit control and attention networks to support language processing. Using resting- state fMRI, the present study examined the functional connectivity of the frontal parietal control and dorsal attention networks with traditional language regions in 28 participants who have experienced a stroke-related language impairment (i.e. aphasia) and 32 matched neurotypical adults. Overall, the study reveals significant functional connectivity differences of the frontoparietal control and dorsal attention networks between the stroke and control groups, indicating that individuals with aphasia have brain connectivity differences beyond the traditional language networks. Multiple regression analyses were then used to determine if functional connectivities of the frontoparietal control and dorsal attention networks within themselves and with traditional language regions could predict aphasia symptoms, as measured by the Western Aphasia Battery (WAB). Overall, the regression results indicate that greater functional connectivity between the frontoparietal control and dorsal attention networks with traditional language regions is associated with improved language abilities, with different connectivities predicting different types of aphasia symptoms (e.g. speech, naming / word finding, auditory comprehension, overall impairment). Altogether this study contributes to the understanding of the neural bases of language impairments post-stroke, highlighting the intricate connections between language and other cognitive networks, which may be mediated by prosody.
ContributorsMendhe, Surbhi Haridas (Author) / Rogalsky, Corianne (Thesis advisor) / Braden, B. Blair (Committee member) / Benitez, Viridiana (Committee member) / Arizona State University (Publisher)
Created2024
Description
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the deterioration of both upper and lower motor neurons in the brain, brain stem, and spinal cord. Multiple missense mutations have been connected to ALS, including mutations in the Matr3 gene. Matrin-3 is an RNA and DNA-binding protein encoded by the Matr3 gene. Normally found in the nuclear matrix, Matrin-3 plays several roles vital to RNA metabolism, including splicing, mRNA transport, mRNA stability, and transcription. The most common Matr3 mutation identified in familial ALS (fALS) patients is the S85C mutation, but the mechanisms through which it contributes to ALS pathology remain unknown. This makes mouse models particularly useful in elucidating pathological mechanisms, having the potential to serve as preclinical models for therapeutic drugs. For this thesis project, an ALS mouse model for the Matr3 S85C mutation was created, specifically generating a CRISPR/Cas9 mediated knock-in mouse model containing the Matr3 S85C mutation expressed under the control of the endogenous promoter. The Matr3S85C/S85C mice displayed significant phenotypic differences, such as reduced size, impaired motor coordination, and shortening of lifespan. Moreover, the Matr3S85C/S85C mice exhibited ALS-like pathology in both the muscle and central nervous system (CNS). Muscle pathology included decreased muscle fiber size and Matrin-3 loss. CNS pathology included selective neurodegeneration, Matrin-3 loss, neuroinflammation, and reduction of N6-methyladenosine (m6A) RNA modifications. Bulk RNA sequencing (RNA-seq) revealed significant differential gene expression in the Matr3S85C/S85C mice compared to Matr3+/+ mice, with synaptic pathways being particularly affected. Overall, the Matr3 S85C mutation induced both phenotypic effects and ALS-like pathology in vivo.
ContributorsHouchins, Nicole (Author) / Medina, David (Thesis advisor) / Velazquez, Ramon (Thesis advisor) / Tseng, Jui-Heng (Committee member) / Arizona State University (Publisher)
Created2024
Description
Vagus nerve stimulation (VNS) has shown benefits beyond its original therapeutic application, though there is a lack of research into these benefits in healthy and athletic populations. To address this gap in the VNS literature, the present study addresses the feasibility and possible efficacy of transcutaneous VNS (tVNS) in improving performance and various biometrics during two athletic tasks: golf tee shots and baseball pitching. Performance, cortical dynamics, anxiety measures, muscle excitation, and heart rate characteristics were assessed before and after stimulation using electroencephalography (EEG), the State-Trait Anxiety Inventory (STAI), and electrocardiography (ECG) during the baseball and golf tasks as well as electromyography (EMG) for muscle excitation in the golf participants. Golfers exhibited increased perceived quality of each repetition (independent from outcome) and an improvement in state and trait anxiety after stimulation. Golfers in the active stimulation group also showed a greater reduction in right upper trapezius muscle excitation when compared to the sham stimulation group. Baseball pitchers exhibited an increase in perceived quality of each repetition (independent from outcome) after active stimulation but not an improvement of state and trait anxiety. No significant effects of stimulation Priming, stimulation Type, or the Priming×Type interaction were seen in heart rate, EEG, or performance in the golf or baseball tasks. The present study supports the feasibility of tVNS in sports and athletic tasks and suggests the need for future research to investigate further into the effects of tVNS on the performance, psychologic, and physiologic attributes of athletes during competition.
ContributorsLindley, Kyle (Author) / Tyler, William J (Thesis advisor) / Wyckoff, Sarah (Committee member) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2019
Description
Every year, 3 million older people are treated for fall injuries, and nearly 800,000 are hospitalized, many of which due to head injuries or hip fractures. In 2015 alone, Medicare and Medicaid paid nearly 75% of the $50 Billion in medical costs generated by falls. As the US population continues to age, more adults are beginning to deal with movement related disorders, and the need to be able to detect and mitigate these risks is becoming more necessary. Classical metrics of fall risk can capture static stability, but recent advancements have yielded new metrics to analyze balance and stability during movement, such as the Maximum Lyapunov Exponent (MLE). Much work has been devoted to characterizing gait, but little has explored novel way to reduce fall risk with interventional therapy. Targeting certain cranial nerves using electrical stimulation has shown potential for treatment of movement disorders such as Parkinson’s Disease (PD) in certain animal models. For human models, based on ease of access, connection to afferents leading to the lower lumber region and key brain regions, as well as general parasympathetic response, targeting the cervical nerves may have a more significant effect on balance and posture. This project explored the effects of transcutaneous Cervical Nerve Stimulation (CNS) on posture stability and gait with the practical application of ultimately applying this treatment to fall risk populations. Data was collected on each of the 31 healthy adults (22.3 ± 6.3 yrs) both pre and post stimulation for metrics representative of fall risk such as postural stability both eyes open and closed, Timed-Up-and-Go (TUG) time, gait velocity, and MLE. Significant differences manifested in the postural stability sub-metric of sway area with subject eyes open in the active stimulation group. The additional 8 metrics and sub-metrics did not show statistically significant differences among the active or sham groups. It is reasonable to conclude that transcutaneous CNS does not significantly affect fall risk metrics in healthy adults. This can potentially be attributed to either the stimulation method chosen, internal brain control mechanisms of posture and balance, analysis methods, and the Yerkes-Dodson law of optimal arousal. However, no adverse events were reported in the active group and thus is a safe therapy option for future experimentation.
ContributorsKreisler, Itai Goeta (Author) / Lockhart, Thurmon E (Thesis advisor) / Tyler, William J (Thesis advisor) / Wyckoff, Sarah (Committee member) / Arizona State University (Publisher)
Created2019
Description
Vagal Nerve Stimulation (VNS) has been shown to be a promising therapeutic technique in treating many neurological diseases, including epilepsy, stroke, traumatic brain injury, and migraine headache. The mechanisms by which VNS acts, however, are not fully understood but may involve changes in cerebral blood flow. The vagus nerve plays a significant role in the regulation of heart rate and cerebral blood flow that are altered during VNS. Here, the effects of acute vagal nerve stimulation using varying stimulation parameters on both heart rate and cerebral blood flow were examined. Laser Speckle Contrast Analysis (LASCA) was used to analyze the cerebral blood flow of male Long–Evans rats. In the first experiment, results showed two distinct patterns of responses to 0.8mA of stimulation whereby animals either experienced a mild or severe decrease in heart rate. Further, animals that displayed mild heart rate decreases showed an increase in cerebral blood flow that persisted beyond VNS. Animals that displayed severe decreases showed a transient decrease in cerebral blood flow followed by an increase that was greater than that observed in mild animals but progressively decreased after VNS. The results suggest two distinct patterns of changes in both heart rate and blood flow that may be related to the intensity of VNS. To investigate the effects of lower levels of stimulation, an additional group of animals were stimulated at 0.4mA. The results showed moderate changes in heart rate but no significant changes in cerebral blood flow in these animals. The results demonstrate that VNS alters both heart rate and cerebral blood flow and that these effects are dependent on current intensity.
ContributorsHillebrand, Peter (M.S.) (Author) / Kleim, Jeffrey A (Thesis advisor) / Helms Tillery, Stephen I (Committee member) / Muthuswamy, Jitendran (Committee member) / Arizona State University (Publisher)
Created2019
Description
With a growing number of adults with autism spectrum disorder (ASD), more and more research has been conducted on majority male cohorts with ASD from young, adolescence, and some older age. Currently, males make up the majority of individuals diagnosed with ASD, however, recent research states that the gender gap is closing due to more advanced screening and a better understanding of how females with ASD present their symptoms. Little research has been published on the neurocognitive differences that exist between older adults with ASD compared to neurotypical (NT) counterparts, and nothing has specifically addressed older women with ASD. This study utilized neuroimaging and neuropsychological tests to examine differences between diagnosis and sex of four distinct groups: older men with ASD, older women with ASD, older NT men, and older NT women. In each group, hippocampal size (via FreeSurfer) was analyzed for differences as well as correlations with neuropsychological tests. Participants (ASD Female, n = 12; NT Female, n = 14; ASD Male, n = 30; NT Male = 22), were similar according to age, IQ, and education. The results of the study indicated that the ASD Group as a whole performed worse on executive functioning tasks (Wisconsin Card Sorting Test, Trails Making Test) and memory-related tasks (Rey Auditory Verbal Learning Test, Weschler Memory Scale: Visual Reproduction) compared to the NT Group. Interactions of sex by diagnosis approached significance only within the WCST non-perseverative errors, with the women with ASD performing worse than NT women, but no group differences between men. Effect sizes between the female groups (ASD female vs. NT female) showed more than double that of the male groups (ASD male vs. NT male) for all WCST and AVLT measures. Participants with ASD had significantly smaller right hippocampal volumes than NT participants. In addition, all older women showed larger hippocampal volumes when corrected for total intracranial volume (TIV) compared to all older men. Overall, NT Females had significant correlations across all neuropsychological tests and their hippocampal volumes whereas no other group had significant correlations. These results suggest a tighter coupling between hippocampal size and cognition in NT Females than NT Males and both sexes with ASD. This study promotes further understanding of the neuropsychological differences between older men and women, both with and without ASD. Further research is needed on a larger sample of older women with and without ASD.
ContributorsWebb, Christen Len (Author) / Braden, B. Blair (Thesis advisor) / Azuma, Tamiko (Committee member) / Dixon, Maria (Committee member) / Arizona State University (Publisher)
Created2019
Description
Properly deciding to engage in or to withhold an action is a critical ability for goal-oriented movement control. Such decision may be driven by expected value from the choice of action but associating physical effort may discount such value. A novel anticipatory stopping task was developed to investigate effort discounted decision process potentially present in proactive inhibitory control. Subjects performed or abstained from target reach if they believed it was a Go or Stop trial respectively. Reward was awarded to a reach, correctly timed to hit a target at the same time as the moving bar in Go trials. During the Stop trials, correctly judging to not engage in a reach from the color of the moving bar that linked to the bar’s probability of stopping before the target resulted in gaining a reward. Resistive force field incurred additional physical effort for choosing to reach. Introducing effort expectedly decreased the tendency to respond at trials with higher stop probability. Surprisingly, tendency to respond increased and corresponding reaction time decreased in the trials with lower stop probability. Such asymmetric effect suggests that the value of context ineffective response is discounted, and the value of context effective response is flexibly enhanced by its associated effort cost to drive decision-process in goal-oriented manner. Medial frontal event related potential (ERP) locked to the onset of moving bar appearance reflected such effort discounted decision process. Theta band observed in Stop trials accounted for evaluation of effort and context possibly reinforcing such decision-making.
ContributorsTsuchiya, Toshiki (Author) / Santello, Marco (Thesis advisor) / Fine, Justin (Committee member) / McClure, Samuel (Committee member) / Arizona State University (Publisher)
Created2018