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Somatosensory Modulation during Speech Planning

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Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel…

Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel out the resulting sensory feedback. Currently, there are no published accounts of the perception of tactile signals for motor tasks and contexts related to the lips during both speech planning and production. In this study, we measured the responsiveness of the somatosensory system during speech planning using light electrical stimulation below the lower lip by comparing perception during mixed speaking and silent reading conditions. Participants were asked to judge whether a constant near-threshold electrical stimulation (subject-specific intensity, 85% detected at rest) was present during different time points relative to an initial visual cue. In the speaking condition, participants overtly produced target words shown on a computer monitor. In the reading condition, participants read the same target words silently to themselves without any movement or sound. We found that detection of the stimulus was attenuated during speaking conditions while remaining at a constant level close to the perceptual threshold throughout the silent reading condition. Perceptual modulation was most intense during speech production and showed some attenuation just prior to speech production during the planning period of speech. This demonstrates that there is a significant decrease in the responsiveness of the somatosensory system during speech production as well as milliseconds before speech is even produced which has implications for speech disorders such as stuttering and schizophrenia with pronounced deficits in the somatosensory system.
ContributorsMcguffin, Brianna Jean (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Startle-evoked movement in multi-jointed, two-dimensional reaching tasks

Description
Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown that SEM enhances single joint movements that are usually performed…

Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown that SEM enhances single joint movements that are usually performed with difficulty. While the presence of SEM in the stroke survivor population advances scientific understanding of movement capabilities following a stroke, published studies using the SEM phenomenon only examined one joint. The ability of SEM to generate multi-jointed movements is understudied and consequently limits SEM as a potential therapy tool. In order to apply SEM as a therapy tool however, the biomechanics of the arm in multi-jointed movement planning and execution must be better understood. Thus, the objective of our study was to evaluate if SEM could elicit multi-joint reaching movements that were accurate in an unrestrained, two-dimensional workspace. Data was collected from ten subjects with no previous neck, arm, or brain injury. Each subject performed a reaching task to five Targets that were equally spaced in a semi-circle to create a two-dimensional workspace. The subject reached to each Target following a sequence of two non-startling acoustic stimuli cues: "Get Ready" and "Go". A loud acoustic stimuli was randomly substituted for the "Go" cue. We hypothesized that SEM is accessible and accurate for unrestricted multi-jointed reaching tasks in a functional workspace and is therefore independent of movement direction. Our results found that SEM is possible in all five Target directions. The probability of evoking SEM and the movement kinematics (i.e. total movement time, linear deviation, average velocity) to each Target are not statistically different. Thus, we conclude that SEM is possible in a functional workspace and is not dependent on where arm stability is maximized. Moreover, coordinated preparation and storage of a multi-jointed movement is indeed possible.
ContributorsOssanna, Meilin Ryan (Author) / Honeycutt, Claire (Thesis director) / Schaefer, Sydney (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Comparing Protocols for Extracting, Amplifying, and Imaging ApoE ε4 Allele: Preliminary work for understanding Alzheimer’s Disease in asymptomatic individuals

Description
This thesis aimed to develop a consistent protocol used to effectively image the apolipoprotein E (ApoE) ε4 allele, which is a known genetic risk factor for Alzheimer’s Disease (AD). The research team used methods to extract DNA from saliva samples, amplify the DNA using polymerase chain reaction (PCR), and image…

This thesis aimed to develop a consistent protocol used to effectively image the apolipoprotein E (ApoE) ε4 allele, which is a known genetic risk factor for Alzheimer’s Disease (AD). The research team used methods to extract DNA from saliva samples, amplify the DNA using polymerase chain reaction (PCR), and image the results using gel electrophoresis and a transilluminator. Extensive literature review was used to optimize these techniques. Future studies will use these methods of characterizing the ApoE ε4 allele as preliminary work towards the goal of integrating this protocol into ongoing research in aging within the Motor Rehabilitation and Learning (MRL) Lab on Arizona State University’s campus.
ContributorsWorman, Drew (Author) / Schaefer, Sydney (Thesis director) / Lewis, Candace (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05

DTI indices on Frontotemporal Dementia & Alzheimer’s Disease

Description

Alzheimer’s disease (AD) and Frontotemporal lobe dementia (FTLD) are types of dementia that have distinct differences. To help identify some of the neural differences, researchers use diffusion tensor imaging (DTI) techniques to assist with diagnosing patients and track progression over time. The major objective of this experiment was to use…

Alzheimer’s disease (AD) and Frontotemporal lobe dementia (FTLD) are types of dementia that have distinct differences. To help identify some of the neural differences, researchers use diffusion tensor imaging (DTI) techniques to assist with diagnosing patients and track progression over time. The major objective of this experiment was to use the advanced diffusion tensor imaging techniques of Fractional Anisotropy (FA) and Free water (FW) to help differentiate between AD and FTLD neurodegeneration. The scope of this experiment was to examine literature research on AD and FTLD by gathering the mean values of (FA) and (FW) to identify diffusivity susceptibility in the specific brain regions of the Uncinate Fasciculus (UF) and the Superior Temporal Gyrus (STG). The methods used were the Alzheimer’s Disease Neuroimaging Initiative (ADNI) and the Frontotemporal Lobe Degenerative Neuroimaging Initiative (FTLD): These data repositories provide researchers with study data to define the progression of AD and FTLD. Next, an imaging analysis was used to calculate the average FA and FW through each slice of the brain regions UF and STG in standard space. Then FreeSurfer segmented Superior Temporal Gyrus and the JHU ICBM Atlas of the Uncinate Fasciculus were used as a set of tools for analysis and visualization of structural and functional brain imaging data for processing the cross-sectional and longitudinal data. We calculated 95% Confidence intervals for mean FW and FA at each slice and direction across 21 participants within each dementia group to determine regions of overlap and nonoverlap. Results indicated that for the FA and FW graphs in the x and z directions among UF and STG regions, there were more non-overlap regions between the AD and FTLD in the FW graphs across x and z-directions in particular the UF. Our results indicate that there may be concomitant decline in white and gray matter regions in dementia, and FW may be more sensitive detecting AD related neurodegeneration in the UF and STG regions.
ContributorsMalone, Joshua (Author) / Ofori, Edward (Thesis director) / Schaefer, Sydney (Committee member) / Barrett, The Honors College (Contributor) / College of Health Solutions (Contributor)
Created2022-05
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Towards Very Early Interrogation of Neurodegenerative Diseases with Diffusion MRI

Description
It is hypothesized that changes in brain tissue microstructure, particularly degradation of neurites (i.e,. axons and dendrites) and synapses, are early drivers of Alzheimer's disease (AD) pathogenesis. Quantitative magnetic resonance imaging (MRI) tools like diffusion tensor imaging (DTI) have long been used to study AD pathogenesis. Using DTI metrics, structural…

It is hypothesized that changes in brain tissue microstructure, particularly degradation of neurites (i.e,. axons and dendrites) and synapses, are early drivers of Alzheimer's disease (AD) pathogenesis. Quantitative magnetic resonance imaging (MRI) tools like diffusion tensor imaging (DTI) have long been used to study AD pathogenesis. Using DTI metrics, structural insights of neuro tissue can be inferred but not directly measured. DTI has proven to be an effective tool indicating fractional anisotrophy (FA) differences between groups of varying AD risk factor, but it does not explicitly quantify pathophysiologically-relevant features like neurite density and complexity. This study aims to develop and validate an advanced diffusion MRI acquisition and biophysical modeling platform that can be used to explicitly quantify changes to brain tissue microstructure, specifically neurite density and complexity. Ultimately, this platform will be used to study the pathogenic mechanisms that drive AD in the pre-clinical and clinical setting.
ContributorsYamada, Nelson Garr (Author) / Beeman, Scott (Thesis advisor) / Schaefer, Sydney (Committee member) / Su, Yi (Committee member) / Arizona State University (Publisher)
Created2023