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ASU Electronic Theses and Dissertations


This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.




Neurostimulation methods currently include deep brain stimulation (DBS), optogenetic, transcranial direct-current stimulation (tDCS), and transcranial magnetic stimulation (TMS). TMS and tDCS are noninvasive techniques whereas DBS and optogenetic require surgical implantation of electrodes or light emitting devices. All approaches, except for optogenetic, have been implemented in clinical settings because they have demonstrated therapeutic utility and clinical efficacy for neurological and psychiatric disorders. When applied for therapeutic applications, these techniques suffer from limitations that hinder the progression of its intended use to treat compromised brain function. DBS requires an invasive surgical procedure that surfaces complications from infection, longevity of electrical components, …

Contributors
Tufail, Yusuf, Tyler, William J, Duch, Carsten, et al.
Created Date
2011

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 …

Contributors
Hillebrand, Peter, Kleim, Jeffrey A, Helms Tillery, Stephen I, et al.
Created Date
2019

Long-term monitoring of deep brain structures using microelectrode implants is critical for the success of emerging clinical applications including cortical neural prostheses, deep brain stimulation and other neurobiology studies such as progression of disease states, learning and memory, brain mapping etc. However, current microelectrode technologies are not capable enough of reaching those clinical milestones given their inconsistency in performance and reliability in long-term studies. In all the aforementioned applications, it is important to understand the limitations & demands posed by technology as well as biological processes. Recent advances in implantable Micro Electro Mechanical Systems (MEMS) technology have tremendous potential and …

Contributors
Palaniswamy, Sivakumar, Muthuswamy, Jitendran, Buneo, Christopher, et al.
Created Date
2016

The use of a non-invasive form of energy to modulate neural structures has gained wide spread attention because of its ability to remotely control neural excitation. This study investigates the ability of focused high frequency ultrasound to modulate the excitability the peripheral nerve of an amphibian. A 5MHz ultrasound transducer is used for the study with the pulse characteristics of 57msec long train burst and duty cycle of 8% followed by an interrogative electrical stimulus varying from 30μsecs to 2msecs in pulse duration. The nerve excitability is determined by the compound action potential (CAP) amplitude evoked by a constant electrical …

Contributors
Chirania, Sanchit, Towe, Bruce, Abbas, James, et al.
Created Date
2016

There is a critical need for creating an implantable microscale neural interface that can chronically monitor neural activity and oxygenation. These are key aspects for understating the development of impaired neural circuits and their functions. A technology with such capability would foster new insights in the studies of brain diseases and disorders. The propose is that MR-PISTOL (Proton imaging of Siloxane to Map Tissue Oxygenation Levels) imaging technique can be used for direct measurements of oxygen partial pressure at microelectrode-tissue interface. The strategy consists of coating microelectrodes with soft-silicone, a ultra-soft conductive PDMS (polydimethylsiloxane), as a carrier for liquid siloxanes …

Contributors
de Mesquita Teixeira, Livia, Muthuswamy, Jitendran, Kodibagkar, Vikram, et al.
Created Date
2018

The basal ganglia are four sub-cortical nuclei associated with motor control and reward learning. They are part of numerous larger mostly segregated loops where the basal ganglia receive inputs from specific regions of cortex. Converging on these inputs are dopaminergic neurons that alter their firing based on received and/or predicted rewarding outcomes of a behavior. The basal ganglia's output feeds through the thalamus back to the areas of the cortex where the loop originated. Understanding the dynamic interactions between the various parts of these loops is critical to understanding the basal ganglia's role in motor control and reward based learning. …

Contributors
Baldwin, Nathan A., Helms Tillery, Stephen I, Castañeda, Edward, et al.
Created Date
2014

Advances in implantable MEMS technology has made possible adaptive micro-robotic implants that can track and record from single neurons in the brain. Development of autonomous neural interfaces opens up exciting possibilities of micro-robots performing standard electrophysiological techniques that would previously take researchers several hundred hours to train and achieve the desired skill level. It would result in more reliable and adaptive neural interfaces that could record optimal neural activity 24/7 with high fidelity signals, high yield and increased throughput. The main contribution here is validating adaptive strategies to overcome challenges in autonomous navigation of microelectrodes inside the brain. The following …

Contributors
Anand, Sindhu, Muthuswamy, Jitendran, Tillery, Stephen H, et al.
Created Date
2013

A direct Magnetic Resonance (MR)-based neural activity mapping technique with high spatial and temporal resolution may accelerate studies of brain functional organization. The most widely used technique for brain functional imaging is functional Magnetic Resonance Image (fMRI). The spatial resolution of fMRI is high. However, fMRI signals are highly influenced by the vasculature in each voxel and can be affected by capillary orientation and vessel size. Functional MRI analysis may, therefore, produce misleading results when voxels are nearby large vessels. Another problem in fMRI is that hemodynamic responses are slower than the neuronal activity. Therefore, temporal resolution is limited in …

Contributors
Fu, Fanrui, Sadleir, Rosalind, Kodibagkar, Vikram, et al.
Created Date
2019