Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- All Subjects: Bilayer Metallization
- All Subjects: nerve stimulation
Description
Sleep is an essential human function. Modern day society has made it so that sleep is prioritized less and less. Professionals in critical positions such as doctors, nurses, and emergency medical technicians can often have hectic schedules that are unforgiving toward sleep due to the increase in shift work that dominates these fields. Sleep deficits can have detrimental effects on one’s psyche and mood. Depression and anxiety both have high comorbidity rates with insomnia because of sleeping deficits. Transdermal Electrical Nerve Stimulation (TENS) offers a potential solution to improving sleep quality and mood by modulating the ascending reticular activating system (RAS). This system starts in the anterior portion of the head with trigeminal nerve branches and is stimulated using a 500-550 Hz waveform.
In this experiment Positive Affect and Negative Affect Schedule (PANAS) scores are recorded daily to monitor mood differences between pre and post treatment (TENS vs Sham). PANAS scores were found to be insignificant between groups. Pittsburgh Sleep Quality Index (PSQI), and Fitbit were chosen to study perceived sleep, and objective sleep. Both PSQI, and Fitbit found insignificant differences between TENS and Sham. Finally, the Beck Depression and Beck Anxiety Inventories were administered weekly to determine if there are immediate changes to depressive and anxiety symptom, after a week of treatment (TENS vs Sham). A significant difference was found between the pre and post of the TENS treatment group. The TENS group was not found to be significantly different from Sham, potentially the result of a placebo effect. These results were found with n=10 participants in the TENS treatment group and n=6 in the sham group.
In this experiment Positive Affect and Negative Affect Schedule (PANAS) scores are recorded daily to monitor mood differences between pre and post treatment (TENS vs Sham). PANAS scores were found to be insignificant between groups. Pittsburgh Sleep Quality Index (PSQI), and Fitbit were chosen to study perceived sleep, and objective sleep. Both PSQI, and Fitbit found insignificant differences between TENS and Sham. Finally, the Beck Depression and Beck Anxiety Inventories were administered weekly to determine if there are immediate changes to depressive and anxiety symptom, after a week of treatment (TENS vs Sham). A significant difference was found between the pre and post of the TENS treatment group. The TENS group was not found to be significantly different from Sham, potentially the result of a placebo effect. These results were found with n=10 participants in the TENS treatment group and n=6 in the sham group.
ContributorsUdave, Ceasar (Author) / Tyler, William J (Thesis advisor) / Buneo, Christopher (Committee member) / Wyckoff, Sarah (Committee member) / Arizona State University (Publisher)
Created2018
Description
Neural interfacing applications have advanced in complexity, with needs for increasingly high degrees of freedom in prosthetic device control, sharper discrimination in sensory percepts in bidirectional interfaces, and more precise localization of functional connectivity in the brain. As such, there is a growing need for reliable neurophysiological recordings at a fine spatial scale matching that of cortical columnar processing. Penetrating microelectrodes provide localization sufficient to isolate action potential (AP) waveforms, but often suffer from recorded signal deterioration linked to foreign body response. Micro-Electrocorticography (μECoG) surface electrodes elicit lower foreign body response and show greater chronic stability of recorded signals, though they typically lack the signal localization necessary to isolate individual APs. This dissertation validates the recording capacity of a novel, flexible, large area μECoG array with bilayer routing in a feline implant, and explores the ability of conventional μECoG arrays to detect features of neuronal activity in a very high frequency band associated with AP waveforms.
Recordings from both layers of the flexible μECoG array showed frequency features typical of cortical local field potentials (LFP) and were shown to be stable in amplitude over time. Recordings from both layers also showed consistent, frequency-dependent modulation after induction of general anesthesia, with large increases in beta and gamma band and decreases in theta band observed over three experiments. Recordings from conventional μECoG arrays over human cortex showed robust modulation in a high frequency (250-2000 Hz) band upon production of spoken words. Modulation in this band was used to predict spoken words with over 90% accuracy. Basal Ganglia neuronal AP firing was also shown to significantly correlate with various cortical μECoG recordings in this frequency band. Results indicate that μECoG surface electrodes may detect high frequency neuronal activity potentially associated with AP firing, a source of information previously unutilized by these devices.
Recordings from both layers of the flexible μECoG array showed frequency features typical of cortical local field potentials (LFP) and were shown to be stable in amplitude over time. Recordings from both layers also showed consistent, frequency-dependent modulation after induction of general anesthesia, with large increases in beta and gamma band and decreases in theta band observed over three experiments. Recordings from conventional μECoG arrays over human cortex showed robust modulation in a high frequency (250-2000 Hz) band upon production of spoken words. Modulation in this band was used to predict spoken words with over 90% accuracy. Basal Ganglia neuronal AP firing was also shown to significantly correlate with various cortical μECoG recordings in this frequency band. Results indicate that μECoG surface electrodes may detect high frequency neuronal activity potentially associated with AP firing, a source of information previously unutilized by these devices.
ContributorsBarton, Cody David (Author) / Greger, Bradley (Thesis advisor, Committee member) / Santello, Marco (Committee member) / Buneo, Christopher (Committee member) / Graudejus, Oliver (Committee member) / Artemiadis, Panagiotis (Committee member) / Arizona State University (Publisher)
Created2018