Matching Items (924)
Description
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, and immune responses to foreign materials. Both TMS and tDCS circumvent the problems seen with DBS as they are noninvasive procedures, but they fail to produce the spatial resolution required to target specific brain structures. Realizing these restrictions, we sought out to use ultrasound as a neurostimulation modality. Ultrasound is capable of achieving greater resolution than TMS and tDCS, as we have demonstrated a ~2mm lateral resolution, which can be delivered noninvasively. These characteristics place ultrasound superior to current neurostimulation methods. For these reasons, this dissertation provides a developed protocol to use transcranial pulsed ultrasound (TPU) as a neurostimulation technique. These investigations implement electrophysiological, optophysiological, immunohistological, and behavioral methods to elucidate the effects of ultrasound on the central nervous system and raise questions about the functional consequences. Intriguingly, we showed that TPU was also capable of stimulating intact sub-cortical circuits in the anesthetized mouse. These data reveal that TPU can evoke synchronous oscillations in the hippocampus in addition to increasing expression of brain-derived neurotrophic factor (BDNF). Considering these observations, and the ability to noninvasively stimulate neuronal activity on a mesoscale resolution, reveals a potential avenue to be effective in clinical settings where current brain stimulation techniques have shown to be beneficial. Thus, the results explained by this dissertation help to pronounce the significance for these protocols to gain translational recognition.
ContributorsTufail, Yusuf Zahid (Author) / Tyler, William J (Thesis advisor) / Duch, Carsten (Committee member) / Muthuswamy, Jitendran (Committee member) / Santello, Marco (Committee member) / Tillery, Stephen H (Committee member) / Arizona State University (Publisher)
Created2011
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
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
Sensory gating is a process by which the nervous system preferentially admits stimuli that are important for the organism while filtering out those that may be meaningless. An optimal sensory gate cannot be static or inflexible, but rather plastic and informed by past experiences. Learning enables sensory gates to recognize stimuli that are emotionally salient and potentially predictive of positive or negative outcomes essential to survival. Olfaction is the only sensory modality in mammals where sensory inputs bypass conventional thalamic gating before entering higher emotional or cognitive brain regions. Thus, olfactory bulb circuits may have a heavier burden of sensory gating compared to other primary sensory circuits. How do the primary synapses in an olfactory system "learn"' in order to optimally gate or filter sensory stimuli? I hypothesize that centrifugal neuromodulator serotonin serves as a signaling mechanism by which primary olfactory circuits can experience learning informed sensory gating. To test my hypothesis, I conditioned genetically-modified mice using reward or fear olfactory-cued learning paradigms and used pharmacological, electrophysiological, immunohistochemical, and optical imaging approaches to assay changes in serotonin signaling or functional changes in primary olfactory circuits. My results indicate serotonin is a key mediator in the acquisition of olfactory fear memories through the activation of its type 2A receptors in the olfactory bulb. Functionally within the first synaptic relay of olfactory glomeruli, serotonin type 2A receptor activation decreases excitatory glutamatergic drive of olfactory sensory neurons through both presynaptic and postsynaptic mechanisms. I propose that serotonergic signaling decreases excitatory drive, thereby disconnecting olfactory sensory neurons from odor responses once information is learned and its behavioral significance is consolidated. I found that learning induced chronic changes in the density of serotonin fibers and receptors, which persisted in glomeruli encoding the conditioning odor. Such persistent changes could represent a sensory gate stabilized by memory. I hypothesize this ensures that the glomerulus encoding meaningful odors are much more sensitive to future serotonin signaling as such arousal cues arrive from centrifugal pathways originating in the dorsal raphe nucleus. The results advocate that a simple associative memory trace can be formed at primary sensory synapses to facilitate optimal sensory gating in mammalian olfaction.
ContributorsLi, Monica (Author) / Tyler, William J (Thesis advisor) / Smith, Brian H. (Thesis advisor) / Duch, Carsten (Committee member) / Neisewander, Janet (Committee member) / Vu, Eric (Committee member) / Arizona State University (Publisher)
Created2012
ContributorsHandel, George Frideric, 1685-1759 (Composer)
ContributorsHandel, George Frideric, 1685-1759 (Composer)
ContributorsHandel, George Frideric, 1685-1759 (Composer) / Halvorsen, Johan, 1864-1935 (Composer)
ContributorsHandel, George Frideric, 1685-1759 (Composer)
ContributorsHandel, George Frideric, 1685-1759 (Composer)