In both areas, individual neurons were classified based on the spectrum of their spiking patterns. A large proportion of cells in the SPL that exhibited sensory condition-specific oscillatory spiking in the beta (13-30Hz) frequency band. Cells in the IPL typically had a more diverse mix of oscillatory and refractory spiking patterns during the task in response to changing sensory condition. Contrary to the assumptions made in many modelling studies, none of the cells exhibited Poisson-spiking statistics in SPL or IPL.
Evoked LFPs in both areas exhibited greater effects of target location than visual condition, though the evoked responses in the preferred reach direction were generally suppressed in the bimodal condition relative to the unimodal condition. Significant effects of target location on evoked responses were observed during the movement period of the task well.
In the frequency domain, LFP power in both cortical areas was enhanced in the beta band during the position estimation epoch of the task, indicating that LFP beta oscillations may be important for maintaining the ongoing state. This was particularly evident at the population level, with clear increase in alpha and beta power. Differences in spectral power between conditions also became apparent at the population level, with power during bimodal trials being suppressed relative to unimodal. The spike-field coherence showed confounding results in both the SPL and IPL, with no clear correlation between incidence of beta oscillations and significant beta coherence.
The scale at which non-penetrating electrode arrays can interface with cortex is evaluated in the context of extracting useful information. Articulate movements were decoded from surface microelectrode electrodes, and additional spatial analysis revealed unique signal content despite dense electrode spacing. With a basis for data extraction established, the focus shifts towards the information encoding half of neural interfaces. Finite element modeling was used to compare tissue recruitment under surface stimulation across electrode scales. Results indicated charge density-based metrics provide a reasonable approximation for current levels required to evoke a visual sensation and showed tissue recruitment increases exponentially with electrode diameter. Micro-scale electrodes (0.1 – 0.3 mm diameter) could sufficiently activate layers II/III in a model tuned to striate cortex while maintaining focal radii of activated tissue.
In vivo testing proceeded in a nonhuman primate model. Stimulation consistently evoked visual percepts at safe current thresholds. Tracking perception thresholds across one year reflected stable values within minimal fluctuation. Modulating waveform parameters was found useful in reducing charge requirements to evoke perception. Pulse frequency and phase asymmetry were each used to reduce thresholds, improve charge efficiency, lower charge per phase – charge density metrics associated with tissue damage. No impairments to photic perception were observed during the course of the study, suggesting limited tissue damage from array implantation or electrically induced neurotoxicity. The subject consistently identified stimulation on closely spaced electrodes (2 mm center-to-center) as separate percepts, indicating sub-visual degree discrete resolution may be feasible with this platform. Although continued testing is necessary, preliminary results supports epicortical microelectrode arrays as a stable platform for interfacing with neural tissue and a viable option for bi-directional BCI applications.
The effect of neuromodulation on proprioceptive sensitivity was assessed using transcutaneous electrical nerve stimulation (TENS), which has been shown to have beneficial effects on human cognitive and sensorimotor performance in other contexts. In this pilot study the effects of two frequencies (30hz and 300hz) and three electrode configurations were examined. No effect of electrode configuration was found, however sensitivity with 30hz stimulation was significantly lower than with 300hz stimulation (which was similar to sensitivity without stimulation). Although TENS was shown to modulate proprioceptive sensitivity, additional experiments are required to determine if TENS can produce enhancement rather than depression of sensitivity which would have positive implications for rehabilitation of proprioceptive deficits arising from stroke and other disorders.
Methods such as vibratory sensory substitution have shown promise for providing prosthesis users with a sense of contact and have proved helpful in completing motor tasks. In this thesis, two experiments were conducted to determine whether vibratory cues could be useful in discriminating between sizes. In the first experiment, subjects were asked to grasp a series of hidden virtual blocks of varying sizes with vibrations on the fingertips as indication of contact and compare the size of consecutive boxes. Vibratory haptic feedback significantly increased the accuracy of size discrimination over objects with only visual indication of contact, though accuracy was not as great as for typical grasping tasks with physical blocks. In the second, subjects were asked to adjust their virtual finger position around a series of virtual boxes with vibratory feedback on the fingertips using either finger movement or EMG. It was found that EMG control allowed for significantly less accuracy in size discrimination, implying that, while proprioceptive feedback alone is not enough to determine size, direct kinesthetic information about finger position is still needed.
The ongoing Global Coronavirus Pandemic has been upheaving social norms for over a<br/>year at this point. For countless people, our lives look very different at this point in time<br/>then they did before the pandemic began. Quarantine, Shelter in Place, Work from<br/>Home, and Online classes have led global populations to become less active leading to<br/>an increase in sedentary lifestyles. The final impact of this consequence is unknown,<br/>but emerging studies have led to concrete evidence of decreased physical and mental<br/>wellbeing, particularly in children. VirusFreeSports was the brainchild of three ASU<br/>Honors students who sought to remedy these devastating consequences by creating<br/>environments where children can participate in sports and exercise safely, free of the<br/>threat COVID-19 or other transmissible illnesses. The ultimate goal for the project team<br/>was to build traction for their idea, which culminated in a video pitch sent to potential<br/>investors. Although largely created as an exercise and we did not create a full<br/>certification course, merely a prototype through a website with sample questions to<br/>gauge interest, the project was a success as a large target market for this product was<br/>identified that showed great promise. Our team believes that early entrance to the<br/>market, as well as the lack of any other competitors would give the team a tremendous<br/>advantage in creating an impactful and influential service.
The ongoing Global Coronavirus Pandemic has been upheaving social norms for over a<br/>year at this point. For countless people, our lives look very different at this point in time<br/>then they did before the pandemic began. Quarantine, Shelter in Place, Work from<br/>Home, and Online classes have led global populations to become less active leading to<br/>an increase in sedentary lifestyles. The final impact of this consequence is unknown,<br/>but emerging studies have led to concrete evidence of decreased physical and mental<br/>wellbeing, particularly in children. VirusFreeSports was the brainchild of three ASU<br/>Honors students who sought to remedy these devastating consequences by creating<br/>environments where children can participate in sports and exercise safely, free of the<br/>threat COVID-19 or other transmissible illnesses. The ultimate goal for the project team<br/>was to build traction for their idea, which culminated in a video pitch sent to potential<br/>investors. Although largely created as an exercise and we did not create a full<br/>certification course, merely a prototype through a website with sample questions to<br/>gauge interest, the project was a success as a large target market for this product was<br/>identified that showed great promise. Our team believes that early entrance to the<br/>market, as well as the lack of any other competitors would give the team a tremendous<br/>advantage in creating an impactful and influential service.
The ongoing Global Coronavirus Pandemic has been upheving social norms for over a year at this point. For countless people, our lives look very different at this point in time than they did before the pandemic began. Quarantine, Shelter in Place, Work from Home, and Online classes have led global populations to become less active leading to an increase in sedentary lifestyles. The final impact of this consequence is unknown, but emerging studies have led to concrete evidence of decreased physical and mental wellbeing, particularly in children. VirusFreeSports was the brainchild of three ASU Honors students who sought to remedy these devastating consequences by creating environments where children can participate in sports and exercise safely, free of the threat COVID-19 or other transmissible illnesses. The ultimate goal for the project team was to build traction for their idea, which culminated in a video pitch sent to potential investors. Although largely created as an exercise and we did not create a full certification course, merely a prototype through a website with sample questions to gauge interest, the project was a success as a large target market for this product was identified that showed great promise. Our team believes that early entrance to the market, as well as the lack of any other competitors would give the team a tremendous advantage in creating an impactful and influential service.
Performance-enhancing drugs (PEDs) have been consumed by athletes in organized sport for as long as the games have been around. Regulation of PEDs began at the turn of this century for many sports, but specific rules vary for each organized body. The inconsistency in regulations has resulted in different length suspensions, even for the same doping offense. What follows is an analysis of the current PED suspensions among the three major sports in the U.S., the MLB, NBA, and NFL, and all other amateur sports that fall under WADA. Various reasons for why the major U.S. sports are not signatories to the World Anti-Doping Code are discussed, along with an in-depth examination of each organization’s banned substances list. A survey collected further data to explain the effect PEDs have on sports fans and non-sports fans alike. A recommendation is made for harmonization of sanctions across global sport. Although it is very unlikely that U.S. sports will ever fall under the jurisdiction of WADA, an independent anti-doping agency for major American sports would be feasible, transparent, and effective at treating athletes more fairly. Furthermore, if this agency focused more on increasing monetary fines for doping violations, rather than increasing suspension lengths, they may be more successful than current policy at lessening PED prevalence.