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- Language: English
- Creators: Arizona Board of Regents
Description
Interictal spikes have been used to diagnose idiopathic seizure disorder and localize the seizure onset zone. Interictal spikes are thought to arise primarily from large excitatory postsynaptic potentials, and the role of interictal spikes in idiopathic seizure disorder and epileptogenesis remains unclear. We evaluated how local voltage changes due to interictal spikes impact action potential generation and firing using intracellular recordings from human tissue and the Hodgkin-Huxley model. During interictal spikes, bursts of action potentials underwent variable degrees of depolarization-induced inactivation in the intracellular data. Intracellular recordings in neocortical slices of human brain tissue confirmed that bursts of inactivated action potentials occurred during spontaneous paroxysmal depolarization shifts. These ex vitro findings were predicted using the Hodgkin-Huxley model and showed inactivated action potentials being generated by large depolarizations. As the amplitude of the interictal spike increased, there was a progression from low firing rate normal action potentials to higher firing rate normal action potentials to inactivated action potentials. The results show that the Hodgkin-Huxley model confirmed the effect of large interictal spike depolarizations on action potential firing and inactivation. This supports a key element in the hypothesis that interictal spikes, and the associated action potential firing, may alter the electrical environment of the brain and contribute to idiopathic seizure disorder.
ContributorsLossner, Lauren Nicole (Author) / Greger, Bradley (Thesis director) / Foldes, Stephen (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
Deep Brain Stimulation (DBS) is a stimulating therapy currently used to treat the motor disabilities that occur as a result of Parkinson’s disease (PD). Previous literature has proven the DBS to be an effective treatment in the effects of PD but the mechanism to validating this phenomenon is poorly understood. In this study, an evaluation of the DBS mechanism was analyzed in patients who received both contralateral and ipsilateral stimulation by the DBS electrode in relation to the recording microelectrode. I hypothesize that the data recorded from the neural tissue of the Parkinson’s patients will exhibit increased electromagnetic field (EMF) fall-off as spatial distance increases among the DBS lead and the microelectrode within the subthalamic nucleus (STN) as a result of the interaction between the EMF exuded by DBS and the neural tissue. Results depicted that EMF fall-off values increased with distance, observable upon comparing ipsilateral and contralateral patient data. The resulting analysis supported this phenomenon evidenced by the production of greater peak voltage amplitudes in ipsilateral patient stimulation with respect to time when compared to contralateral patient stimulation. The understanding of EMF strength and the associated trends among this data are vital to the progression and continued development of the DBS field relative to future research.
ContributorsKiraly, Alexis B (Author) / Greger, Bradley (Thesis director) / Muthuswamy, Jitendran (Committee member) / Harrington Bioengineering Program (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
Functional electrical stimulation (FES) is a technology utilized to attempt to restore motor control in patients affected with paralysis, usually through techniques like intraspinal microstimulation (ISMS). FES uses a surface electrode to delivery extremely small to the target muscles that stimulate their movement and improve signaling within the neighboring nerves. This project sought to measure the impedance of an electrode used for FES in order to characterize other neural structures involved in the electrical impulse transmission process, either through the use of components added to the electrode or through the combination of multiple impedance readings. The electrode used in the present study was composed of 15 microelectrodes, which were fully characterized through electrochemical impedance spectroscopy to analyze the impedance profile with change in frequency. The data points obtained from the microelectrodes were then averaged in order to obtain a larger picture of the impedance of the general electrode. As expected, the impedance of the microelectrodes decreased as frequency increased. The average impedance of a microelectrode at a frequency of 1 kHz was found to be 50 k, although high variance in the data requires further testing to be done to verify the validity of the values that were found.
ContributorsMathew, Ethan (Co-author) / Fonseca, Sebastian (Co-author) / Greger, Bradley (Thesis director) / Mirzadeh, Zaman (Committee member) / W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Epilepsy is a complex neurological disease that affects one in twenty-six people. Despite this prevalence, it is very difficult to diagnose. EpiFinder, Inc. has created an app to better diagnose epilepsy through the use of an epilepsy focused ontology and a heuristic algorithm. Throughout this project, efforts were made to improve the user interface and robustness of the EpiFinder app in order to ease usability and increase diagnostic accuracy. A general workflow of the app was created to aid new users with navigation of the app’s screens. Additionally, numerous diagnostic guidelines provided by the International League Against Epilepsy as well as de-identified case studies were annotated using the Knowtator plug-in in Protégé 3.3.1, where new terms not currently represented in the seizure and epilepsy syndrome ontology (ESSO) were identified for future integration into the ontology. This will help to increase the confidence level of the differential diagnosis reached. A basic evaluation of the user interface was done to provide feedback for the developers for future iterations of the app. Significant efforts were also made for better incorporation of the app into a physician’s typical workflow. For instance, an ontology of a basic review of systems of a medical history was built in Protégé 4.2 for later integration with the ESSO, which will help to increase efficiency and familiarity of the app for physician users. Finally, feedback regarding utility of the app was gathered from an epilepsy support group. These points will be taken into consideration for development of patient-based features in future versions of the EpiFinder app. It is the hope that these various improvements of the app will contribute to a more efficient, more accurate diagnosis of epilepsy patients, resulting in more appropriate treatments and an overall increased quality of life.
ContributorsCsernak, Lidia Maria (Author) / Crook, Sharon (Thesis director) / Greger, Bradley (Committee member) / Yao, Robert (Committee member) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1939
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1944
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1945
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher, Publisher)
Created1948
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1955
Description
Breast cancer affects about 12% of women in the US. Arguably, it is one of the most advertised cancers. Mammography became a popular tool of breast cancer screening in the 1970s, and patient-geared guidelines came from the American Cancer Society (ACS) and the US Preventative Task Force (USPSTF). This research focuses on ACS guidelines, as they were the earliest as well as the most changed guidelines. Mammography guidelines changed over time due to multiple factors. This research has tracked possible causes of those changes. Research began with an extensive literature search of clinical trials, the New York Times and the Washington Post archives, systematic reviews, ACS and USPSTF archives.
ContributorsZiganshina, Dina (Author) / Tuoti, Whitney Alexandra (Editor) / Arizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia. (Publisher) / Arizona Board of Regents (Publisher)
Created2021-02-16